A mint purified extract protects human keratinocytes from short-term, chemically induced oxidative stress

Oxidative stress is strictly correlated to the pathogenesis of many diseases, and a diet rich in fruits and vegetables, or adequately integrated, is currently considered to be a protective and preventive factor. This study aimed to analyze the efficacy of a 1 h preincubation with the highest nontoxic dose of a characterized Mentha longifolia extract (80 μg/mL) in protecting human keratinocytes (NCTC2544) from chemically induced oxidative stress (500 μM H2O2 for 2, 16, and 24 h). As reference synthetic pure compounds rosmarinic acid (360.31 μg/mL), a major mint phenolic constituent, and resveratrol (31.95 mg/mL), a well-known antioxidant, were used. Cellular viability was significantly protected by mint, which limited protein and DNA damage, decreased lipid peroxidation, and preserved glutathione and superoxide dismutase activity in the shorter phases of oxidative stress induction, in extents comparable to or better than those of pure compounds. These data suggest that mint use as only a flavoring has to be revised, taking into consideration its enrichment in foodstuff and cosmetics.