Bioavailability and antioxidant protection of lycopene from watermelon

Watermelons are a rich source of the carotenoid lycopene. Researchers have reported that lycopene acts as an antioxidant in vitro by providing protection to human cells against oxygen and peroxy radicals. The objectives of this study were to evaluate the antioxidant protection provided to subjects by 20 or 40 mg/day of lycopene from watermelon. Twelve healthy, non-smoking adults (six men and six women) were given three treatments of a control, 20 and 40 mg/day of lycopene from watermelon juice for three weeks in a nineteen-week crossover study. Each treatment period was followed by a four-week lycopene depletion washout period. Plasma was analyzed for malondialdehyde formation products (MDA), plasma glutathione peroxidase (GPX) and ferric reducing ability of plasma (FRAP). Lycopene was readily absorbed by the subjects from the non-heat processed watermelon juice, but there was not a linear dose response. There were no significant differences in MDA, GPX or FRAP levels with either dosage level of lycopene or between treatments and controls. There were gender differences in MDA levels with women having higher MDA levels compared to men. However, the inclusion of lycopene to the diet in the form of watermelon juice did not affect the antioxidant status of healthy subjects.