Effects of aqueous extracts of medicinal plants on MNNG-treated rat hepatocytes in primary cultures

Aqueous extracts of Nigella sativa (Ranunculaceae) (Ns), Teucrium polium (Labiatae) (Tp) and Trigonella foenum-graecum (Fabaceae) (Tf) have been traditionally used to treat inflammations, liver disorders, and arthritis. Experimentally, it has been demonstrated that these herbs possess antioxidant, anti-inflammatory and hepatoprotective properties. To evaluate their in vitro toxicological properties and potential antimutagenic effects aqueous extracts of the three plants were tested in primary rat hepatocyte cultures against N-methyl-N'-nitro-N-nitrosoguanidine. The extracts were applied before, during and after application of MNNG to discriminate between different mechanisms of action. Tp itself significantly increased apoptosis, but in the combined treatment with MNNG significantly reduced it. Post-treatment with Ns or combined treatment with Tf significantly reduced the percentages of necrotic cells. The three plant extracts themselves significantly increased the frequency of chromosomal aberrations. Summarizing, our results suggest that aqueous extracts of the three herbs have neither cytoprotective nor antimutagenic activity, instead there is evidence for a mutagenic potential.