Anti-protozoal and structure-activity relationships of chemical constituents of Acridocarpus chloropterus Oliver (Malpighiaceae) from Tanzania
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Date
2013
Authors
Hassanali, Ahmed
Malebo, H. M.
Wenzler, T.
Cal, M.
Swaleh, Sauda M.
Machocho, Alex K.
Häussinger, D.
Dalsgaard, P.
Omolo, M. O.
Séquin, U.
Journal Title
Journal ISSN
Volume Title
Publisher
Universal Research Publications
Abstract
Chromatographic separation of Acridocarpus chloropterus extract led to the isolation and identification of five triterpenes: β-sitosterol (1), stigmasterol (2), friedelin (3), oleanolic acid (4), ursolic acid (5); and five flavonoids: apigenin (6), luteolin (7), vitexin (8), kaempferol (9) and quercetin (10). Quercetin (10) exhibited moderate in vitro anti-plasmodial activity (IC50 2.6+0.05 μg/ml) while the rest of compounds were inactive. Mild to weak in vitro anti-trypanosomal activity was observed in quercetin (10) (IC50 3.60+0.1 μg/ml), ursolic acid (5) (IC50 7.80+0.1 μg/ml) and apigenin (6) (IC50 9.0+0.1 μg/ml). Ursolic acid (5) exhibited strong in vitro anti-leishmanial activity (IC50 0.80+0.001 μg/ml) while oleanolic acid (4), apigenin (6), kaempferol (9) and quercetin (10) showed moderate to mild activity (2.10+0.1, 2.20+0.1, 5.90+ 0.1 and 3.5+0.2 μg/ml, respectively) whereas favorable selectivity was observed with all flavonoids. Structure-activity-relationship (SAR) comparison of the isolated triterpenoids confirmed that the hydroxyl group at C-3 together with C-23, C-25, C-26 and C-30 methyl groups, C-12/C-13 double bond, the C-28 carboxylic acid group, and H-20 in ursolic acid (5) and related compounds are all responsible for the strong anti-leishmanial activity. The 3-OH and 3′-OH in the apigenin (6) and related compounds are responsible for the strong anti-protozoal activity observed in the isolated flavonoids. The strong to moderate anti-leishmanial activity of the isolated triterpenes and flavonoids make them good candidates or templates for new anti-protozoal drug devel
Description
Keywords
Acridocarpus chloropterus, antiprotozoal, cytotoxicity, SAR, triterpenes, flavonoids
Citation
International Journal of Natural Products Research 2013; 3(4): 74-81