METHODS AND RESULTS:
Continued interest in cytotoxic alkaloids resulted in the isolation of 37 alkaloids including 29 known monoterpenoid indole alkaloids from the aerial parts of Tabernaemontana officinalis. Of the remaining 8 alkaloids, six were bisindole alkaloids named taberdivarine A, taberdivarine B, taberdivarine C, taberdivarine D, taberdivarine E, taberdivarine F (1-6) and the two were monomers named taberdivarine G and taberdivarine H (7-8).
CONCLUSIONS:
Alkaloids 1 and 2 are voaphylline-vobasinyl type bisindole alkaloids, a structural type previously unknown, while 3-6 exhibited cytotoxicity against three human cancer cell lines HeLa, MCF-7, and SW480 with IC50 values ranging from 1.42 to 11.35 μM. |