Unusual microbial lactonization and hydroxylation of asiatic acid by Umbelopsis isabellina

Abstract

Asiatic acid (1) is a natural triterpenoid isolated from Centella asiatica. This paper reports the microbial transformation of asiatic acid by an endophytic fungus Umbelopsis isabellina to obtain derivatives potentially useful for further studies. Incubation of asiatic acid with U. isabellina afforded two derivatives 2α,3β,7β, 23-tetrahydroxyurs-12-ene-28-oic acid (2) and 2α,3β,7β,23-tetrahydroxyurs-11-ene-28,13-lactone (3). The structures of these compounds were elucidated by spectral data. Compound 3 has formed an unusual lactone. These two products are new compounds. The possible transformation passway was also discussed.

Keywords::

• biotransformation
• asiatic acid
• Umbelopsis isabellina

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was financially supported by the National Natural Science Foundation of China [Grant number 21172267] and by the Program for Innovative Research Team in IMPLAD [Grant number IT1305].