Novel bioactive diterpenoids from Aframomum aulacocarpos

Three new labdane diterpenes, 12 alpha,17-epoxy-3 beta-hydroxy-8(9),13- labdadien-16,15-olide (aulacocarpinolide) [1], methyl 8 beta,17:14 zeta,15-diepoxy-3 beta-hydroxy- 12E-labden-16-oate (aulacocarpin A) [2], and methyl 8 beta,17:14 zeta,15-diepoxy-3 beta,6 beta- dihydroxy-12E-labden-16-oate (aulacocarpin B) [3] have been isolated from the Cameroonian spice, Aframomum aulacocarpos, and their structures elucidated using spectroscopic techniques. The known bioactive diterpene dialdehyde, 8 beta,17-epoxy-12E-labdene-15,16-dial (aframodial) [4] was also isolated. Compounds 1-3 showed weak antimicrobial and cytotoxic activities.