Administration Dependent Antioxidant Effect of Carica papaya Seeds Water Extract

Carica papaya is widely used in folk medicine as herbal remedy to prevent, protect against, and cure several diseases. These curative properties are based on the presence in different parts of the plant of phytochemical nutrients with antioxidant effect. Seeds are the less exploited part; thus this study is aimed at assessing the antioxidant activities of the C. papaya seeds water extract against hydrogen peroxide (H2O2) oxidative stress in human skin Detroit 550 fibroblasts. C. papaya seeds water extract is not toxic and acts as a potent free radical scavenger, providing protection to Detroit 550 fibroblasts that underwent H2O2 oxidative stress. Data show that (i) the maximum protective effect is achieved by the simultaneous administration of the extract with 1 mM H2O2; (ii) the extract in presence of an oxidative stress does not increase catalase activity and prevents the release of cytochrome C and the inner mitochondrial transmembrane potential (Δψ m ) loss; (iii) the extract is more efficient than vitamin C to hamper the oxidative damage; (iv) the purified subfractions of the seeds water extract exert the same antioxidant effect of whole extract. In conclusion, C. papaya seeds water extract is potentially useful for protection against oxidative stress.