A proposed screening strategy for evaluating the genotoxicity potential of botanicals and botanical extracts.

Botanicals have long been used to promote health and treat diseases, but the safety of many currently marketed botanicals has not been adequately evaluated. Given the chemical complexity of botanicals, which often contain numerous unknown constituents, and their widespread use, comprehensive toxicity assessments are needed. The Botanical Safety Consortium was established to address this challenge. This international group of experts in toxicology, chemistry, bioinformatics, and pharmacognosy is developing a toolkit of assays to generate reliable toxicological profiles for botanicals. Genotoxicity assessment is especially critical, because, unlike other toxicities, genotoxicity is not adequately identified by adverse event and history-of-use reports, and genotoxicity is directly linked to health consequences such as cancer and birth defects. The Consortium's Genotoxicity Technical Working Group is exploring a genotoxicity testing strategy based on the use of in silico modeling and the bacterial reverse mutation and in vitro micronucleus assays and including several options for additional tests to further characterize genotoxicity and mode of action when indicated. The effectiveness of this testing strategy is being evaluated using 13 well-characterized botanicals with existing toxicological data as case studies. A brief overview of each of these 13 botanicals is provided. The final strategy for developing comprehensive genotoxicity profiles of botanicals will incorporate published genotoxicity data, chemical composition information, in silico and in vitro test data, and human exposure data, reducing the need for animal testing.