An ascorbic acid-enriched tomato genotype to fight UVA-induced oxidative stress in normal human keratinocytes.

UVA radiations contribute up to 95% of the total UV exposure and are known to induce cell damage, leading to apoptosis. Since the benefic effects of ascorbic acid on human health are well known, a new tomato genotype (named DHO4), highly rich in ascorbic acid, has been recently obtained. Here, we compared the effects of ascorbic acid and hydrophilic DHO4 extracts in protecting human keratinocytes exposed to UVA stress. Keratinocytes were pre-incubated with ascorbic acid or with extracts from the ascorbic acid enriched tomato genotype and irradiated with UVA light. Then, ROS production, intracellular GSH and lipid peroxidation levels were quantified. Western blots were carried out to evaluate mitogen-activated protein kinases cascade, activation of caspase-3 and inflammation levels. We demonstrated that ROS, GSH and lipid peroxidation levels were not altered in cell exposed to UVA stress when cells were pre-treated with ascorbic acid or with tomato extracts. In addition, no evidence of apoptosis and inflammation were observed in irradiated pre-treated cells. Altogether, we demonstrated the ability of an ascorbic acid enriched tomato genotype to counteract UVA-oxidative stress on human keratinocytes. This protective effect is due to the high concentration of vitamin C that acts as free radical scavenger. This novel tomato genotype may be used as genetic material in breeding schemes to produce improved varieties with higher antioxidant levels.