Bioactivity-guided isolation of cytotoxic constituents from three medicinal plants.

CONTEXT The ethanol extracts and their fractions of three Indian medicinal plants, Ervatamia coronaria (Jacq.) Stapf, (Apocynaceae), Mimosa pudica L. (Mimosaceae) and Caesalpinia bonduc (L.) Roxb. (Caesalpiniaceae) were tested for their cytotoxic activity in the brine shrimp lethality (BSL) bioassay and in various cancer cell lines. The plants were selected based on their traditional use in the treatment of cancer/tumors. OBJECTIVES To investigate the in vitro cytotoxicity of Ervatamia coronaria, Mimosa pudica and Caesalpinia bonduc. MATERIALS AND METHODS Ethanolic extracts and their fractions of E. coronaria, M. pudica and C. bonduc were subjected to cytotoxicity studies using BSL bioassay method with concentrations of 10, 50, 100, 500 and 1000 µg/ml. The alkaloid fraction of E. coronaria with significant cytotoxicity in BSL bioassay was subjected to in vitro cytotoxicity studies with HT-29, A-549, HepG-2, MCF-7 and L-6 cell lines at concentrations of 12.5, 25, 50, 100 and 200 µg/ml and a DNA fragmentation study using the HT-29 cell line. RESULTS The alkaloid fractions of E. coronaria and M. pudica showed significant cytotoxicity with LC50 values of 65.83 and 85.10 µg/ml in the BSL bioassay, respectively. The purified alkaloid fraction of E. coronaria exhibited highest cytotoxicity in HT-29, A-549 and MCF-7 cell lines with IC50 values of 32.5, 47.5 and 72.5 µg/ml, respectively, and induced DNA fragmentation in the HT-29 cell line at a concentration of 65 µg/ml. CONCLUSION The alkaloid fraction of E. coronaria exhibited significant cytotoxicity. Alkaloids such as ervatamine, apparicine and coronaridine that were earlier reported may be responsible for this activity.