Selective oxidation-reduction and esterification of asiatic acid by Pestalotiopsis microspora and anti-HCV activity. (March 2017)

• Record Type: Journal Article
• Authors: Gao, Zhao-Hui; Gao, Ran-Ran; Dong, Xin-Ran; Zou, Zhong-Mei; Wang, Qi; Zhou, De-Min; Sun, Di-An
• Is Part Of: Phytochemistry letters. Volume 19(2017:Mar.)
• Page Start: 108
• Page End: 113
• Publication Date: 2017-03
• Subjects: Asiatic acid -- Selective oxidation-reduction -- Esterification -- Pestalotiopsis microspora -- Anti-HCV activity; Botanical chemistry -- Periodicals; Chimie végétale -- Périodiques; 572.205
• DOI: 10.1016/j.phytol.2016.12.014
• Languages: English
• ISSNs: 1874-3900

Abstract

Graphical abstract: Highlights: Six derivatives were isolated from the fermented broth and five of them were new compounds. Some reactions, such as hydroxylation at saturated carbons, which were difficult to be achieved through chemical modification, were relatively easy in the microbial biotransformation. The reactions involved in the biotransformation of asiatic acid by Pestalotiopsis microspora were hydroxylation, oxidation, reduction and esterification. The possible biotransformation pathway was discussed. Four compounds showed slight inhibition of HCV pp infection. Abstract: Microbial transformation of asiatic acid (AA) by an endophytic fungus, Pestalotiopsis microspora, yielded six metabolites: 2-oxo-3β, 15α, 23-trihydroxyurs-12-ene-28-oic acid (1 ); 2-oxo-3β, 15α, 22α, 23-tetrahydroxyurs-12-ene-28-oic acid (2 ); 2-oxo-3β, 15α, 23, 30-tetrahydroxyurs-12-ene-28-oic acid (3 ); 2α, 3β, 15α, 23, 30-pentahydroxyurs-12-ene-28-oic acid methyl ester (4 ); 2α, 3α, 15α, 23-tetrahydroxyurs-12-ene-28-oic acid (5 ); 2α, 3α, 15α, 23, 30-pentahydroxyurs-12-ene-28-oic acid (6 ). The structure elucidation of these products was confirmed based on the spectroscopic data. Compounds 2–6 were new. A possible biotransformation pathway is proposed. The anti-HCV activity of compounds 1–6 was also evaluated.