Cytotoxic monoterpenoid indole alkaloids from the aerial parts of Kopsia officinalis.

Three new monoterpenoid indole alkaloids, kopsiaofficines A-D (1-3), were isolated from the 95% EtOH extract of the aerial parts of Kopsia officinalis. Their structures were established on the basis of spectroscopic data. The isolated alkaloids were tested in vitro for cytotoxic activity against seven lung cancer cell lines. Consequently, alkaloids 1 and 3 exhibited some cytotoxic activities against all the tested tumor cell lines with IC₅₀ values less than 20 µM.