Mechanistic Insights into the Antimutagenic Action of Catechin, Epicatechin, and Caffeic Acid in Ames Assay

Phenolic compounds are widely recognized for their diverse biological activities, including antioxidant, antimicrobial, anti-inflammatory, and anticancer effects, contributing significantly to human health. Among these, catechin, epicatechin, and caffeic acid have gained attention for their potential roles in maintaining DNA integrity. This study investigated the mutagenic and antimutagenic effects of these compounds using the Ames test with Salmonella typhimurium strains TA98 and TA100, in the presence and absence of metabolic activation (S9 fraction). Preliminary assays confirmed no cytotoxicity up to 5000 µg/plate, and none of the tested compounds exhibited mutagenic activity (mutation ratio ≤ 2). Antimutagenic evaluation demonstrated that catechin and epicatechin provided strong protection against frameshift mutations in TA98 without S9, with inhibition rates of 49–73% and 53–68%, respectively. This effect was slightly reduced under metabolic activation. In TA100, both compounds showed moderate inhibition without S9 but significantly enhanced activity with S9, reaching up to 88% and 67% inhibition, respectively, indicating effectiveness against metabolically activated mutagens. In contrast, caffeic acid exhibited moderate and variable antimutagenic activity, strongly influenced by concentration, strain type, and metabolic conditions. The higher efficacy of catechin and epicatechin is attributed to their structural complexity, multiple hydroxyl groups, and ability to scavenge free radicals and stabilize reactive intermediates, whereas the simpler structure of caffeic acid limits its protective capacity. Overall, these findings highlight the importance of dietary polyphenols in preserving genomic stability and support their potential applications in nutraceutical and pharmaceutical fields.