Isolation of gelsedine-type indole alkaloids from Gelsemium elegans and evaluation of the cytotoxic activity of Gelsemium alkaloids for A431 epidermoid carcinoma cells

Four new gelsedine-type indole alkaloids (1-4) were isolated from the leaves of Gelsemium elegans, together with 11 known alkaloids. The structures were determined as 14-acetoxygelsenicine (1), 14-acetoxy-15-hydroxygelsenicine (2), 14-hydroxy-19-oxogelsenicine (3), and 14-acetoxygelselegine (4), respectively, by spectroscopic analysis. The cytotoxic effects of 14 Gelsemium alkaloids including two new compounds (1, 2) were evaluated using the A431 human epidermoid carcinoma cell line. Of these, the gelsedine-type alkaloids 14-acetoxygelsenicine (1), 14,15-dihydroxygelsenicine (5), gelsedine (7), and gelsemicine (8) showed potent cytotoxic effects.