A new sesquiterpene ester from Celastrus orbiculatus reversing multidrug resistance in cancer cells.

In a search for revertants of multidrug-resistance in cancer cells, a novel (1) and two known (2,3) sesquiterpene esters were isolated from the root of Celastrus orbiculatus. The structure of 1 was elucidated as 1 beta,2 beta-diacetoxy-6 alpha,9 alpha-bis(benzoyloxy)dihydro-beta-agarofuran. Compounds 1-3 partially or completely reversed resistance to adriamycin, vinblastine, and paclitaxel of multidrug-resistant KB-V1 and MCF7/ADR cells.