A new taxoid from a callus culture of Taxus cuspidata as an MDR reversal agent.

A new taxoid, 5alpha,13alpha-diacetoxy-10beta-cinnamoyloxy-4(20),11-taxadien-9alpha-ol (1) along with its 9,10-isomer, taxinine NN-11 (2) were isolated from the callus cultures of Taxus cuspidata. The structures were identified by the analyses of the spectral data and chemical method. Their in vitro cytotoxicity against 3 cell lines (HepG2, WI-38 and VA-13) and multidrug resistance (MDR) reversal activity toward 2780AD tumor cells were preliminarily evaluated, the low cytotoxicities and potent MDR reversal activities suggested that they might be good lead compounds of tumor MDR reversal agent.