Terpenoid alkaloids of the Buxaceae family with potential biological importance

Devkota KP, Lenta BN, Fokou PA, Sewald N. Terpenoid alkaloids of the Buxaceae family with potential biological importance. NATURAL PRODUCT REPORTS. 2008;25(3):612-630.The plants of the family Buxaceae are widely used in traditional medicine and constitute rich sources of terpenoidal alkaloids. Compounds of this family have been the subject of numerous chemical and pharmacological studies over past decades because of their interesting biological activities such as cholinesterase inhibition, as well as antibacterial and antileishmanial activities. The chemical and biological properties of these alkaloids, including data relevant to straightforward structure determination and information on biosynthesis, are highlighted in this review, with 144 references being cited

Anthraquinones from the stem bark of Stereospermum zenkeri with antimicrobial activity

Lenta BN, Weniger B, Antheaume C, et al. Anthraquinones from the stem bark of Stereospermum zenkeri with antimicrobial activity. Phytochemistry. 2007;68(11):1595-1599.Two anthraquinones, zenkequinones A and B were isolated from the stem bark of Stereospermum zenkeri together with known sterequinone-F, p-coumaric acid, sitosterol-3-O-beta-D-glucopyranoside and 3 beta-hydroxyolean-12-en-28-O-beta-D-glucopyranoside. Their structures were established by spectroscopic methods. The antimicrobial activity of the isolated compounds was evaluated against six multiresistant strains of pathogens. Zenkequinone B showed the best antibacterial activity (MIC 9.50 mu g/ml) against gram-negative Pseudomonas aeruginosa. (c) 2007 Elsevier Ltd. All rights reserved

Microbial transformation of the steroidal alkaloid dictyophlebine by Rhizopus stolonifer

Devkota KP, Choudhary MI, Nawaz SA, et al. Microbial transformation of the steroidal alkaloid dictyophlebine by Rhizopus stolonifer. Chemical & Pharmaceutical Bulletin. 2007;55(4):682-684.The microbial transformation of a steroidal alkaloid, dictyophlebine (1) with Rhizopus stolonifer (ATCC 10404) afforded three oxidized metabolites 2-4. Compound 2 was found to be a new product. These metabolites were structurally characterized on the basis of modern spectroscopic techniques. Their inhibitory activity towards acetyl- and butyrylcholinesterase has been evaluated and the new product 2 has been found to be more potent than the parent compound and other metabolites