Cytotoxic effect of root extract of Tiliacora racemosa and oil of Semecarpus anacardium nut in human tumour cells.

Tiliacora racemosa and Semecarpus anacardium, the two plants frequently used in Ayurvedic medicine for the treatment of cancerous diseases, have been selected to examine their action in four human tumour cell lines: acute myeloblastic leukaemia (HL-60), chronic myelogenic leukaemia (K-562), breast adenocarcinoma (MCF-7) and cervical epithelial carcinoma (HeLa). In cells grown in appropriate media the ethanol extract of T. racemosa root, the total alkaloids isolated from this organ and S. anacardium nut oil prepared according to the Ayurvedic principle were found to have cytotoxic activity. The alkaloid fraction from T. racemosa had maximum cytotoxicity and was effective against all four cell lines. S. anacardium oil was cytotoxic only in leukaemic cells. These herbal preparations were not cytotoxic towards normal human lymphocytes, suggesting their action is specific for tumour cells. On microscopic examination the cells treated with these agents exhibited characteristic morphological features of apoptosis, such as cell shrinkage, and the formation of apoptotic bodies. Fluorescent staining with propidium iodide revealed distinct chromatin condensation and nuclear fragmentation. The apoptotic index paralleled the cytotoxic parameters, and fragmented DNA extracted free of genomic DNA from treated cells displayed a typical ladder pattern on gel electrophoresis. Apoptosis induced by alkaloids and phenolics, the active principles present in T. racemosa and S. anacardium, respectively, was found to be mediated by the activation of caspases.