Mutagenic and antimutagenic properties of extracts from South African traditional medicinal plants

Aim of the study: The aim of this paper was to summarize the results of our investigations on the in vitro genotoxic as well as antigenotoxic effects of a great number of selected South African traditional medicinal plants. Materials and methods: Investigations of methanol and dichloromethane extracts of selected plants were conducted with the bacterial Ames, Umu-C and VITOTOX (R) tests, and with the cytochalasin B micronucleus test and alkaline comet assay in human white blood cells. Results: A number of extracts were found to have genotoxic properties. Amongst the genotoxic plant extracts, especially methanol extracts of Helichrysum simillimum DC. (Asteraceae) should be highlighted. On the other hand, some plant extracts also showed antimutagenic potential. Here Bauhinia galpinii N.E.Br. (Fabaceae) and especially Chlerodendrum myricoides (Hochst.) Vatke (=Rotheca myricoides (Hochst.) Steane & Mabb.; Lamiaceae) appear to have antimutagenic properties. Conclusion: The safe use of Helichrysum similimum should be questioned and further investigations on its mutagenicity and overall biological properties should be encouraged. Antimutagenic properties of especially Bauhinia galpinii and Rotheca myricoides are considered of particular interest as it may be assumed that these antimutagenic natural substances are able to lower the cancer risk from everyday exposures to environmental mutagens as well as to mutagenic pharmaceuticals. (C) 2008 Elsevier Ireland Ltd. All rights reserved.