- Two new triterpenoid glycosides from Curculigo orchioides
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Two new cycloartane triterpenoid glycosides, named curculigosaponin N and curculigosaponin O, were isolated from rhizomes of Curculigo orchioides Gaertn. Their structures were elucidated on the basis of comprehensive spectroscopic analysis including IR, M
- Zuo, Ai-Xue,Shen, Yong,Jiang, Zhi-Yong,Zhang, Xue-Mei,Zhou, Jun,Lue, Jun,Chen, Ji-Jun
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- Microbial production of neryl-α-D-glucopyranoside from nerol by Agrobacterium sp. M-12 reflects glucosyl transfer activity
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Terpene alcohol is widely used in perfumes and is known to possess antibacterial activity. Moreover, in its glycosylated form, it can be applied as a nonionic surfactant in food, and in the pharmaceutical, chemical, cosmetic, and detergent industries. Presently, chemical production of terpene glucosides is hampered by high costs and low yields. Here, we investigated the microbial glucosylation of nerol (cis-3,7-dimethylocta-2,6-dien-1-ol), a component of volatile oils, by Agrobacterium sp. M-12 isolated from soil. A microbial reaction using washed cells of Agrobacterium sp. M-12, 1 g/L of nerol, and 100 g/L of maltose under optimal conditions yielded 1.8 g/L of neryl-α-D-glucopyranoside after 72 h. The molar yield of neryl-α-D-glucopyranoside was 87.6%. Additionally, we report the successful transglucosylation of other monoterpene alcohols, such as geraniol, (-)-β-citro-nellol, and (-)-linalool, by Agrobacterium sp. M-12. Thus, microbial glucosylation has potential widespread applicability for efficient, low-cost production of glycosylated terpene alcohols.
- Takahashi, Kazuki,Terauchi, Issei,Ono, Marie,Satoh, Hiroshi,Ueda, Makoto
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- Aryl sulfonic acid catalyzed hydrolysis of cellulose in water
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Catalytic activities of eight alkyl/aryl sulfonic acids in water were compared with sulfuric acid of the same acid strength (0.0321 mol H+ ion/L) for hydrolysis of Sigmacell cellulose (DP ～ 450) in the 140-190 °C temperature range by measuring total reducing sugar (TRS), and glucose produced. Cellulose samples hydrolyzed at 160 °C for 3 h, in aqueous p-toluenesulfonic acid, 2-naphthalenesulfonic acid, and 4-biphenylsulfonic acid mediums produced TRS yields of 28.0, 25.4, and 30.3% respectively, when compared to 21.7% TRS produced in aqueous sulfuric acid medium. The first order rate constants at 160 °C in different acid mediums correlated with octanol/water distribution coefficient log D of these acids, except in the case of highly hydrophobic 4-dodceylbenzenesulfonic acid. In the series of sulfonic acids studied, 4-biphenylsulfonic acid appears to be the best cellulose hydrolysis catalyst.
- Amarasekara, Ananda S.,Wiredu, Bernard
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- Immobilized cellulase on Fe3O4 nanoparticles as a magnetically recoverable biocatalyst for the decomposition of corncob
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A magnetically recoverable biocatalyst was successfully prepared through the immobilization of cellulase onto Fe3O4 nanoparticles. The magnetic nanoparticles were synthesized by a hydrothermal method in an aqueous system. The support (Fe3O4 nanoparticles) was modified with (3-aminopropyl)triethoxysilane, and glutaraldehyde was used as the cross-linker to immobilize the cellulose onto the modified support. Different factors that influence the activity of the immobilized enzyme were investigated. The experimental results indicated that the suitable immobilization temperature and pH are 40 °C and 6.0, respectively. The optimal glutaraldehyde concentration is ～2.0 wt%, and the appropriate immobilization time is 4 h. Under these optimal conditions, the activity of the immobilized enzyme could be maintained at 99.1% of that of the free enzyme. Moreover, after 15 cyclic runs, the activity of the immobilized enzyme was maintained at ～91.1%. The prepared biocatalyst was used to decompose corncobs, and the maximum decomposition rate achieved was 61.94%.
- Zhang, Qikun,Kang, Junqing,Yang, Bing,Zhao, Leizhen,Hou, Zhaosheng,Tang, Bo
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- Flavonoid glucuronides and a chromone from the aquatic macrophyte Stratiotes aloides
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The first phytochemical analysis of the aquatic macrophyte Stratiotes aloides afforded two new flavonoid glucuronides, luteolin 7-O-β-D- glucopyranosiduronic acid-(12)-β-D-glucopyranoside (1) and chrysoeriol 7-O-β-D-glucopyranosiduronic acid-(12)-β-D- glu
- Conrad, Juergen,Foerster-Fromme, Bernhard,Constantin, Mihaela-Anca,Ondrus, Vladimir,Mika, Sabine,Mert-Balci, Fadime,Klaiber, Iris,Pfannstiel, Jens,Moeller, Wolfgang,Roesner, Harald,Foerster-Fromme, Karin,Beifuss, Uwe
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- Hydrolysis of α- and β-D-glucosyl fluoride by individual glucosidases: new evidence for separately controlled "plastic" and "conserved" phases in glycosylase catalysis
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α-Glucosidases from sugar beet seed and ungerminated rice catalyzed the hydrolysis of β-D-glucopyranosyl fluoride to form α-D-glucose.The reactions were slow, with V/K = 11-15 x 10-3 or ca. 1-2percent of that for hydrolysis of p-nitrophenyl α-D-glucopyranoside, but were not due to any impurity in the substrate of to contaminating β-glucosidase or glucomylase.Furthermore, almond β-glucosidase promoted hydrolysis of α-D-glucosyl fluoride to form β-D-glucose at an exceedingly low rate, V/K = 4 x 10-4.This weak reaction did not stem from any impurity in the substrate or to contamination with α-glucosidase or glucomylase, but it was partly (ca. 20percent) attributable to a trace of accompanying trehalase.That all three glucosidases acted upon both α- and β-D-glucosyl fluoride, albeit at low efficiency with the disfavored anomer, reflects the previously demonstrated ability of each enzyme's catalytic groups to respond flexibly to substrates of different types.That the disfavored D-glucosyl fluoride in each case was converted into a product of the same configuration as from enitols or favored D-glucosyl substrates provides additional evidence for the two-step nature of the chemical mechanisms of glucosidases, in which the stereochemistry of water attack on the enzyme-stabilized oxocarbonium ion is strictly maintained, regardless of the initial anomeric configuration of the substrate.
- Matsui, Hirokazu,Tanaka, Yoshimasa,Brewer, Curtis F.,Blanchard, John S.,Hehre, Edward J.
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- Structural elements responsible for the glucosidic linkage-selectivity of a glycoside hydrolase family 13 exo-glucosidase
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Abstract Glycoside hydrolase family 13 contains exo-glucosidases specific for α-(1 → 4)- and α-(1 → 6)-linkages including α-glucosidase, oligo-1,6-glucosidase, and dextran glucosidase. The α-(1 → 6)-linkage selectivity of Streptococcus mutans dextran glucosidase was altered to α-(1 → 4)-linkage selectivity through site-directed mutations at Val195, Lys275, and Glu371. V195A showed 1300-fold higher kcat/Km for maltose than wild-type, but its kcat/Km for isomaltose remained 2-fold higher than for maltose. K275A and E371A combined with V195A mutation only decreased isomaltase activity. V195A/K275A, V195A/E371A, and V195A/K275A/E371A showed 27-, 26-, and 73-fold higher kcat/Km for maltose than for isomaltose, respectively. Consequently, the three residues are structural elements for recognition of the α-(1 → 6)-glucosidic linkage.
- Saburi, Wataru,Rachi-Otsuka, Hiroaki,Hondoh, Hironori,Okuyama, Masayuki,Mori, Haruhide,Kimura, Atsuo
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- Gluconic acid from biomass fast pyrolysis oils: Specialty chemicals from the thermochemical conversion of biomass
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Fast pyrolysis of biomass to produce a bio-oil followed by catalytic upgrading is a widely studied approach for the potential production of fuels from biomass. Because of the complexity of the bio-oil, most upgrading strategies focus on removing oxygen from the entire mixture to produce fuels. Here we report a novel method for the production of the specialty chemical, gluconic acid, from the pyrolysis of biomass. Through a combination of sequential condensation of pyrolysis vapors and water extraction, a solution rich in levoglucosan is obtained that accounts for over 30% of the carbon in the biooil produced from red oak. A simple filtration step yields a stream of high-purity levoglucosan. This stream of levoglucosan is then hydrolyzed and partially oxidized to yield gluconic acid with high purity and selectivity. This combination of costeffective pyrolysis coupled with simple separation and upgrading could enable a variety of new product markets for chemicals from biomass.
- Santhanaraj, Daniel,Rover, Marjorie R.,Resasco, Daniel E.,Brown, Robert C.,Crossley, Steven
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- Acremonoside, a phenolic glucoside from the sea fan-derived fungus Acremonium polychromum PSU-F125
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A new phenolic glucoside, acremonoside (1), along with two known compounds, F-11334 A2and 2,2-dimethyl-2H-chromen-6-ol, were isolated from the sea fan-derived fungus Acremonium polychromum PSU-F125. The structure of 1 was elucidated by spectroscopic techniques, acid hydrolysis and X-ray crystallographic analysis. The isolated compounds were tested for antibacterial, antimalarial, antimycobacterial and cytotoxic activities.
- Khamthong, Nanthaphong,Rukachaisirikul, Vatcharin,Pakawatchai, Chaveng,Saithong, Saowanit,Phongpaichit, Souwalak,Preedanon, Sita,Sakayaroj, Jariya
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- Catalytic properties and amino acid sequence of endo-1→3-β-D- glucanase from the marine mollusk Tapes literata
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A specific 1→3-β-D-glucanase with molecular mass 37 kDa was isolated in homogeneous state from crystalline style of the commercial marine mollusk Tapes literata. It exhibits maximal activity within the pH range from 4.5 to 7.5 at 45°C. The 1→3-β-D-glucanase catalyzes hydrolysis of β-1?3 bonds in glucans as an endoenzyme with retention of bond configuration, and it has transglycosylating activity. The Km for hydrolysis of laminaran is 0.25 mg/ml. The enzyme is clas- sified as a glucan endo-(1→3)-β-D-glucosidase (EC 3.2.1.39). The cDNA encoding this 1→3-β-D-glucanase from T. lit- erata was sequenced, and the amino acid sequence of the enzyme was determined. The endo-1→3-β-D-glucanase from T. literata was assigned to the 16th structural family (GHF 16) of O-glycoside hydrolases.
- Zakharenko, A. M.,Kusaykin, M. I.,Kovalchuk, S. N.,Sova, V. V.,Silchenko, A. S.,Anastyuk, S. D.,Rasskazov, V. A.,Zvyagintseva, T. N.,Belik, A. A.,Ly, Bui Minh
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- Two new secondary metabolites from xylaria sp. cfcc 87468
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A new isocoumarin glycoside, 3R-(+)-5-O-[6'-O-Acetyl]-A-D-glucopyranosyl-5- hydroxymellein (1), and a new phenylethanol glycoside, (-)-phenylethyl-8-O-A-L- rhamnopyranoside (2), were isolated from the ethyl acetate extract of the fungus Xylaria sp. cfcc 87468, together with five known steroids, ss-sitosterol (3), stigmast-4-en-3- one (4), ergosterol (5), (22E)-cholesta-4,6,8(14),22- tetraen-3-one (6), and 4a-methylergosta- 8(14),24(28)-dien-3ss-ol (7). The structures of compounds 1 and 2 were elucidated by MS, extensive 1D and 2D NMR spectroscopy, and the circular dichroism (CD) spectroscopy.
- Wang, Fuqian,Han, Shishi,Hu, Song,Xue, Yongbo,Wang, Jianping,Xu, Hongfeng,Chen, Lu,Zhang, Geng,Zhang, Yonghui
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- Yihx-encoded haloacid dehalogenase-like phosphatase HAD4 from Escherichia coli is a specific α-d-glucose 1-phosphate hydrolase useful for substrate-selective sugar phosphate transformations
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Phosphomonoester hydrolases (phosphatases; EC 3.1.3.) often exhibit extremely relaxed substratespecificity which limits their application to substrate-selective biotransformations. In search of a phos-phatase catalyst specific for hydrolyzing α-d-glucose 1-phosphate (αGlc 1-P), we selected haloaciddehalogenase-like phosphatase 4 (HAD4) from Escherichia coli and obtained highly active recombinantenzyme through a fusion protein (Zbasic2HAD4) that contained Zbasic2, a strongly positively chargedthree α-helical bundle module, at its N-terminus. Highly pure Zbasic2HAD4 was prepared directly fromE. coli cell extract using capture and polishing combined in a single step of cation exchange chro-matography. Kinetic studies showed Zbasic2HAD4 to exhibit 565-fold preference for hydrolyzing αGlc 1-P (kcat/KM= 1.87 ± 0.03 mM?1s?1; 37°C, pH 7.0) as compared to d-glucose 6-phosphate (Glc 6-P). Alsoamong other sugar phosphates, αGlc 1-P was clearly preferred. Using different mixtures of αGlc 1-P and Glc 6-P (e.g. 180 mM each) as the substrate, Zbasic2HAD4 could be used to selectively convert the αGlc1-P present, leaving back all of the Glc 6-P for recovery. Zbasic2HAD4 was immobilized conveniently usingdirect loading of E. coli cell extract on sulfonic acid group-containing porous carriers, yielding a recyclableheterogeneous biocatalyst that was nearly as effective as the soluble enzyme, probably because proteinattachment to the anionic surface occurred in a preferred orientation via the cationic Zbasic2module.Selective removal of αGlc 1-P from sugar phosphate preparations could be an interesting application ofZbasic2HAD4 for which readily available broad-spectrum phosphatases are unsuitable.
- Pfeiffer, Martin,Wildberger, Patricia,Nidetzky, Bernd
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- Aglycon specificity profiling of α-glucosidases using synthetic probes
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We designed and synthesized hydrogen bond based probes 1-8 with the exception of known glycosidase inhibition mechanisms, and aglycon specificity of 11 different sources of α-glucosidases were investigated using their probes. Probe 4 (2,6-anhydro-1-deoxy-1-[(1-oxopentyl-5-hydroxy)amino]-d-glycero- d-ido-heptitol) showed a potent inhibition of S. cerevisiae α-glucosidase among all α-glucosidases. Probe 4 was found to be a competitive inhibitor for S. cerevisiae α-glucosidase with Ki 0.13 mM.
- Hakamata, Wataru,Muroi, Makoto,Kadokura, Kazunari,Nishio, Toshiyuki,Oku, Tadatake,Kimura, Atsuo,Chiba, Seiya,Takatsuki, Akira
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- Protein nanotubes with an enzyme interior surface
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This report describes the synthesis and enzyme activities of multilayered protein nanotubes with an α-glucosidase (αGluD) interior surface. The nanotubes were prepared by using an alternating layer-by-layer (LbL) assembly of human serum albumin (HSA) and oppositely charged poly-L-arginine (PLA) into a track-etched polycarbonate (PC) membrane (pore size=400a nm) followed by addition of αGluD as the last layer of the wall. Subsequent dissolution of the PC template yielded (PLA/HSA)2PLA/αGluD nanotubes. SEM measurements revealed the formation of uniform hollow cylinders with (413A±17)a nm outer diameter and (52A±3)a nm wall thickness. In aqueous media, the nanotubes captured a fluorogenic glucopyranoside, 4-methyl-umbelliferyl-α-D-glucopyranoside (MUGlc), into their one-dimensional pore space and hydrolyzed the substrate efficiently to form α-D-glucose. We determined the enzyme parameters (Michaelis constant, KM, and catalytic constant, kcat, values) of the protein nanotubes. The several-micrometers-long cylinders were of sufficient length to be spun down by centrifugation at 4000a g, so the product could therefore be easily separated. Similar biocatalysts were prepared by complexation of biotinylated-αGluD into HSA-based nanotubes bearing a single avidin layer as an internal surface. The obtained hybrid nanotubes also exhibited the same enzyme activity for the MUGlc hydrolysis.
- Komatsu, Teruyuki,Terada, Hiromi,Kobayashi, Nao
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- Antibacterial activity of glucomoringin bioactivated with myrosinase against two important pathogens affecting the health of long-term patients in hospitals
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Glucosinolates (GLs) are natural compounds present in species of the order Brassicales and precursors of bioactive isothiocyanates (ITCs). In the recent years, they have been studied mainly for their chemopreventive as well as novel chemotherapeutics properties. Among them 4-(α-L-rhamnosyloxy)benzyl glucosinolate (glucomoringin; GMG), purified from seeds of Moringa oleifera Lam., a plant belonging to the Moringaceae family, represents an uncommon member of the GL family with peculiar characteristics. This short communication reports new evidences about the properties of GMG and presents a new innovative utilization of the molecule. The bioactivation of GMG by myrosinase enzyme just before treatment, permits to maximize the power of the final product of the reaction, which is the 4-(α-L-rhamnosyloxy)benzyl isothiocyanate (GMG-ITC). We tested the antibiotic activity of this latter compound on two strains of pathogens affecting the health of patients in hospital, namely Staphylococcus aureus and Enterococcus casseliflavus, and on the yeast Candida albicans. Results show that the sensibility of S. aureus BAA-977 strain and E. casseliflavus to GMG-ITC treatment reveals an important possible application of this molecule in the clinical care of patients, more and more often resistant to traditional therapies.
- Galuppo, Maria,De Nicola, Gina Rosalinda,Iori, Renato,Dell'Utri, Pia,Bramanti, Placido,Mazzon, Emanuela
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- Cellodextrin phosphorylase from Ruminiclostridium thermocellum: X-ray crystal structure and substrate specificity analysis
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The GH94 glycoside hydrolase cellodextrin phosphorylase (CDP, EC 2.4.1.49) produces cellodextrin oligomers from short β-1→4-glucans and α-D-glucose 1-phosphate. Compared to cellobiose phosphorylase (CBP), which produces cellobiose from glucose and α-D-glucose 1-phosphate, CDP is biochemically less well characterised. Herein, we investigate the donor and acceptor substrate specificity of recombinant CDP from Ruminiclostridium thermocellum and we isolate and characterise a glucosamine addition product to the cellobiose acceptor with the non-natural donor α-D-glucosamine 1-phosphate. In addition, we report the first X-ray crystal structure of CDP, along with comparison to the available structures from CBPs and other closely related enzymes, which contributes to understanding of the key structural features necessary to discriminate between monosaccharide (CBP) and oligosaccharide (CDP) acceptor substrates.
- O'Neill, Ellis C.,Pergolizzi, Giulia,Stevenson, Clare E.M.,Lawson, David M.,Nepogodiev, Sergey A.,Field, Robert A.
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- Purification, antioxidant activity and antiglycation of polysaccharides from Polygonum multiflorum Thunb
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Polysaccharides, one of the most important constituents in Polygonum multiflorum Thunb, a famous Chinese medicinal herb, were isolated by DEAE-52, Sepharose 4B and Sephacryl S-300 column chromatography. Two polysaccharides (PMP-1 and PMP-2) were identified as homogeneous in molecular weight with HPLC. The molecular weights were 4.8 × 102 and 6.1 × 10 2 kDa, respectively. Antioxidant activity tests were performed with two polysaccharides at concentrations of 0.1-1.5 mg/mL. The results indicated that the inhibitory activity on oxidation and glycation exhibited a dose-dependent response. PMP-2 exhibited a much stronger antioxidant capacity against free radical, lipid oxidation and protein glycation. The IC50 values of PMP-2 were 0.47, 0.6 and 0.93 mg/mL for superoxide anion scavenging, hydroxyl radical scavenging, and hydroxyl peroxide scavenging, respectively. The inhibitory ability of PMP-2 on lipid oxidation was most markedly in rat liver, followed by heart and kidney. Meanwhile, PMP-2 also showed satisfactory suppression of AGEs formation. This suggested that the polysaccharides present in PM can contribute to the biological effects.
- Lv, Lishuang,Cheng, Yunhui,Zheng, Tiesong,Li, Xiaoming,Zhai, Rong
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- A novel macrolactam-disaccharide antifungal antibiotic taxonomy, fermentation, isolation, physico-chemical properties, structure elucidation and biological activity
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A novel natural product (1), with antifungal activity was isolated from the culture broth of an actinomadurae. The active compound was separated from broth by n-butanol extraction and purified by silica gel and multicoil counter current chromatography. Physico-chemical data suggested the structure of this compound to be a novel macrolactam disaccharide related to Sch 38518 (3). The structure was determined by spectroscopic studies on the acetate derivative. It was active against Candida spp. (MIC's, 4~64 μg/ml) but less active than the monosaccharide, Sch 38518 (MIC's, 1~ 16μg/ml).
- Hegde,Patel,Gullo,Horan,King,Gentile,Wagman,Puar,Loebenberg
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- Asplenetin, a flavone and its glycoside from Launaea asplenifolia
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A new flavone, asplenetin, has been isolated from Launea asplenifolia and characterized as 5,7,3′,4′,5′-pentahydroxy-3-(3-methylbutyl)flavone. Its glycoside, asplenetin 5-O-neohesperidoside, is also reported.
- Gupta,Ahmed, Bahar
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- Hepatoprotective triterpenoid saponins from Callicarpa nudiflora
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Four new triterpenoid saponins, 2α,3α,19α,24- tetrahydroxyolean-12-en-28-oic-acid 28-O-β-D-glucopyranosyl ester (1), 2α,3α,19α, 23-tetrahydroxyolean-12-en-28-oic-acid 28-O-β-D-xylopyranosyl-(1→2)-β-D-glucopyranosyl ester (2), 2α,3α,19α-trihydroxyolean-12-
- Huang, Bo,Fu, Hui-Zheng,Chen, Wei-Kang,Luo, Yue-Hua,Ma, Shuang-Cheng
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- Sonochemical synthesis of HSiW/graphene catalysts for enhanced biomass hydrolysis
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Hydrolysis of biomass for the production of glucose was studied. Silicotungstic acid (HSiW) was deposited on graphene by an ultrasound-assisted procedure. The catalyst (HSiW/G) was characterized using a variety of physico-chemical methods. Homogeneous distribution of HSiW on the surface of graphene was demonstrated. The hydrolysis of glycogen was performed with a HSiW/G catalyst by hydrothermal treatment. The yield of glucose (66 wt%) obtained was about 8 times higher than that obtained with the same amount of bare HSiW. Stability of the HSiW/graphene even after 3 repeated uses was confirmed. The mechanism of the enhancement of catalytic activity was discussed in terms of a special interaction between the graphene support and HSiW and also the appearance of hydrophobic cavities on the surface of graphene. The formation of these cavities facilitates the anchoring of glycogen to the catalyst surface and promotes the attack of protons that leads to selective, rapid, and efficient hydrolysis.
- Klein, Miri,Varvak, Alexander,Segal, Elad,Markovsky, Boris,Pulidindi, Indra Neel,Perkas, Nina,Gedanken, Aharon
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- Exopolysaccharide Produced by Probiotic Bacillus albus DM-15 Isolated From Ayurvedic Fermented Dasamoolarishta: Characterization, Antioxidant, and Anticancer Activities
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An exopolysaccharide (EPS) was purified from the probiotic bacterium Bacillus albus DM-15, isolated from the Indian Ayurvedic traditional medicine Dasamoolarishta. Gas chromatography-mass spectrophotometry and nuclear magnetic resonance (NMR) analyses revealed the heteropolymeric nature of the purified EPS with monosaccharide units of glucose, galactose, xylose, and rhamnose. Size-exclusion chromatography had shown the molecular weight of the purified EPS as around 240 kDa. X-ray powder diffraction analysis confirmed the non-crystalline amorphous nature of the EPS. Furthermore, the purified EPS showed the maximum flocculation activity (72.80%) with kaolin clay and emulsification activity (67.04%) with xylene. In addition, the EPS exhibits significant antioxidant activities on DPPH (58.17 ± 0.054%), ABTS (70.47 ± 0.854%) and nitric oxide (58.92 ± 0.744%) radicals in a concentration-dependent way. Moreover, the EPS showed promising cytotoxic activity (20 ± 0.97 μg mL–1) against the lung carcinoma cells (A549), and subsequent cellular staining revealed apoptotic necrotic characters in damaged A549 cells. The EPS purified from the probiotic strain B. albus DM-15 can be further studied and exploited as a potential carbohydrate polymer in food, cosmetic, pharmaceutical, and biomedical applications.
- Kalimuthu, Palanisamy,Ma, Yongkun,Mathivanan, Krishnamurthy,Rai, Amit Kumar,Saravanan, Kandasamy,Sathiyanarayanan, Ganesan,Sekar, Soundarapandian,Sudharsan, Kumaresan,Vinothkanna, Annadurai
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- Bifunctional heterogeneous catalysts derived from the coordination of adenosine monophosphate to Sn(iv) for effective conversion of sucrose to 5-hydroxymethylfurfural
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Adenosine 5′-monophosphate (AMP) with multiple functional groups can bind to various metal ions. In this work, AMP has been used as a ligand to coordinate Sn(iv) for the synthesis of porous coordination polymers (Sn-AMPs). The Sn-AMPs have both Br?nsted acid (BA) and Lewis acid (LA) sites and have been used as bifunctional heterogeneous catalysts for catalyzing the conversion of sucrose to 5-hydroxymethylfurfural (HMF), involving hydrolysis of sucrose to glucose and fructose, isomerization of glucose to fructose, and dehydration of fructose to HMF. The protonated N1 and OH–P of the coordinated AMP can form hydrogen bonds with glucose and fructose. This can promote the conversion of the sugars. Sn-AMP has exhibited a superior capability for the conversion of biomass-derived sugars into HMF. The HMF yields of 76.1%, 67.5% and 62.9% were achieved from fructose, glucose, and sucrose, respectively.
- Ji, Peijun,Jiao, Lutong,Meng, Han,Wang, Chenyu
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p. 630 - 640
(2022/02/09)
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- Enzyme aggregation and fragmentation induced by catalysis relevant species
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It is usually assumed that enzymes retain their native structure during catalysis. However, the aggregation and fragmentation of proteins can be difficult to detect and sometimes conclusions are drawn based on the assumption that the protein is in its native form. We have examined three model enzymes, alkaline phosphatase (AkP), hexokinase (HK) and glucose oxidase (GOx). We find that these enzymes aggregate or fragment after addition of chemical species directly related to their catalysis. We used several independent techniques to study this behavior. Specifically, we found that glucose oxidase and hexokinase fragment in the presence ofd-glucose but notl-glucose, while hexokinase aggregates in the presence of Mg2+ion and either ATP or ADP at low pH. Alkaline phosphatase aggregates in the presence of Zn2+ion and inorganic phosphate. The aggregation of hexokinase and alkaline phosphatase does not appear to attenuate their catalytic activity. Our study indicates that specific multimeric structures of native enzymes may not be retained during catalysis and suggests pathways for different enzymes to associate or separate over the course of substrate turnover.
- Adair, James,Bhide, Ashlesha,Gentile, Kayla,Ghosh, Subhadip,Kauffman, Joshua,Lee, Tae-Hee,Maiti, Subhabrata,Sen, Ayusman
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p. 20709 - 20717
(2021/10/02)
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- New benzoic acid and caffeoyl derivatives with anti-inflammatory activities isolated from leaves of Ilex kaushue
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A new benzoic acid, 3-[2-(2-hydroxyphenyl)acetoxy]benzoic acid (1), and two new caffeoyl derivatives, methyl (3E,5Z)-di-O-caffeoylquinate (2) and dhurrin 6′-O-caffeate (3), along with 20 known compounds were isolated from the leaves of Ilex kaushue collected in Vietnam. Their structures were elucidated on the basis of 1 D and 2 D NMR spectroscopy, and high-resolution MS spectrometry. The absolute configuration of 2 and 3 was unambiguously established by comparison of experimental and calculated ECD spectra and/or chemical reactivity. In addition, new compounds were evaluated for inhibitory effects of their tumor necrosis factor-α (TNF-α) production and cell cytotoxicity on lipopolysaccharide-induced RAW264 macrophage cells. All of those moderately suppressed TNF-α production in ratios of approximately 50% or higher at 25–100 μM, without cell cytotoxicity.
- Kakumu, Yuya,Mitsunaga, Tohru,Nguyen, Thi Minh Tu,Yamauchi, Kosei
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- Acylated iridoid glycosides with hyaluronidase inhibitory activity from the rhizomes of Picrorhiza kurroa Royle ex Benth
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Seven new acylated iridoid glycosides, picrorhizaosides A–G (1–7), were isolated from the methanol extract of the rhizomes of Picrorhiza kurroa Royle ex Benth. (Plantaginaceae), in addition to six known iridoid glycosides (8–13). The structures of these new iridoids, including their stereochemistry, were determined based on chemical and physicochemical evidence derived from NMR and MS analysis. Of the isolates, picrorhizaosides D (4, IC50 = 43.4 μM) and E (5, 35.8 μM); picrosides I (8, 60.7 μM), II (9, 22.3 μM), and IV (11, 59.2 μM); and minecoside (13, 57.2 μM), exhibited a similar or stronger hyaluronidase inhibitory activity than those of the antiallergic medicines disodium cromoglycate (64.8 μM), ketotifen fumarate (76.5 μM), and tranilast (227 μM).
- Morikawa, Toshio,Nakanishi, Yusuke,Inoue, Naoki,Manse, Yoshiaki,Matsuura, Hideyuki,Hamasaki, Shinya,Yoshikawa, Masayuki,Muraoka, Osamu,Ninomiya, Kiyofumi
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- FeVO4 decorated –SO3H functionalized polyaniline for direct conversion of sucrose to 2,5-diformylfuran & 5-ethoxymethylfurfural and selective oxidation reaction
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In this study, a multi-functional catalyst, FeVO4 supported –SO3H functionalized polyaniline is prepared. First FeVO4 supported polyaniline is prepared. Then the resultant material is sulfonated using chlorosulphonic acid to obtain FeVO4 supported –SO3H functionalized polyaniline. This multi-functional catalyst exhibits excellent activity in the synthesis of 5-hydroxymethylfurfural from sucrose and oxidation of a wide range of aromatic and aliphatic alcohols. Further, the catalyst exhibits very good activity in the one-pot direct conversion of sucrose/fructose to 2,5-diformylfuran (DFF) and 5-ethoxymethylfurfural (EMF). This catalytic process involves the economical sucrose as a reactant and economical multi-functional catalyst based on polyaniline. In this one-pot, two-step process, -SO3H functionalized polyaniline is used in the first step for the conversion of sucrose to 5-hydroxymethylfurfural (HMF) followed by selective oxidation of HMF to DFF using FeVO4 sites present in the multi-functional catalyst. Moreover, acidic sites present in the multi-functional catalyst are suitable for the conversion of sucrose/fructose/HMF to EMF. Furthermore, molecular oxygen (1 atmosphere, 10 ml/min) is used as an eco-friendly and economical oxidant for the selective oxidation of a wide range of aromatic and aliphatic alcohols to aldehydes. The multi-functional catalyst presented here has been easily separated and recycled that make the process sustainable and economical for commercial perspectives.
- Kumar, Abhinav,Srivastava, Rajendra
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- A Systematic Study of Metal Triflates in Catalytic Transformations of Glucose in Water and Methanol: Identifying the Interplay of Br?nsted and Lewis Acidity
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The specific type of acidity associated with the given metal trifloromethanesulfonates (Br?nsted or Lewis acidity) dramatically influences the course of reactions, and it is possible to select for disaccharides, fructose, methyl glucosides, or methyl levulinate. Glucose is transformed into a range of value-added molecules in water and methanol under the action of acidic metal triflates as catalysts, including their analogous Br?nsted acid-assisted or Br?nsted base-modified systems. A systematic study is presented of a range of metal triflates in methanol and water, pinning down the preferred conditions to select for each product.
- Bodachivskyi, Iurii,Kuzhiumparambil, Unnikrishnan,Williams, D. Bradley G.
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- Use of a deoxynojirimycin–fluorophore conjugate as a cell-specific imaging probe targeting α-glucosidase on cell membranes
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Molecules designed for cell-specific imaging were studied, taking advantage of an enzyme–inhibitor interaction. 1-Deoxynojirimycin (DNJ) can be actively captured by cells which express the surface membrane protein α-glucosidase. New probes composed of DNJ for recognition linked to a fluorophore signal portion were prepared (DNJ-CF3 1, DNJ-Dans 2 and DNJ-DEAC 3). Docking simulations revealed that the inhibitors acarbose and miglitol and the inhibitor portion of the probes bind at the same position in the pocket of α-glucosidase (human-derived PDB: 3TON). The ability of probes 1–3 to detect the difference between HeLa cells (from human cervical cancer tissue), Neuro-2a cells (from a mouse neuroblastoma C1300 tumor), N1E-115 cells (from a mouse brain neuroblastoma C1300 tumor), A1 cells (from the astrocyte of a newborn mouse brain), and Caco-2 cells (from a human colon carcinoma) was evaluated, and cell-specific fluorescence imaging was possible for conjugate probes 1 and 2. Caco-2 cells treated with probes 1 and 2 showed blue and green fluorescence, respectively, from the cell membrane, and did not stain the Caco-2 cells inside. These results show that DNJ-CF3 1 and DNJ-Dans 2 recognize an α-glucosidase protein on the surface of Caco-2 cells. Probes 1 and 2 did not stain any part of the other cells. This cell-specific imaging strategy is applicable for a variety of therapeutic agents for many diseases.
- Hatano, Akihiko,Kanno, Yuichi,Kondo, Yuya,Sunaga, Yuta,Umezawa, Hatsumi,Fukui, Koji
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supporting information
p. 859 - 864
(2019/02/06)
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- Investigation of inhibition effects of some natural phenolic compounds on Glutathione S-transferase (GST), Acetylcholinesterase (AChE), Butyrylcholinesterase (BChE), α-amylase, and α-glycosidase: Antidiabetic, anticholinergics, antiparasitic study
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Summary: Herein, we report the experimental results of the inhibition effects of some phenolic compounds such as 2,4,6-Trihydroxybenzaldehyde, 3,4-Dihydroxy-5-methoxybenzoic acid, Serotonin hydrochloride on α-amylase, α-glycosidase, acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and glutathione S-transferase (GST) enzymes. α-Amylase from porcine pancreas, α-glycosidase from Saccharomyces cerevisiae, glutathione s-transferase from human placenta, acetylcholinesterase from human erythrocytes and Butyrylcholinesterase from equine serum were used as enzymes. These enzymes play a very important role in metabolism. In this study the Ki values obtained by the experiments done for the compounds on some enzymes such as GST, AChE, BChE, α-amylase and α-glycosidase were found in the range of 0.31±0.5-1.02±0.3 μM, 484.03±45.45-802.83±104.3 μM, 238.22±67.31-482.73±125.6 μM and 9.28±0.56-11.23±3.43 μM, respectively. The experiment results showed that the α-amylase enzyme has a selective inhibitory effect and its IC50 values were found to be in the range of 0.92-9.63 μM. As a result, it was found that these phenolic compounds have a selective effect on α-amylase, α-glycosidase, AChE, BChE and GST enzymes, and they can be used as antiparasitic, antidiabetic and anticholinergic.
- Turkan, Fikret
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p. 714 - 721
(2019/09/18)
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- Mechanistic insights into enzymatic catalysis by trehalase from the insect gut endosymbiont Enterobacter cloacae
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Energy metabolism in the diamondback moth Plutella xylostella is facilitated by trehalase, an enzyme which assists in trehalose hydrolysis, from the predominant gut bacterium Enterobacter cloacae. We report the biochemical and structural characterization of recombinant trehalase from E. cloacae (Px_EclTre). Px_EclTre showed KM of 1.47 (±0.05) mm, kcat of 6254.72 min?1 and Vmax 0.2 (±0.002) mm·min?1 at 55 °C and acidic pH. Crystal structures of Px_EclTre were determined in the ligand-free form and bound to the inhibitor Validoxylamine A. The crystal structure of the ligand-free form, unavailable until now for any other bacterial trehalases, enabled us to delineate the conformational changes accompanying ligand binding in trehalases. Multiple salt bridges were identified that potentially facilitated closure of a hood over the substrate-binding site. A cluster of five tryptophans lined the ?1 substrate-binding subsite, interacted with crucial active site residues and contributed to both trehalase activity and stability. The importance of these residues in enzyme activity was further validated by mutagenesis studies. Many of these identified residues form part of signature motifs and other conserved sequences in trehalases. The structure analysis thus led to the assignment of the functional role to these conserved residues. This information can be further explored for the design of effective inhibitors against trehalases.
- Adhav, Anmol,Harne, Shrikant,Bhide, Amey,Giri, Ashok,Gayathri, Pananghat,Joshi, Rakesh
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p. 1700 - 1716
(2019/02/20)
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- Leather-Promoted Transformation of Glucose into 5-Hydroxymethylfurfural and Levoglucosenone
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The search for efficient catalysts frequently leads to new homogeneous and heterogeneous catalysts of increasing complexity, and sometimes common, natural, or hybrid natural/synthetic materials that could be used in catalysis are overlooked. For example, the leather industry has produced robust Cr-containing materials for centuries by chemical treatment of animal hides with chromium salts. Herein, the use of chromium-tanned leather as a heterogeneous catalyst for glucose dehydration to 5-hydroxymethylfurfural (5-HMF) and levoglucosenone (LGO) is reported. Four pieces of waste leather were obtained from shoe soles and a belt, characterized by a range of techniques including FTIR spectroscopy, SEM, BET surface area measurements, XRD, and X-ray photoelectron spectroscopy, and their catalytic activity was evaluated. The activity of the scrap leather pieces compares favorably to those of many recently reported catalysts for the preparation of 5-HMF, but additionally results in significant quantities of LGO. Overall, the results demonstrate that waste leather is an outstanding material for use in catalysis.
- Bobbink, Felix D.,Huang, Zhangjun,Menoud, Florent,Dyson, Paul J.
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p. 1437 - 1442
(2019/04/14)
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- Structure elucidation of a novel oligosaccharide (Medalose) from camel milk
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Free oligosaccharides are the third most abundant solid component in milk after lactose and lipids. The study of milk oligosaccharides indicate that nutrients are not only benefits the infant's gut but also perform a number of other functions which include stimulation of growth, receptor analogues to inhibit binding of pathogens and substances that promote postnatal brain development. Surveys reveal that camel milk oligosaccharides possess varied biological activities that help in the treatment of diabetes, asthma, anaemia, piles and also a food supplement to milking mothers. In this research, camel milk was selected for its oligosaccharide contents, which was then processed by Kobata and Ginsburg method followed by the HPLC and CC techniques. Structure elucidation of isolated compound was done by the chemical degradation, chemical transformation and comparison of chemical shift of NMR data of natural and acetylated oligosaccharide structure reporter group theory, the 1H, 13C NMR, 2D-NMR (COSY, TOCSY and HSQC) techniques, and mass spectrometry. The structure was elucidated as under: MEDALOSE[Figure presented]
- Gangwar, Lata,Singh, Rinku,Deepak, Desh
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p. 157 - 161
(2017/10/13)
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- Using the 3-Diethylaminobenzyl Group as a Photocage in Aqueous Solution
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We have demonstrated that the 3-diethylaminobenzyl (DEABn) photolabile protecting group (PPG) is an effective and structurally simple PPG for releasing molecules in aqueous environment. In general, the photoreaction is clean, and the released substrate and the PPG product, i.e., 3-diethylaminobenzyl alcohol, are obtained in high yield. The clean photoreaction can also be achieved under mild ambient conditions with sunlight, while the reactant is stable under indoor lighting. Release of two substrates from one PPG chromophore in aqueous solution has been demonstrated to be feasible. We have also compared the uncaging properties of the DEABn and the widely used o-nitrobenzyl (o-NB) group, given their comparable structural simplicity. With its clean and efficient photochemical reaction, DEABn should find wide applications, including in the basic and applied research areas where o-NB and its various derivatives are widely used.
- Ding, Xiong,Wang, Pengfei
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p. 7459 - 7466
(2018/05/29)
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- Phenolic Constituents from Fallopia multiflora (Thunberg) Haraldson
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Four naphtolic glycosides (1-4), three anthraquinones (5-7), two stilbenes (8-9), one benzyl glycoside (10), and one flavonoid (11) were isolated from the roots of Fallopia multiflora. The new compounds were elucidated to be 6-hydroxymusizin 8-O-α-D-apiof
- Nguyen, Thi Thoa,Pham, Thanh Binh,Thao, Nguyen Phuong,Dang, Nguyen Hai,Nguyen, Van Hung,Pham, Van Cuong,Minh, Chau Van,Tran, Quang Hai,Dat, Nguyen Tien
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- Dynamic formation of nanostructured particles from vesicles via invertase hydrolysis for on-demand delivery
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The unique multicompartmental nanostructure of lipid-based mesophases can be triggered, on-demand, in order to control the release of encapsulated drugs. In this study, these nanostructured matrices have been designed to respond to a specific enzyme, invertase, an enzyme which catalyses the hydrolysis of sucrose. The effect of two sugar esters upon the phase behaviour of two different lipids which form cubic phases, phytantriol and monolinolein, was investigated. Factors affecting the hydrolysis of the sucrose headgroup are discussed in terms of the molecular structure of the sugar surfactant and also its ability to incorporate into the lipid bilayer. By hydrolysing the incorporated sugar esters, a dynamic change in mesophase nanostructure from vesicles to a cubic phase was observed. This phase change resulted in the triggered release of an encapsulated model drug, fluorescein. This investigation demonstrates, for the first time, that changes on a molecular level by subtly controlling the hydrophilic and hydrophobic features of an amphiphilic additive at the interface by enzymatic hydrolysis can result in a global change in the system and so paves the way towards the design and development of lipid-based matrices which are responsive to specific enzymes for the controlled delivery of pharmaceutically active molecules or functional foods.
- Fong, Wye-Khay,Sánchez-Ferrer, Antoni,Ortelli, Francesco Giovanni,Sun, Wenjie,Boyd, Ben J.,Mezzenga, Raffaele
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p. 4368 - 4377
(2017/01/29)
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- A new phenolic glycoside from the stem of Dendrobium nobile
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A new phenolic glycoside dendroside (1), together with seven known compounds (2–8) were isolated from the stems of Dendrobium nobile. The structures of these compounds were elucidated using comprehensive spectroscopic methods. The inhibitory activities of all compounds against three cancer cell lines HeLa, MCF-7 and A549 were evaluated.
- Zhou, Xue-Ming,Zheng, Cai-Juan,Wu, Jia-Ting,Chen, Guang-Ying,Zhang, Bin,Sun, Chong-Ge
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p. 1042 - 1046
(2017/01/28)
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- Bioactive constituents from the whole plants of gentianella acuta (Michx.) Hulten
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As a Mongolian native medicine and Ewenki folk medicinal plant, Gentianella acuta has been widely used for the treatment of diarrhea, hepatitis, arrhythmia, and coronary heart disease. In the course of investigating efficacy compounds to treat diarrhea using a mouse isolated intestine tissue model, we found 70% EtOH extract of G. acuta whole plants had an inhibitory effect on intestine contraction tension. Here, nineteen constituents, including five new compounds, named as gentiiridosides A (1), B (2), gentilignanoside A (3), (1R)-2,2,3-trimethyl-4-hydroxymethylcyclopent-3-ene-1-methyl-O-β-D-glucopyranoside (4), and (3Z)-3-hexene-1,5-diol 1-O-α-L-arabinopyranosyl(1→6)-β-D-glucopyranoside (5) were obtained from it. The structures of them were elucidated by chemical and spectroscopic methods. Furthermore, the inhibitory effects on motility of mouse isolated intestine tissue of the above mentioned compounds and other thirteen iridoid- and secoiridoid-type monoterpenes (7-10,13-16,18,19, 21, 22, and 25) previously obtained in the plant were analyzed. As results, new compound 5, some secoiridoid-type monoterpenes 7,10, 12-14,16, and 17, as well as 7-O-9′-type lignans 31 and 32 displayed significant inhibitory effect on contraction tension at 40 μM.
- Ding, Zhijuan,Liu, Yanxia,Ruan, Jingya,Yang, Shengcai,Yu, Haiyang,Chen, Meiling,Zhang, Yi,Wang, Tao
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- Sucrose derivatives, preparation method of same, and application thereof as anti-cancer medicine
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The invention relates to the technical field of medicines, and particularly provides a series of new-structure sucrose derivatives, on which hydroxyl groups are esterified by isovaleric acid, and a preparation method of same, and an application of the sucrose derivatives in preparation of anti-cancer medicines. The sucrose derivative is separated from a Compositae Ainsliaea plant, Ainsliaea yunnanensis Franch. The chemical structure of the sucrose derivative is represented as the formula (I). The sucrose derivative has significant cytotoxic activity to human lung adenocarcinoma cell A549 and can be used for preparing anti-cancer medicines.
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-
Paragraph 0059; 0062
(2017/12/28)
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- CHIRAL BINUCLEAR METAL COMPLEXES FOR STEREOSELECTIVE GLYCOSIDE HYDROLYSIS OF SACCHARIDES
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Disclosed herein is a class of chiral binuclear metal complexes for stereoselective glycoside hydrolysis of saccharides, and more particular chiral binuclear transition metal complex catalysts that discriminate epimeric glycosides and α- and β-glycosidic bonds of saccharides in aqueous solutions at near physiological pHs. The chiral binuclear metal complexes include a Schiff-base-type ligand derived from a chiral diamino building block, and a binuclear transition metal core, each which can be varied for selectivity. The metal core is a Lewis-acidic metal ion, such as copper, zinc, lanthanum, iron and nickel. The Schiff-base may be a reduced or non-reduced Schiff-base derived from aliphatic linear, aliphatic cyclic diamino alcohols or aromatic aldehydes. The ligand can be a penta- or heptadentate ligand derived from pyridinecarbaldehydes, benzaldehydes, linear or cyclic diamines or diamino alcohols.
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-
Paragraph 0062; 0063; 0064
(2017/10/13)
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- Trifasciatosides A-J, steroidal saponins from Sansevieria trifasciata
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Four previously unreported steroidal saponins, trifasciatosides A-D (1-4), three pairs of previously undescribed steroidal saponins, trifasciatosides E-J (5a, b-7a, b) including acetylated ones, together with twelve known compounds were isolated from the n-butanol soluble fraction of the methanol extract of Sansevieria trifasciata. Their structures were elucidated on the basis of detailed spectroscopic analysis, including 1H-NMR, 13C-NMR, 1H-1H correlated spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond connectivity (HMBC), total correlated spectroscopy (TOCSY), nuclear Overhauser enhancement and exchange spectroscopy (NOESY), electrospray ionization-time of flight (ESI-TOF)-MS and chemical methods. Compounds 2, 4, and 7a, b exhibited moderate antiproliferative activity against HeLa cells.
- Teponno, Rémy Bertrand,Tanaka, Chiaki,Jie, Bai,Tapondjou, Léon Azefack,Miyamoto, Tomofumi
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p. 1347 - 1355
(2016/09/09)
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- Absolute configuration of menthene derivatives by vibrational circular dichroism
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The aerial parts of Ageratina glabrata afforded (-)-(3S,4R,5R,6S)-3,5,6-trihydroxy-1-menthene 3-O-β-d-glucopyranoside (1) and (-)-(3S,4S,6R)-3,6-dihydroxy-1-menthene 3-O-β-d-glucopyranoside (3). Acid hydrolysis of 1 yielded (+)-(1R,4S,5R,6R)-1,5,6-trihydr
- Pardo-Novoa, Julio C.,Arreaga-González, Héctor M.,Gómez-Hurtado, Mario A.,Rodríguez-García, Gabriela,Cerda-García-Rojas, Carlos M.,Joseph-Nathan, Pedro,Del Río, Rosa E.
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p. 2570 - 2579
(2016/11/09)
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- Glycosidase- and β-lactamase-like activity of dinuclear copper(II) patellamide complexes
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Prochloron, a blue-green algae belonging to ancient prokaryotes, produces, like other cyanobacteria, cyclic pseudo-peptides, which are also found in its obligate symbiont ascidiae (Lissoclinum patellum). Although research has focused for some time on the
- Comba, Peter,Eisenschmidt, Annika,Kipper, Nora,Schie?l, Jasmin
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- Binuclear copper(II) complexes discriminating epimeric glycosides and α- And β-glycosidic bonds in aqueous solution
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Two chiral binuclear copper(II) complexes were synthesized and characterized for the first time as efficient chemoselective catalysts for the hydrolysis of aryl glycosides and disaccharides in aqueous solution at near neutral pH. Under these conditions, discrimination of epimeric aryl α-glycopyranosides was observed by both 29-fold different reaction rates and 3-fold different proficiency of the catalyst. Additionally, large differentiation of the nature of α- and β-glycosidic bond in aryl glycosides as model compounds is apparent, but also noted in selected disaccharides. The influence of the chirality of the complexes and the role of the configuration of the carbohydrate upon interaction with the catalyst is discussed in detail. Lastly, a putative mechanism for the metal complex-catalyzed hydrolysis is derived from the experimental evidence pointing at deprotonation of the hydroxyl group at C-2 as a pre-requisite for glycoside hydrolysis.
- Striegler, Susanne,Fan, Qiu-Hua,Rath, Nigam P.
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p. 349 - 364
(2016/05/24)
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- Mechanism for the formation and growth of carbonaceous spheres from sucrose by hydrothermal carbonization
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We report a new three-step mechanism for the formation and growth of carbonaceous spheres by hydrothermal carbonization of saccharides using sucrose as a precursor material. Carbonaceous spheres with small diameters and narrow size distribution were synthesized via a rapid heating route, and a notable phenomenon of a sudden drop in the mean diameter of the carbonaceous spheres at low concentration with the extension of time was observed. The morphology, chemical structure of carbonaceous spheres and the chemical composition of residual solutions were analysed by field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FT-IR) and solution 13C nuclear magnetic resonance (NMR) respectively. Based on these results, evolution of solid products is clearly revealed. The formation contains two stages, and oversaturation of primary particles attributed to autocatalysis of fructose by the yielded acid (formic acid) results in the appearance of large amounts of carbonaceous spheres in the second stage of formation, which accounts for the sudden drop in mean diameter.
- Qi, Yujie,Zhang, Mu,Qi, Lin,Qi, Yang
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p. 20814 - 20823
(2016/03/04)
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- A separation-integrated cascade reaction to overcome thermodynamic limitations in rare-sugar synthesis
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Enzyme cascades combining epimerization and isomerization steps offer an attractive route for the generic production of rare sugars starting from accessible bulk sugars but suffer from the unfavorable position of the thermodynamic equilibrium, thus reducing the yield and requiring complex work-up procedures to separate pure product from the reaction mixture. Presented herein is the integration of a multienzyme cascade reaction with continuous chromatography, realized as simulated moving bed chromatography, to overcome the intrinsic yield limitation. Efficient production of D-psicose from sucrose in a three-step cascade reaction using invertase, D-xylose isomerase, and D-tagatose epimerase, via the intermediates D-glucose and D-fructose, is described. This set-up allowed the production of pure psicose (99.9%) with very high yields (89%) and high enzyme efficiency (300 g of D-psicose per g of enzyme).
- Wagner, Nina,Bosshart, Andreas,Failmezger, Jurek,Bechtold, Matthias,Panke, Sven
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supporting information
p. 4182 - 4186
(2015/04/14)
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- Novel highly oxygenated and B-ring-seco-ent-diterpene glucosides from the seeds of Prinsepia utilis
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Two novel highly oxygenated and one rare B-ring cleave ent-kaurane diterpene glucosides, named prinsoside A (1), B (2) and C (3), respectively, were isolated from an ethanolic extract of the seeds of Prinsepia utilis. To our knowledge, prinsoside B (2) was the most highly oxygenated ent-kaurane diterpene glucoside discovered in nature. Their structures were elucidated by various spectroscopic methods including 1D, 2D NMR and HR-ESI-MS analyses, with the absolute configurations clarified by CD measurements on their corresponding diterpenoid aglycones obtained by enzymatic hydrolysis with β-glucosidase. Compounds 1-3 exhibited weak α-glucosidase inhibitory activities.
- Zhang, Qiao,Liu, Hong-Xin,Tan, Hai-Bo,Qiu, Sheng-Xiang
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p. 9415 - 9419
(2015/11/18)
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- Reconsidering the activation entropy for anomerization of glucose and mannose in water studied by NMR spectroscopy
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The anomerization of monosaccharides is a very important process to understand how their stereoisomers are stabilized in aqueous solutions. For glucose and mannose, it has been known that α- and β-anomers of hexopyranose exist as the major components. In order to examine the anomerization pathway for glucose and mannose in aqueous solutions, it is indispensable to determine the thermodynamic parameters such as the activation energy, the activation Gibbs free energy (ΔG?), enthalpy (ΔH?), and entropy (ΔS?). Although several research groups reported these quantities in aqueous solution, they have still been controversial especially for ΔS?. In this paper, we employ 1H NMR spectroscopy for monitoring the population of both α- and β-anomers of glucose and mannose. The contribution of ΔS? to ΔG? for glucose in water is estimated to be ca. 30%, while that for mannose is 8.0%. The large difference in ΔS? suggests that the anomerization pathway is not the same for glucose and mannose.
- Kosaka, Ami,Aida, Misako,Katsumoto, Yukiteru
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p. 195 - 200
(2015/04/22)
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- Three new triterpene saponins from roots of Eryngium planum
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Saponin composition of the roots of Eryngium planum L. was investigated. Triterpene saponins found in E. planum and also present in Eryngium maritimum were different from those described previously in Eryngium campestre L. Three primary saponins were isol
- Kowalczyk, Mariusz,Masullo, Milena,Thiem, Barbara,Piacente, Sonia,Stochmal, Anna,Oleszek, Wies?aw
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p. 653 - 660
(2014/05/06)
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- Chemical constituents and their antibacterial and antifungal activity from the Egyptian herbal medicine Chiliadenus montanus
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Phytochemical investigations of the CH2Cl2/MeOH (1:1) extract of air-dried aerial parts of Chiliadenus montanus afforded eight metabolites, in addition to eight other previously reported compounds, of which two were isolated for the first time as free acids. Structures were established by spectroscopic methods, including HREIMS, 1H, 13C, DEPT, 1H-1H COSY, HMQC and HMBC NMR analysis. Antimicrobial activity against an array of common bacterial and fungal strains was measured via a colorimetric assay with minimal growth inhibition observed in the μg/mL range for one of the tested metabolites.
- Hegazy, Mohamed-Elamir F.,Matsuda, Hisashi,Nakamura, Seikou,Hussein, Taha A.,Yoshikawa, Masayuki,Paré, Paul W.
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p. 154 - 161
(2014/06/09)
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- Engineering the specificity of trehalose phosphorylase as a general strategy for the production of glycosyl phosphates
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A two-step process is reported for the anomeric phosphorylation of galactose, using trehalose phosphorylase as biocatalyst. The monosaccharide enters this process as acceptor but can subsequently be released from the donor side, thanks to the non-reducing nature of the disaccharide intermediate. A key development was the creation of an optimized enzyme variant that displays a strict specificity (99%) for β-galactose 1-phosphate as product. This journal is the Partner Organisations 2014.
- Chen, Chao,Van Der Borght, Jef,De Vreese, Rob,D'Hooghe, Matthias,Soetaert, Wim,Desmet, Tom
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p. 7834 - 7836
(2014/07/08)
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- Catalytic consequences of micropore topology, mesoporosity, and acidity on the hydrolysis of sucrose over zeolite catalysts
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The effects of zeolite micropore topology, mesoporosity, and acidity on the hydrolysis of polysaccharides were probed in reactions of sucrose over a variety of zeolite catalysts (FER, MFI, MOR, MWW, BEA, FAU, pillared MFI (PMFI), and pillared MWW (PMWW)). The measured rate of sucrose hydrolysis over microporous zeolites varied by a factor of ～100 following a trend of FER a factor of ～2 in comparison with the microporous MWW and MFI zeolites, which may result from the enhanced acid site accessibility and mitigated diffusion constraints. The examination on the effects of zeolite acidity on the hydrolysis of sucrose by employing MFI, PMFI, BEA, MWW, and FAU zeolites with a range of Si/Al ratios showed that a Si/Al ratio of ～70-150 provides a maximal rate constant per acid site in the catalysts. The measured activation energies of the catalytic reactions in all zeolites were similar. The measured entropies, however, increased abruptly with increasing micropore sizes of zeolites and slightly with increasing mesoporosity in the zeolites. The present study suggests that the hydrolysis of sucrose is driven primarily by the reaction entropies that are dominated consecutively by the micropore topology, acidity, and mesoporosity of the zeolite catalysts. the Partner Organisations 2014.
- He, Yao,Hoff, Thomas C.,Emdadi, Laleh,Wu, Yiqing,Bouraima, Judicael,Liu, Dongxia
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p. 3064 - 3073
(2014/08/18)
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- Furostanol saponins from the seeds of Allium cepa L.
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Allium cepa L. is one of the most widely cultivated and used plants. In addition to its bulb (onion), which is used as food in many cultures, the seeds of A. cepa L. are used as a traditional herbal medicine by the Uygur nationality in China to treat diarrhea and promote blood flow. In a bioactivity-screening, the ethanol extract of seeds of A. cepa L. showed inhibitory effects on protein tyrosine phosphatase 1B (PTP1B) enzyme, with 81.1% inhibition. Phytochemical investigation of the ethanol extract of red onion (Allium cepa L.) seeds led to the isolation of eight new furostanol saponins, named ceparosides E-L (1-8). Their structures were established using 1D and 2D NMR spectroscopy, mass spectrometry and chemical methods. Compounds 1-8 were screened for inhibitory effects on the PTP1B enzyme and cytotoxic activity against five human cells, including HCT-8, Bel-7402, BGC-823, A549 and A2780, but all were found to be inactive.
- Li, Chuang-Jun,Yuan, Ling,Ji, Teng-Fei,Yang, Jian-Bo,Wang, Ai-Guo,Su, Ya-Lun
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- Exploring the catalytic activity of new water soluble dinuclear copper(ii) complexes towards the glycoside hydrolysis
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Two water soluble dinuclear copper(ii) complexes of a new dinucleating ligand, H3phpda [H3phpda = N,N′-bis(2-pyridylmethyl)-2-hydroxy-1,3-propanediamine-N,N′-dipropionic acid] have been synthesized and characterized for the investiga
- Haldar, Shobhraj,Patra, Ayan,Bera, Manindranath
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p. 62851 - 62861
(2015/02/19)
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- Novel substrates for the measurement of endo-1,4-β-glucanase (endo-cellulase)
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A specific and sensitive substrate for the assay of endo-1,4-β- glucanase (cellulase) has been prepared. The substrate mixture comprises benzylidene end-blocked 2-chloro-4-nitrophenyl-β-cellotrioside (BzCNPG3) in the presence of thermostable β-glucosidase. Hydrolysis by exo-acting enzymes such as β-glucosidase and exo-β-glucanase is prevented by the presence of the benzylidene group on the non-reducing end d-glucosyl residue. On hydrolysis by cellulase, the 2-chloro-4-nitrophenyl-β-glycoside is immediately hydrolysed to 2-chloro-4-nitrophenol and free d-glucose by the β-glucosidase in the substrate mixture. The reaction is terminated and colour developed by the addition of a weak alkaline solution. The assay procedure is simple to use, specific, accurate, robust and readily adapted to automation. This procedure should find widespread applications in biomass enzymology and in the specific assay of endo-1,4-β-glucanase in general.
- McCleary, Barry V.,Mangan, David,Daly, Robin,Fort, Sébastien,Ivory, Ruth,McCormack, Niall
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- Method for Producing Scyllo-Inositol
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The disclosure provides a method of producing a scyllo-inositol or a new scyllo-inositol derivative in a one-step process, from ubiquitous and inexpensive raw materials. Also provided is a scyllo-inositol derivative bonded to saccharides such as glucose and similar.
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Paragraph 0188; 0189
(2015/01/06)
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- Hydrolysis of konjac glucomannan by Trichoderma reesei mannanase and endoglucanases Cel7B and Cel5A for the production of glucomannooligosaccharides
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In this paper we describe the enzymatic hydrolysis of konjac glucomannan for the production of glucomannooligosaccharides using purified Trichoderma reesei mannanase, endoglucanases EGI (Tr Cel7b) and EGII (Tr Cel5a). Hydrolysis with each of the three enzymes produced a different pattern of oligosaccharides. Mannanase was the most selective of the three enzymes in the hydrolysis of konjac mannan and over 99% of the formed oligosaccharides had mannose as their reducing end pyranosyl unit. Tr Cel5A hydrolysate shared similarities with mannanase and Tr Cel7B hydrolysates and the enzyme had the lowest substrate specificity of the studied enzymes. The hydrolysate of Tr Cel7B contained a series of oligosaccharides with non-reducing end mannose (M) and reducing end glucose (G) (MG, MMG, MMMG, and MMMMG). These oligosaccharides were isolated from the hydrolysate by size exclusion chromatography in relatively high purity (86-95%) and total yield (23% of substrate). The isolated oligosaccharides were characterized using acid hydrolysis and HPAEC-PAD (carbohydrate composition), HPLC-RI and HPAEC-MS (to determine the DP of purified oligosaccharides), enzymatic hydrolysis (determination of non-reducing end carbohydrate) and NMR (both 1D and 2D, to verify structure and purity of purified compounds). Hydrolysis of konjac mannan with a specific enzyme, such as T. reesei Cel7B or mannanase, followed by fractionation with SEC offers the possibility to produce glucomannooligosaccharides with defined structure. The isolated oligosaccharides can be utilised as analytical standards, for determination of bioactivity of oligosaccharides with defined structure or as substrates for defining substrate specificity of novel carbohydrate hydrolyzing enzymes.
- Mikkelson, Atte,Maaheimo, Hannu,Hakala, Terhi K.
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- Effect of increasing the common anion concentration on the acid hydrolysis of glycosides
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Acid hydrolysis of glycoside compounds, methyl α-and β-d-glucopyranosides, was accelerated when KCl or KBr was added to an HCl or HBr system, respectively, consisting of H2O or aqueous 1,4-dioxane. The proton activity and solvent dissociation power of the system were not changed by the addition of the salt. These results confirm our previous suggestion that Br- and Cl- directly participate in the hydrolysis reaction. The extent of participation of the anions was also estimated.
- Phan, Hung Duy,Yokoyama, Tomoya,Matsumoto, Yuji
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p. 223 - 239
(2013/08/23)
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- Solid phase synthesis of glycopeptides using Shoda's activation of unprotected carbohydrates
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An expedient and simple protocol to access S-linked glycopeptides by Fmoc SPPS using unprotected carbohydrates is reported. The utility of the method was demonstrated with the solid phase synthesis of a MUC1 fragment (20 mer) containing two glycosylation sites that were substituted with S-linked glycans. The Royal Society of Chemistry.
- Novoa, Alexandre,Barluenga, Sofia,Serba, Christelle,Winssinger, Nicolas
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supporting information
p. 7608 - 7610
(2013/09/02)
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- Direct microwave-assisted hydrothermal depolymerization of cellulose
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A systematic investigation of the interaction of microwave irradiation with microcrystalline cellulose has been carried out, covering a broad temperature range (150 → 270°C). A variety of analytical techniques (e.g., HPLC, 13C NMR, FTIR, CHN analysis, hydrogen-deuterium exchange) allowed for the analysis of the obtained liquid and solid products. Based on these results a mechanism of cellulose interaction with microwaves is proposed. Thereby the degree of freedom of the cellulose enclosed CH2OH groups was found to be crucial. This mechanism allows for the explanation of the different experimental observations such as high efficiency of microwave treatment; the dependence of the selectivity/yield of glucose on the applied microwave density; the observed high glucose to HMF ratio; and the influence of the degree of cellulose crystallinity on the results of the hydrolysis process. The highest selectivity toward glucose was found to be ～75% while the highest glucose yield obtained was 21%.
- Fan, Jiajun,De Bruyn, Mario,Budarin, Vitaliy L.,Gronnow, Mark J.,Shuttleworth, Peter S.,Breeden, Simon,Macquarrie, Duncan J.,Clark, James H.
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supporting information
p. 12728 - 12731
(2013/09/02)
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