New ingenane diterpenoids from Euphorbia kansui reverse multi-drug resistance

Ten ingenane-type diterpenoids, including two undescribed compounds named as kansuininols A-B (1-2), were isolated from the roots of Euphorbia kansui. Their structures were elucidated by detailed interpretation of their spectroscopic data, especially 2D-NMR and HR-ESI-MS. Chemoreversal assays of these isolates were carried on adriamycin resistant human breast adenocarcinoma cell line MCF-7/ADR, and compounds 1-2 were identified as potent low-cytotoxic MDR modulators with greater chemoreversal ability than the positive drug verapamilti.