501-16-6Relevant articles and documents
Detailed mechanism of phenol-inhibited peroxidase-catalyzed oxidation of indole-3-acetic acid at neutral pH
Krylov, Sergey N.,Dunford, H. Brian
, p. 735 - 741 (1996)
The inhibition of horseradish peroxidase (HRP)-catalyzed oxidation of indole-3-acetic acid (IAA) by a phenol, caffeic acid (CA), was studied using both a kinetic approach and computer simulation. The presence of CA resulted in a lag period in IAA oxidation. The lag period increased slowly with increasing [CA] until a critical concentration, [CA]cr, was reached, then it increased much faster when [CA] was greater than [CA]cr The [CA]cr was proportional to [IAA] and did not depend upon [HRP]. Caffeic acid was oxidized by compound I and compound II of HRP with bimolecular rate constants (6.8 ± 107 and 2.1 ± 107 M-1s-1), which were much higher than the corresponding rate constants for IAA oxidation (2.3 ± 103 and 2.0 ±102 M-1s-1). Our experimental data show that CA inhibits IAA oxidation because it is able to compete effectively as a peroxidase substrate. A model based on a detailed mechanism of IAA oxidation was investigated using computer simulation. A rate constant driving nonenzymatic hydroperoxide formation in IAA solution was determined, 3.0 × 10-7 s-1. The model quantitatively describes the experimental results of this work and also qualitatively explains data published earlier. The critical inhibitor concentration is approximately equal to twice the concentration of hydroperoxide in IAA solution at the time of inhibitor addition. Therefore hydroperoxide concentration can be calculated from the determination of critical inhibitor concentration.
Engineered Bacterial Flavin-Dependent Monooxygenases for the Regiospecific Hydroxylation of Polycyclic Phenols
Dippe, Martin,Funke, Evelyn,Herrmann, Susann,Pecher, Pascal,Pietzsch, Markus,Wessjohann, Ludger A.
, (2022/02/19)
4-Hydroxyphenylacetate 3-hydroxylase (4HPA3H), a flavin-dependent monooxygenase from E. coli that catalyzes the hydroxylation of monophenols to catechols, was modified by rational redesign to convert also more bulky substrates, especially phenolic natural products like phenylpropanoids, flavones or coumarins. Selected amino acid positions in the binding pocket of 4HPA3H were exchanged with residues from the homologous protein from Pseudomonas aeruginosa, yielding variants with improved conversion of spacious substrates such as the flavonoid naringenin or the alkaloid mimetic 2-hydroxycarbazole. Reactions were followed by an adapted Fe(III)-catechol chromogenic assay selective for the products. Especially substitution of the residue Y301 facilitated modulation of substrate specificity: introduction of nonaromatic but hydrophobic (iso)leucine resulted in the preference of the substrate ferulic acid (having a guaiacyl (guajacyl) moiety, part of the vanilloid motif) over unsubstituted monophenols. The in vivo (whole-cell biocatalysts) and in vitro (three-enzyme cascade) transformations of substrates by 4HPA3H and its optimized variants was strictly regiospecific and proceeded without generation of byproducts.
Photoinduced Regioselective Olefination of Arenes at Proximal and Distal Sites
Ali, Wajid,Anjana, S. S.,Bhattacharya, Trisha,Chandrashekar, Hediyala B.,Goswami, Nupur,Guin, Srimanta,Maiti, Debabrata,Panda, Sanjib,Prakash, Gaurav,Saha, Argha,Sasmal, Sheuli,Sinha, Soumya Kumar
supporting information, p. 1929 - 1940 (2022/02/01)
The Fujiwara-Moritani reaction has had a profound contribution in the emergence of contemporary C-H activation protocols. Despite the applicability of the traditional approach in different fields, the associated reactivity and regioselectivity issues had
Herbicide based on haloxyfop, flumetsulam and halosulfuron-methyl
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Paragraph 0038; 0046; 0053; 0061; 0068; 0076, (2021/06/21)
The invention discloses a herbicide based on haloxyfop, flumetsulam and halosulfuron-methyl. The herbicide is prepared from the following raw materials in parts by weight: 1-15 parts of haloxyfop-R-methyl, 1-15 parts of flumetsulam, 1-37 parts of halosulfuron-methyl, 1-2 parts of a modified antioxidant, 10-12 parts of borax, 6-8 parts of a surfactant, 10-12 parts of triethanolamine, 10-12 parts of vegetable oil and 40-42 parts of deionized water. After the haloxyfop-R-methyl, the flumetsulam and the halosulfuron-methyl are mixed, the effects are complementary, the weeding spectrum is wider, the weeding activity is high, the weeding effect is more excellent. In addition, the modified antioxidant is added into the herbicide formula, so that the composite herbicide has the effects of resisting oxidation aging and ultraviolet aging, effective components are prevented from decomposing and losing efficacy in the presence of light, the pesticide effect is kept lasting, and the application prospect and popularization value are remarkably improved.
Anti-inflammatory glycosides from the roots of Paeonia intermedia C. A. Meyer
Yu, Liang,Zhu, Ling-Juan,Wang, An-Hua,Qin, Yu,Zhang, Xue,Jia, Jing-Ming,Yao, Xin-Sheng
, p. 1452 - 1458 (2019/08/30)
Three new phenolic glycosides, intermedia A–C (1–3), one new acyclic alcohol glycoside, intermedia D (4), together with 3 known glycosides (5–7), were isolated from the dried roots of Paeonia intermedia C. A. Meyer. Their structures were established by means of extensive spectroscopic analysis (HRESIMS, NMR). Compound 1 have a rare benzo[1,5]dioxepine skeleton. The bioassay results showed that compound 3 exhibited inhibitory activity against proinflammatory cytokines nitric oxide (NO) secretion in LPS-activated RAW264.7 cells with an IC50 value of 85.76 ± 1.36 μM.
Optimization of the biosynthesis of b-ring ortho-hydroxy lated flavonoids using the 4-hydroxyphenylacetate 3-hydroxylase complex (Hpabc) of escherichia coli
Chen, Yang,Gao, Liping,Gui, Lin,Guo, Lina,Lei, Ting,Li, Yan,Ma, Xiubing,Ruan, Haixiang,Wang, Longji,Wang, Yunsheng,Xia, Tao
, (2021/05/31)
Flavonoids are important plant metabolites that exhibit a wide range of physiological and pharmaceutical functions. Because of their wide biological activities, such as anti-inflammatory, antioxidant, antiaging and anticancer, they have been widely used in foods, nutraceutical and pharmaceuticals industries. Here, the hydroxylase complex HpaBC was selected for the efficient in vivo production of ortho-hydroxylated flavonoids. Several HpaBC expression vectors were constructed, and the corresponding products were successfully detected by feeding naringenin to vector-carrying strains. However, when HpaC was linked with an S-Tag on the C terminus, the enzyme activity was significantly affected. The optimal culture conditions were determined, including a substrate concentration of 80 mg·L?1, an induction temperature of 28?C, an M9 medium, and a substrate delay time of 6 h after IPTG induction. Finally, the efficiency of eriodictyol conversion from P2&3-carrying strains fed naringin was up to 57.67 ± 3.36%. The same strategy was used to produce catechin and caf-feic acid, and the highest conversion efficiencies were 35.2 ± 3.14 and 32.93 ± 2.01%, respectively. In this paper, the catalytic activity of HpaBC on dihydrokaempferol and kaempferol was demonstrated for the first time. This study demonstrates a feasible method for efficiently synthesizing in vivo B-ring dihydroxylated flavonoids, such as catechins, flavanols, dihydroflavonols and flavonols, in a bacterial expression system.
Thiols Act as Methyl Traps in the Biocatalytic Demethylation of Guaiacol Derivatives
Grimm, Christopher,Kroutil, Wolfgang,Pompei, Simona,Schiller, Christine,Schober, Lukas
supporting information, p. 16906 - 16910 (2021/07/02)
Demethylating methyl phenyl ethers is challenging, especially when the products are catechol derivatives prone to follow-up reactions. For biocatalytic demethylation, monooxygenases have previously been described requiring molecular oxygen which may cause oxidative side reactions. Here we show that such compounds can be demethylated anaerobically by using cobalamin-dependent methyltransferases exploiting thiols like ethyl 3-mercaptopropionate as a methyl trap. Using just two equivalents of this reagent, a broad spectrum of substituted guaiacol derivatives were demethylated, with conversions mostly above 90 %. This strategy was used to prepare the highly valuable antioxidant hydroxytyrosol on a one-gram scale in 97 % isolated yield.
Acylated pelargonidin and cyanidin 3-sambubiosides from the flowers of Aeschynanthus species and cultivars
Iwashina, Tsukasa,Mizuno, Takayuki,Rahayu, Sri,Sugahara, Kohtaro,Tsutsumi, Chie,Widyatmoko, Didik
, (2021/10/01)
Thirteen anthocyanins were isolated from the flowers of two Aeschynanthus species, A. fulgens and A. pulcher, and six cultivars, ‘Mahligai’, ‘Mona Lisa’, ‘SoeKa’, ‘Redona’, ‘Freshya’ and ‘Bravera’, and identified as pelargonidin and cyanidin 3-O-sambubiosides and their malonates, succinates, p-coumarates and caffeates, and pelargonidin 3-O-glucoside by acid hydrolysis, HR-MS and NMR. Of their anthocyanins, pelargonidin 3-O-[xylosyl-(1 → 2)-(6''-malonylglucoside)] (2), pelargonidin 3-O-[xylosyl-(1 → 2)-(6''-succinylglucoside)] (3), pelargonidin 3-O-[xylosyl-(1 → 2)-(6''-E-p-coumaroylglucoside)] (4), pelargonidin 3-O-[xylosyl-(1 → 2)-(6''-Z-p-coumaroylglucoside)] (5), pelargonidin 3-O-[xylosyl-(1 → 2)-(6''-E-caffeoylglucoside)] (6) and cyanidin 3-O-[xylosyl-(1 → 2)-(6''-succinylglucoside)] (9) were reported in nature for the first time.
Ballodiolic acid a and b: Two new ros, (? oh), (onoo? ) scavenging and potent antimicrobial constituents isolated from ballota pseudodictamnus (l.) benth.
Ahmad, Ijaz,Ahmad, Nisar,Alobaid, Abdulrahman,Amin, Syed Badar,Bari, Ahmed,Fozia,Mahmood, Hafiz Majid,Shaheen, Asmat,Sohaib, Muhammad,Ullah, Riaz
, (2021/04/07)
Bioassays guided phytochemical investigations on the ethyl acetate-soluble fraction of the root material of Ballota pseudodictamnus (L.) Benth. led to the isolation of two new compounds, ballodiolic acid A (1) and ballodiolic acid B (2), along with three known compounds ballodiolic acid (3), ballotenic acid (4), and β-amyrin (5), which were also isolated for the first time from this species by using multiple chromatographic techniques. The structures of the compounds (1–5) were determined by modern spectroscopic analysis including 1D and 2D NMR techniques and chemical studies. In three separate experiments, the isolated compounds (1–5) demonstrated potent antioxidant scavenging activity, with IC50 values ranging from 07.22–34.10 μM in the hydroxyl radical (? OH) inhibitory activity test, 58.10–148.55 μM in the total ROS (reactive oxygen species) inhibitory activity test, and 6.23–69.01 μM in the peroxynitrite (ONOO? ) scavenging activity test. With IC50 values of (07.22 ± 0.03, 58.10 ± 0.07, 6.23 ± 0.04 μM) for? OH, total ROS, and scavenge ONOO?, respectively, ballodiolic acid B (2) showed the highest scavenging ability. Antibacterial and antifungal behaviors were also exposed to the pure compounds 1–5. In contrast to compounds 4 and 5, compounds 1–3 were active against all bacterial strains studied, with a good zone of inhibition proving these as a potent antibacterial agent. Similarly, compared to compounds 3–5, compounds 1 and 2 with a 47 percent and 45 percent respective inhibition zone were found to be more active against tested fungal strains.
Iron-catalyzed domino decarboxylation-oxidation of α,β-unsaturated carboxylic acids enabled aldehyde C-H methylation
Gong, Pei-Xue,Xu, Fangning,Cheng, Lu,Gong, Xu,Zhang, Jie,Gu, Wei-Jin,Han, Wei
supporting information, p. 5905 - 5908 (2021/06/18)
A practical and general iron-catalyzed domino decarboxylation-oxidation of α,β-unsaturated carboxylic acids enabling aldehyde C-H methylation for the synthesis of methyl ketones has been developed. This mild, operationally simple method uses ambient air as the sole oxidant and tolerates sensitive functional groups for the late-stage functionalization of complex natural-product-derived and polyfunctionalized molecules.
