The toxicity of Callilepis laureola, a South African traditional herbal medicine

Objectives: To review the literature on the toxicity of Callilepis laureola , and to assess the cytotoxicity of C laureola in human hepatoblastoma Hep G2 cells in vitro. Design and methods: Cells were incubated for up to 48 h in the presence of increasing concentrations of an aqueous extract of C. laureola (0.3-13.3 mg /mL). Cytotoxicity was quantitated spectrophotometrically by the metabolism of the tetrazolium. dye NM. Cytoviability of the control cells was conside red to be 100%. Results: C. laureola produced cytotoxicity in a concentration-dependent man ner. Cytotoxicity was significant at all concentrations tested (0.3-2.5 mg/ mL, p < 0.05 vs. controls and 3.3-13.3 mg/mL, p < 0.0001 vs. controls). Aft er 6 h, 100% toxicity was observed at a concentration of 6.7 mg/mL. Conclusion: C. laurcola causes significant cytotoxicity in Hep G2 cells in vitro. These findings are in accordance with the observed hepatotoxicity in clinical cases of C. laureola poisoning. (C) 2001 The Canadian Society of Clinical Chemists. All rights reserved.