Frontiers in Genetics (Aug 2015)
Investigations of plant-derived products with the in vitro comet assay
Abstract
Approximately 80% of the world’s population still uses medicinal plants for its primary health care. Based on their traditional use for long periods of time they are often assumed to be safe. However, research has shown that a lot of plants which are used as food ingredients or in traditional medicine may be harmful and have for example toxic, genotoxic or carcinogenic properties. For this reason it is important to screen medicinal plants for their mutagenic potency. Plants exhibiting clear mutagenic properties should be considered potentially unsafe and certainly require further testing before their continued use can be recommended. On the other hand there is a continuous search for new medical preparations against a great number of ailments, including cancer. This is because existing medication often has unwanted side effects or because of loss of efficiency in the long term. Plants with obvious antimutagenic potential can be considered interesting for therapeutic use and merit further in depth investigations of their pharmacological properties. For this reason (traditional medicinal) plants are screened worldwide for their genotoxic and antigenotoxic properties. Following bioassay guided fractionations and further investigations the ‘active’ antigenotoxic component can then be isolated and become a lead substance of a new medical preparation or functional food product. It is impossible to perform a wide range of tests for screening purposes and often only the Ames assay is performed, which is insufficient. Furthermore, this test is most probably not the best choice when plant extracts need to be tested, because they often contain high amounts of histidine and have antibacterial properties. We have participated in many screening programs of medicinal plants and used different genotoxicity tests (mainly Ames assay, Vitotox test, micronucleus test and comet assay). Or results revealed that a combination of the Vitotox test and comet assay provides sufficiently reliable data with respect to genotoxicity as well as antigenotoxicity. This holds true for the testing of (medicinal) plant extracts but also other plant derived products, for example those aimed at identifying novel TB chemotherapeutic drugs. The investigation of smoke and smoke compounds as enhancers of seed germination and smoke treated plants provides another example in which the comet assay proved to be valuable in the assessment of potential adverse health effects resulting from such treatment.
Keywords
