The unique structure, novel biological mechanism, and clinical importance of the antitumor agent paclitaxel has been attracting a great deal of interest in the isolation of structurally novel and biologically active taxanes from plants in the genus Taxus [1]. Since 1960s, extensive phytochemical studies have been carried out to isolate bioactive taxane diterpenoids from the plant materials of T. brevifolia, T. baccata, T. cuspidata, T. canadensis, T. chinensis, T. mairei, T. yunnanensis, and T.
