Antiproliferative Activity of Cardenolides Isolated from Streptocaulon juventas

Abstract

Sixteen cardenolides, two hemiterpenoids, two phenylpropanoids and a phenylethanoid isolated from the roots of Streptocaulon juventas (LOUR.) MERR. were examined for their antiproliferative activity toward three human-derived (HT-1080 fibrosarcoma, lung A549 adenocarcinoma, cervix HeLa adenocarcinoma) and three murine-derived (colon 26-L5 carcinoma, Lewis lung carcinoma, B16-BL6 melanoma) cell lines. The cardenolides selectively and strongly inhibited proliferation of the HT-1080 (IC₅₀ values, 0.054—1.6 μM) and A549 (IC₅₀, 0.016—0.65 μM) cell lines. The characteristic morphological changes and ladder-like DNA fragmentation in those cells treated with the cardenolides indicated the antiproliferative activity was due to the induction of apoptosis.