609-06-3Relevant academic research and scientific papers
Steroidal glycosides from the underground parts of Hosta ventricosa and their anti-inflammatory activities in mice
Chu, Hong-Biao,Li, Nan-Nan,Zhang, Zong-Ping,Hu, Xiao-Yue,Yu, Cai-Yun,Hua, Lei
, p. 1766 - 1774 (2019/07/16)
Two new pregnane glycosides, 2α, 3β-dihydroxy-5α-pregn-16-en-20-one-3-O-{α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-β-D-galactopyranoside} (1) and 2α, 3β-dihydroxy-5α-pregn-16-en-20-one-3-O-{β-D-glucopyranosyl-(1→2)-[β-D-xylopyranosyl-(1→3)]-β-D-glucopyranosyl-(1→4)-β-D-galactopyranoside}(2), have been isolated along with two known spirostanol saponins from the underground parts of Hosta ventricosa. Their structures were elucidated on the basis of chemical and spectral evidence. The anti-inflammatory activities of these steroidal glycosides were evaluated using a xylene-induced ear edema model. Our results indicated that the compounds exhibited promising anti-inflammatory activities.
Electrochemical Activation of Galactose Oxidase: Mechanistic Studies and Synthetic Applications
Fryszkowska, Anna,Klapars, Artis,Marshall, Nicholas,Ruccolo, Serge,Strotman, Neil A.,Zhang, Shaoguang
, p. 7270 - 7280 (2021/06/30)
The enzyme galactose oxidase (GOase) is a copper radical oxidase that catalyzes the aerobic oxidation of primary alcohols to the aldehydes and has been utilized to that end in large-scale pharmaceutical processes. To maintain its catalytic activity and ensure high substrate conversion, GOase needs to be continuously (re)activated by 1e- oxidation of the constantly formed out-of-cycle species (GOasesemi) to the catalytically active state (GOaseox). In this work, we report an electrochemical activation method for GOase that replaces the previously used expensive horseradish peroxidase activator in a GOase-catalyzed oxidation reaction. First, the formation of GOaseox of a specifically engineered variant via nonenzymatic oxidation of GOasesemi was studied by UV-vis spectroscopy. Second, electrochemical oxidation of GOase by mediators was studied using cyclic voltammetry. The electron-transfer rates between GOase and various mediators at different pH values were determined, showing a dependence on both the redox potential of the mediator and the pH. This observation suggests that the oxidation of GOase by mediators at pH 7-9 likely occurs via a concerted proton-coupled electron-transfer (PCET) mechanism under anaerobic conditions. Finally, this electrochemical GOase activation method was successfully applied to the development of a bioelectrocatalytic GOase-mediated aerobic oxidation of benzyl alcohol derivatives, cinnamyl alcohol, and aliphatic polyols, including the desymmetrizing oxidation of 2-ethynylglycerol, a key step in the biocatalytic cascade used to prepare the promising HIV therapeutic islatravir.
A novel acid polysaccharide from Boletus edulis: extraction, characteristics and antitumor activities in vitro
Meng, Ting,Yu, Sha-sha,Ji, Hai-yu,Xu, Xiao-meng,Liu, An-jun
, p. 13 - 24 (2021/02/01)
A novel cold-water-soluble polysaccharide (BEP), with a molecular weight of 6.0 × 106?Da, was isolated from Boletus edulis. BEP consists of galactose, glucose, xylose, mannose, glucuronic, and galacturonic acid in a ratio of 0.34:0.28:0.28:2.57:1.00:0.44. The IR results showed that BEP was an acid polysaccharide, containing α-type and β-type glucoside bonds. MTT assay showed BEP could inhibit cell proliferation significantly. Morphological observation demonstrated that BEP-treated MDA-MB-231 and Ca761 cells exhibited typical apoptotic morphological features. Flow cytometry analysis revealed that BEP caused mitochondrial membrane potential collapse. Annexin V-FITC/PI staining indicated that BEP induced apoptosis of MDA-MB-231 and Ca761 cells through cell block in S phase and G0/G1 phase, respectively. Western blot results showed that BEP could increase the Bax/Bcl-2 ratios, promote the release of cytochrome C, and activate the expression of caspase-3 and caspase-9 in MDA-MB-231 and Ca761 cells. In conclusion, our results demonstrated that BEP could inhibit the proliferation of breast cancer cells and induce apoptosis through mitochondrial pathways.
Kinetics and mechanism of quinolinium dichromate mediated oxidation of sugar alcohols in Bronsted acid media
Kodali, Satish Babu,Jakku, Narendar Reddy,Kamatala, Chinna Rajanna,Yerraguntla, Rajeshwar Rao
, p. 167 - 177 (2019/12/27)
Bronsted acid catalyzed oxidation of certain sugar alcohols (polyols) has been studied by quinolinium dichromate (QDC) using aqueous sulfuric, perchloric, and hydrochloric acids at different temperatures. At constant acidity, reaction kinetics revealed the second-order kinetics with a first order in [Alcohol] and [QDC]. Zucker-Hammett, Bunnett, and Bunnett-Olsen criteria were used to analyze acid-dependent rate accelerations. Bunnett-Olsen plots of (log k + Hν) versus (Hν + log [H+]), and (log k) versus (Hν + log [H+]) afforded slope values (? and ?*, respectively)?>?0.47, suggesting that a water molecule acts as a prton transfer agent in the slow step of the mechanism in the oxidation of alcohols by QDC in the presence of aqueous sulfuric, perchloric, and hydrochloric acids.
Antiproliferative activity of new pentacyclic triterpene and a saponin from: Gladiolus segetum Ker-Gawl corms supported by molecular docking study
Abd El-Kader, Adel M.,Abdelmohsen, Usama Ramadan,Hajjar, Dina,Hayallah, Alaa M.,Mahmoud, Basma Khalaf,Mohamed, Mamdouh F. A.
, p. 22730 - 22741 (2020/07/03)
A new triterpenoidal saponin identified as 3-O-[β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 4)-β-d-xylopyranosyl]-2β,3β,16α-trihydroxyolean-12-en-23,28-dioic acid-28-O-α-l-rhamnopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 2)-α-l-arabinopyranoside 1 together with a new oleanane triterpene identified as 2β,3β,13α,22α-tetrahydroxy olean-23,28-dioic acid 2 and 6 known compounds (3-8) have been isolated from Gladiolus segetum Ker-Gawl corms. The structural elucidation of the isolated compounds was confirmed using different chemical and spectroscopic methods, including 1D and 2D NMR experiments as well as HR-ESI-MS. Moreover, the in vitro cytotoxic activity of the fractions and that of the isolated compounds 1-8 were investigated against five human cancer cell lines (PC-3, A-549, HePG-2, MCF-7 and HCT-116) using doxorubicin as a reference drug. The results showed that the saponin fraction exhibited potent in vitro cytotoxic activity against the five human cancer cell lines, whereas the maximum activity was exhibited against the PC-3 and A-549 cell lines with the IC50 values of 1.13 and 1.98 μg mL-1, respectively. In addition, compound 1 exhibited potent activity against A-549 and PC-3 with the IC50 values of 2.41 μg mL-1 and 3.45 μg mL-1, respectively. Interestingly, compound 2 showed the maximum activity against PC-3 with an IC50 of 2.01 μg mL-1. These biological results were in harmony with that of the molecular modeling study, which showed that the cytotoxic activity of compound 2 might occur through the inhibition of the HER-2 enzyme.
Chemical synthesis method of L-xylose
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Paragraph 0068-0070, (2018/11/22)
The invention discloses a novel chemical synthesis method of L-xylose. According to the novel chemical synthesis method, 2, 2-dimethoxypropane protects hydroxyl of L-(-)2,3-dihydroxypropionaldehyde, and then a product is coupled with (1-bromovinyl)trimethylsilane so as to establish a basic framework of a target product; after production of 99% of ee is guaranteed by a sharpless epoxidation or Jacobsen-Katsuki expoxidation method, a three-membered ring is opened by protecting groups to guarantee that the configuration thereof is unchanged; then, the hydroxyl group produced by selectively removing one protecting group is oxidized into an aldehyde group; finally, the remaining protecting groups are removed to obtain the target product L-xylose, and the total yield is 46-48%. By the novel chemical synthesis method, the condition is mild, raw materials are cheap and easy to obtain, and a synthesis thought and the synthesis method are provided for chemical synthesis of a series of aldoses.
Exploring the biocatalytic scope of alditol oxidase from Streptomyces coelicolor
Van Hellemond, Erik W.,Vermote, Linda,Koolen, Wilma,Sonke, Theo,Zandvoort, Ellen,Heuts, Dominic P. H. M.,Janssen, Dick B.,Fraaije, Marco W.
experimental part, p. 1523 - 1530 (2011/03/22)
The substrate scope of the flavoprotein alditol oxidase (AldO) from Streptomyces coelicolor A3(2), recombinantly produced in Escherichia coli, was explored. While it has been established that AldO efficiently oxidizes alditols to D-aldoses, this study revealed that the enzyme is also active with a broad range of aliphatic and aromatic alcohols. Alcohols containing hydroxy groups at the C-1 and C-2 positions like 1,2,4-butanetriol (Km=170 mM, k cat -4.4s-1), 1,2-pentanediol (Km=52 mM, k cat=0.85 s-1) and 1,2-hexanediol (Km=97 mM, kcat=2.0s-1) were readily accepted by AldO. Furthermore, the enzyme was highly enantioselective for the oxidation of 1,2-diols [e.g., for l-phenyl-1,2-ethanediol the (R)-enantiomer was preferred with an Is-value of 74]. For several diols the oxidation products were determined by GC-MS and NMR. Interestingly, for all tested 1,2-diols the products were found to be the a-hydroxy acids instead of the expected α-hydroxy aldehydes. Incubation of (R)-1-phenyl-1,2-ethanediol with 18O-labelled water (H 218O) revealed that a second enzymatic oxidation step occurs via the hydrate product intermediate. The relaxed substrate specificity, excellent enantioselectivity, and independence of coenzymes make AldO an attractive enzyme for the preparation of optically pure 1,2-diols and α-hydroxy acids.
PROCESSES FOR THE PRODUCTION OF XYLITOL
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Page/Page column 26, (2008/06/13)
Methods of producing xylitol comprising the oxidative decarboxylation of a reactant substrate are provided herein. The oxidative decarboxylation is performed in one of two ways. In the first, the oxidative decarboxylation is performed by an electrochemical process, preferably an anodic odixative decarboxylation of a reactant substrate. In the second, the oxidative decarboxylation of the reactant substrate is carried out by a series of oxidation-reduction chemical reactions.
Phenylpropanoid glucosides from leaves of Coussarea hydrangeifolia (Rubiaceae)
Hamerski, Lidilhone,Bomm, Mauro Dionei,Silva, Dulce Helena Siqueira,Young, Maria Claudia Marx,Furlan, Maysa,Eberlin, Marcos Nogueira,Castro-Gamboa, Ian,Cavalheiro, Alberto Jose,Da Silva Bolzani, Vanderlan
, p. 1927 - 1932 (2007/10/03)
Phenylpropanoid glycosides, 1′-O-benzyl-α-l-rhamnopyranosyl- (1″ → 6′)-β-d-glucopyranoside (1) and α-l- xylopyranosyl-(4″ → 2′)-(3-O-β-d-glucopyranosyl)-1′- O-E-caffeoyl-β-d-glucopyranoside (2), together with the known derivatives, 1,6-di-O-caffeoyl-β-d-glucopyranoside (3), 1-O-(E)-caffeoyl-β-d- glucopyranoside (4) and 1-O-(E)-feruloyl-β-d-glucopyranoside (5), were isolated from leaves of Coussarea hydrangeifolia. Their structures were determined by IR, HRESIMS, and 1D and 2D NMR experiments, and their antioxidant activities, evaluated by assaying the free radical scavenging capacity using the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical as substrate. The antioxidant activities of 3 and 4 (IC50 values of 15.0 and 19.2 μM, respectively) were comparable to that of the standard positive control caffeic acid, whilst 2 and 5 were only weakly active and 1 was inactive.
L-Ribose: An easily prepared rare sugar
Angyal, Stephen J.
, p. 58 - 59 (2007/10/03)
A method to synthesize L-ribose was described by molybdate-catalyzed epimerization of the readily available L-arabinose. The synthesis is one-step and except for a catalytic amount of molybdic acid do not require any expensive reagents, while the solvents used are water and a small amount of methanol. The process can be carried out in 2-3 days. Although the yield of L-ribose is only 20%, being in equilibrium with arabinose, most of the unreacted arabinose is recoverable and can be used again.
