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Chemistry of Essential Oils
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Figure 6.8 shows some of the biosynthetic intermediates stemming from shikimic acid (4) and which are of importance in terms of generating materials volatile enough to be essential oil components. Elimination of one of the ring alcohols and reaction with phosphoenolpyruvate (1) gives chorismic acid (29) that can undergo an oxy-Cope reaction to give prephenic acid (30). Decarboxylation and elimination of the ring alcohol now gives the phenylpropionic acid skeleton. Amination and reduction of the ketone function gives the essential amino acid phenylalanine (31), whereas reduction and elimination leads to cinnamic acid (32). Ring hydroxylation of the latter gives the isomeric o- and p-coumaric acids, (33) and (34), respectively. Further hydroxylation gives caffeic acid (35) and methylation of this gives ferulic acid (36). Oxidation of the methyl ether of the latter and subsequent cyclization gives methylenecaffeic acid (37). In shikimate biosynthesis, it is often possible to arrive at a given product by different sequences of the same reactions, and the exact route used will depend on the genetic makeup of the plant.
Anti-inflammatory potential of pyocyanin in LPS-stimulated murine macrophages
Published in Immunopharmacology and Immunotoxicology, 2019
José Marreiro de Sales-Neto, É. A. Lima, L. H. A. Cavalcante-Silva, U. Vasconcelos, S. Rodrigues-Mascarenhas
Pseudomonas aeruginosa is a common Gram-negative rod responsible for a wide range of severe nosocomial infections, being often associated with individuals with immunodeficiency diseases, which include burns, human immunodeficiency virus, cystic fibrosis, and patients undergoing cancer chemotherapy [1]. Infections caused by P. aeruginosa can affect several body systems, such as central nervous system [2], respiratory tract [3], sensory system [4], urinary tract [5], and vascular system [6]. Throughout infection, P. aeruginosa releases several virulence factors that help pathogen, contributing to infection establishment and reestablishment. Some of these virulence factors are pigmented, such as pyoverdine (yellow-green), pyomelanin (brown-reddish), and pyocyanin (greenish-blue) [7,8]. Pyocyanin, also known as 5-methyl-1(5H)-phenazinone, is a redox-active, heterocyclic, nitrogen-containing compound belonging to the class of natural phenazines [9], representing the greater amount phenazine produced by P. aeruginosa and one of the more important virulence factor produced by this pathogen [10,11]. Pyocyanin is exclusively synthesized by P. aeruginosa from chorismic acid, which is converted by PhzA, PhzB, PhzC, PhzD, PhzE, PhzF, and PhzG enzymes into phenazine-1-carboxylic acid, and then into phenazine-1-carboxamide, 1-hydroxyphenazine, and 5-methylphenazine-1-carboxylic acid betaine by PhzH, PhzS, and PhzM enzymes, respectively. Next, 5-methylphenazine-1-carboxylic acid betaine is converted by PhzS enzyme into pyocyanin [12], being delivered via type II secretion system [9].
New insight into structure-activity of furan-based salicylate synthase (MbtI) inhibitors as potential antitubercular agents
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2019
Laurent R. Chiarelli, Matteo Mori, Giangiacomo Beretta, Arianna Gelain, Elena Pini, Josè Camilla Sammartino, Giovanni Stelitano, Daniela Barlocco, Luca Costantino, Margherita Lapillo, Giulio Poli, Isabella Caligiuri, Flavio Rizzolio, Marco Bellinzoni, Tiziano Tuccinardi, Stefania Villa, Fiorella Meneghetti
Recombinant M. tuberculosis MbtI was produced and purified as previously reported14. Enzyme activity was determined measuring the production of salicylic acid by a fluorimetric assay slightly modified from Vasan et al.12 Briefly, assays were performed at 37 °C in a final volume of 400 µL of 50 mM Hepes pH 7.5, 5 mM MgCl2, using 1–2 µM MbtI and the reactions were started by the addition of chorismic acid and monitored using a Perkin-Elmer LS3 fluorimeter (Ex. λ = 305 nm, Em. λ = 420 nm). Inhibition assays were performed in the presence of the compound at 100 µM (stock solution 20 mM in DMSO), at 50 µM chorismic acid. For significantly active compounds, IC50 and Ki values were determined. To verify that the compounds were not PAINs, their ability to inhibit MbtI activity was tested in the presence of 0.1 mg/mL of bovine serum albumin (BSA) or in the presence of 0.01% (v/v) Triton X-100 to confirm that they did not act as aggregate, and in the presence of 100 mM of 1,4-dithio-DL-threitol (DTT) to exclude an enzyme inhibition due to reaction with cysteines22.
A Review of the Anti-Cancer Potential of Murraya koenigii (Curry Tree) and Its Active Constituents
Published in Nutrition and Cancer, 2022
Aniqa Aniqa, Sarvnarinder Kaur, Shilpa Sadwal
Carbazole alkaloids have a tricyclic structure consisting of two benzene rings fused on either side of a five-membered nitrogen-containing ring. Unlike terpenoids, there is limited knowledge about the carbazole alkaloids, but it is considered to be started from shikimic acid, followed up by chorismic acid, isochorismic acid, anthranilic acid, and finally turned into quinolone. Further, from the MVA or MEP pathway derived prenyl pyrophosphate (PP) does the prenylation of quinolone to form 3-methylcarbazole finally (19). At later stages, this 3-methylcarbazole may undergo different modification steps to yield an array of carbazole alkaloids (Figure 2).