Gelsedine-type oxindole alkaloids from Gelsemium elegans and the evaluation of their cytotoxic activity.

Phytochemical investigation on the 70% EtOH extract of the leaves and branches of Gelsemium elegans resulted into the isolation of five new gelsedine-type oxindole alkaloids, gelseleganins A-E (1-5). The structures of the isolated compounds were established based on 1D and 2D (H-H COSY, HMQC, and HMBC) NMR spectroscopy, in addition to high resolution mass spectrometry. The isolated alkaloids were tested in vitro for cytotoxic potential against seven tumor cell lines. As a result, alkaloids 3 exhibited significant cytotoxic activities against all the tested tumor cell lines with IC values <10μM.