China
Africa
Explore chapters and articles related to this topic
Anti-Cancer Agents from Natural Sources
Published in Rohit Dutt, Anil K. Sharma, Raj K. Keservani, Vandana Garg, Promising Drug Molecules of Natural Origin, 2020
Debasish Bandyopadhyay, Felipe Gonzalez
Hydroxybenzoic acids are produced by the shikimate (ester of shikimic acid) pathway in various plants, bacteria, and fungi. The pathway consists of seven enzymes: DAHP synthase, 3-dehydroquinate synthase, 3-dehydroquinate dehydratase, shikimate dehydrogenase, shikimate kinase, EPSP synthase, and chorismate synthase. Hydroxybenzoic acids’ core structure contains a C6-C1 skeleton with seven carbon molecules. Some hydroxybenzoic acids are gallic, ellagic, and syringic acids (Figure 5.10). Tannins are a subgroup of hydroxybenzoic acids and two kinds of tannins are found: hydrolyzable and non-hydrolyzable. Hydrolysable tannins usually contain a central carbohydrate moiety. Hydrolyzable tannins are complex and usually biosynthesized by the condensation of various flavans. Hydroxybenzoic acids that contain anticancer activity are Gallic, ellagic, and syringic acid. Two tannins viz. cuphiin D1 and Oenothein Bhave been reported to contain limited anticancer activities. Their mechanism of inhibition is unknown.
The Effects of Synthetic Phosphonates on Living Systems
Published in Richard L. Hilderbrand, The Role of Phosphonates in Living Systems, 2018
The mechanism of action of glyphosate is thought to be associated with the metabolism of aromatic amino acids. Studies by Jaworski125 indicated that phenylalanine biosynthesis was inhibited by glyphosate at the chorismate mutase or prephenate dehydratase steps and that certain aromatic amino acids could reverse those effects. Further studies126 using Escherichia coli indicated that the above enzymes were not affected but that aromatic amino acids would reverse the phytotoxic effect. Exogenous aromatic amino acids supplied to soybean (Glycine Max [L.] Merr. Hill) seedlings reversed the root growth inhibition slightly (10%) but significantly. Glyphosate had no effect on uptake or incorporation of these amino acids and did not substantially affect shikimate dehydrogenase activity in control or amino acid fed seedlings. Duke and Hoagland127 concluded that either the mechanism of action of glyphosate is not the inhibition of aromatic amino acid synthesis or that root fed amino acids are compartmentalized differently than endogenous amino acids. Aromatic amino acids will generally reverse effects of glyphosate on unicellular organisms or on cell cultures of higher plants, but have an equivocal effect in higher plants that are intact. Duke and Hoagland127 suggest that the chelation of divalent metal ion by glyphosate may be important. Ekanayake et al.128 observed effects of glyphosate on amino acid metabolism but did not examine possible mechanisms.
Synthesis, biological activity and molecular modelling studies of shikimic acid derivatives as inhibitors of the shikimate dehydrogenase enzyme of Escherichia coli
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2018
Dulce Catalina Díaz-Quiroz, César Salvador Cardona-Félix, José Luis Viveros-Ceballos, Miguel Angel Reyes-González, Franciso Bolívar, Mario Ordoñez, Adelfo Escalante
Shikimate dehydrogenase (SDH, E.C. 1.1.1.25), the fourth enzyme in the SA pathway catalyses the reversible reduction of 3-dehydroshikimate (DHS) to SA using NADPH as co-substrate. SDH is a member of an oxide-reductase family whose crystallographic structure in several organisms have been determined either in the apoenzyme form or binary and ternary complexes12. The shared three-dimensional fold consists of two α/β domains linked by a pair of α-helices, the substrate-binding site is mainly delineated by residues from the N-terminal domain whereas the cofactor binding site is comprising in the C-terminal domain that adopts a Rossmann fold. Functional and structural studies on SDH enzymes opened a platform for the development of SDH inhibitors as few reports exist compared to other enzymes of the SA pathway.
High prevalence of imipenem-resistant and metallo-beta-lactamase-producing Pseudomonas aeruginosa in the Burns Hospital in Tunisia: detection of a novel class 1 integron
Published in Journal of Chemotherapy, 2019
Sarra Chairat, Houssem Ben Yahia, Beatriz Rojo-Bezares, Yolanda Sáenz, Carmen Torres, Karim Ben Slama
The MLST was performed by amplification of seven housekeeping genes: acsA (acetyl coenzyme A synthetase), aroE (shikimate dehydrogenase), guaA (GMP synthase), mutL (DNA mismatch repair protein), nuoD (NADH dehydrogenase I chain C, D), ppsA (phosphoenol pyruvate synthase) and trpE (anthralite synthetase component I), and by bidirectional sequencing of the amplicons according to P. aeruginosa MLST database website (http://pubmlst.org/paeruginosa/) and as previously recommended.23