New approaches to the structural modification of olean-type pentacylic triterpenes via microbial oxidation and glycosylation

Site-selective biotransformation of ursane triterpenes by Streptomyces griseus ATCC 13273

“…Based on the HR-ESI-MS, 1D and 2D NMR data and the reaction types on ursolic acid, compound 2a was identied as 3-oxo-urs-12-en-28, 30-dioic acid; compound 2b was identied as 24-hydroxy-3-oxo-urs-12-en-28,30-dioic acid; 24 compound 3a was identied as 2a,3b-dihydroxy-urs-12-ene-28,30-dioic acid, and compound 3b was identied as 2a,3b,24-trihydroxy-urs-12ene-28,30-dioic acid (the structure elucidation can be seen in the ESI †). Biotransformation of asiatic acid (4, 100 mg) with S. griseus ATCC 13273 resulted in only one additional polar metabolite, 4a (52.1 mg, yield 49.1%) ( Fig.…”

“…18,19 In fact, when using microorganisms as a biocatalyst, the cheap and readily available compounds in nature can be directionally converted to high added-value natural compounds or new natural productlike compounds. [20][21][22] In our previous studies, some novel microbial transformations of pentacyclic triterpenoids such as asymmetric ketone hydroxylation 23 and methyl hydroxylation 24 have been reported individually. Streptomyces griseus ATCC 13273 has been proven as a potent strain that can achieve oxygenation of unactivated C-H bonds of the olean-type pentacyclic triterpenes.…”

“…Streptomyces griseus ATCC 13273 has been proven as a potent strain that can achieve oxygenation of unactivated C-H bonds of the olean-type pentacyclic triterpenes. 24 In order to investigate the regioselective oxidizing capability of S. griseus ATCC 13273 to ursane triterpenes and expand the structural diversities of PTs, ve ursane triterpenes, ursolic acid (1), 3-oxo ursolic acid (2), corosolic acid (3), asiatic acid (4) and madasiatic acid (5), were used as the substrates in this study, resulting in eight new metabolites and one known metabolite. This was the rst time the biotransformation of ursane triterpenes by S. griseus ATCC 13273 was screened.…”

Microbial-Catalyzed Biotransformation of Multifunctional Triterpenoids Derived from Phytonutrients

“…These highly efficient and regioselective methyl oxidation and glycosylation provided an alternative approach to expand the structural diversity of OPTs [38]. The two interesting reactions observed during fermentation of four synthetic pentacyclic triterpenoids ( 3 – 4 ) with S. griseus ATCC 13273 and A. ochraceus CICC 40330, are the the regio-selective oxidation of the methyl group on C-4 and C-20 and the formation of glycosyl ester of C-28 carboxyl group.…”

Antimicrobial Activity of two Semisynthetic Triterpene Derivatives from Euphorbia Officinarum Latex Against Fungal and Bacterial Phytopathogens

“…However, a preliminary study of the antimicrobial activity of lupeol acetate, 31-norlanostenol and euphorbol against several fungal and bacterial phytopathogens did not show any noticeable activity. Several studies reported that modification of triterpenes through enzymatic or chemical synthesis often resulted in enhanced biological activities [12][13][14][15][16]. In this study we attempted to enhance the activity of lupeol acetate and 31-norlanostenol through chemical modification.…”