Cytotoxic effects of a decoction of Nigella sativa , Hemidesmus indicus and Smilax glabra on human hepatoma HepG2 cells M. Ira Thabrew a , Ragai R. Mitry b , Mohammed A. Morsy b , Robin D. Hughes b, T a Faculty of Medicine, University of Kelaniya, Ragama, Sri Lanka b Institute of Liver Studies, Guy’s, King’s and St Thomas’ School of Medicine, King’s College London, Bessemer Road, London SE5 9PJ, United Kingdom Received 1 November 2004; accepted 11 January 2005 Abstract A decoction of Nigella sativa seeds, Hemidesmus indicus root and Smilax glabra rhizome is used by traditional medical practitioners in Sri Lanka to treat cancer and has been shown to prevent chemically induced carcinogenesis in rats. The cytotoxicity of the decoction and the individual plant extracts were tested on the human hepatoma HepG2 cell line. The effects of 24 h incubation with different concentrations (0–50 mg/ml) of the extracts on HepG2 cells were determined. Results from MTT and SRB assays, and [ 14 C]-leucine and [ 3 H]- thymidine uptake demonstrated that the decoction had a strong dose-dependent cytotoxic activity. The greatest inhibitory effects were observed on DNA synthesis with both the decoction (91 F S.E. 3.7% inhibition) and N. sativa plant extract (88 F 3.8%) even at low concentrations (5 mg/ml). The three individual plant extracts were cytotoxic in the order of potency N. sativa N H. indicus N S. glabra . Flow cytometric analysis using Annexin V and propidium iodide staining showed that after 24 h exposure to the decoction, cells were in the late stage of apoptosis and/or necrosis. Further experiments are worthwhile to determine the anticancer potential of this plant decoction and its components. D 2005 Elsevier Inc. All rights reserved. Keywords: Nigella sativa ; Hemidesmus indicus ; Smilax glabra; Cytotoxicity; HepG2 cells; Hepatoma 0024-3205/$ - see front matter D 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.lfs.2005.01.022 T Corresponding author. Tel.: +44 20 7346 3137; fax: +44 20 7346 3760. E-mail address: robin.hughes@kcl.ac.uk (R.D. Hughes). Life Sciences 77 (2005) 1319 – 1330 www.elsevier.com/locate/lifescie