TRADITIONAL MEDICINAL-PLANTS OF THAILAND .23. CYTOTOXIC AND ANTIMALARIAL ALKALOIDS FROM THE TUBERS OF STEPHANIA-PIERREI

Biological evaluation of extracts prepared from the tubers of Stephani a pierrei revealed cytotoxic and antimalarial activity. During the cou rse of separation, two new aporphine alkaloids, (-)-asimilobine-2-O-be ta-D-glucoside [2] and (-)-nordicentrine [8], in addition to twenty-on e known isoquinoline alkaloids, were isolated. Each isolate was mainly for cytotoxic and antimalarial activities. It was found that the cyto toxicity of S. pierrei was mainly due to the presence of the aporphine alkaloids containing the 1,2-methylenedioxy group 3-10, whereas the a ntimalarial activity was attributed to the nonquaternary aporphine alk aloids 1, 3-10 and the tetrahydroprotoberberines possessing a phenolic functionality, 13-15, 18. None of the isolates showed a degree of sel ectivity comparable to that of antimalarial drugs such as chloroquine, quinine, mefloquine, and artemisinin. Comparison of the alkaloid cont ent of S. pierrei and Stephania erecta strongly suggested separate ide ntities for the two plants.