Taxoids and abietanes from callus cultures of Taxus cuspidata.

Seventeen known taxoids and 10 abietanes were isolated from the dark brown callus culture of Taxus cuspidata cultivated on a modified Gamborg's B5 medium with 0.5 or 1.0 mg/L NAA. Seven known taxoids and four abietanes were obtained from the callus culture incubated under light irradiation on the medium with 1.0 mg/L NAA. Eight taxoids and five abietanes were also separated from the callus culture on the medium with 10 mmol/L beta-cyclodextrin and 1.0 mg/L NAA. The new compounds were identified by analyses of the spectroscopic data and were found to be abieta-6,8,11,13-tetraene-3beta,12-diol (1), 3beta,20-epoxy-12-methoxy-abieta-8,11,13-triene-3alpha,11-diol (2), 3alpha-hydroxy-9(10-->20)abeo-abieta-1,5,8,10(20),13-pentaene-7,11,12-trione (3), 2-hydroxy-9(10-->20)abeo-abieta-1,5,8,10(20),13-pentaene-3,7,11,12-tetraone (4), and 3,7-dioxo-9(10-->20)abeo-12-norabieta-1,5,8,10(20),13-pentaene-11,13-lactone (5), respectively. The yield of paclitaxel and its analogues was markedly decreased in the calluses mentioned above compared with that of standard callus. Instead, abietanes and some taxoids related to biosynthesis of paclitaxel were produced. Taxusin (6) exhibited stronger MDR-reversing activity than verapamil toward 2780 AD tumor cells.