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 MTT. Cytoviability of the control cells was considered to be 100%. Results: C. laureola produced cytotoxicity in a concentration-dependent manner. 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). After 6 h, 100% toxicity was observed at a concentration of 6.7 mg/mL. Conclusion: C. laureola 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.