Antioxidant potentials of Iranian Carica papaya juice in vitro and in vivo are comparable to alpha-tocopherol.

Carica papaya is widely cultivated throughout the world and is used as a food and also as a traditional medicine, particularly as an antiseptic and contraceptive. The present study was designed to explore the toxicological and antioxidant potential of dried C. papaya juice in vitro and in vivo. The oral LD(50) of the juice of C. papaya was determined, and the antioxidant potentials determined by DPPH and FRAP tests. In vivo examination was performed after oral administration of dried papaya juice to rats for 2 weeks at doses of 100, 200 and 400 mg/kg. Blood TBARS and FRAP assays were used to determine the potential of the juice to act against oxidative stress. The acute toxicity test (LD(50)) demonstrated that papaya juice is not lethal up to a dose of 1500 mg/kg after oral administration and thus is considered nontoxic. In treated groups, no sign of toxicity was observed. In vitro evaluation of the antioxidant effects of papaya showed that the highest antioxidant activity (80%) was observed with a concentration of 17.6 mg/mL. Blood lipid peroxidation levels decreased significantly after administration of all doses of papaya juice (100, 200, 400 mg/kg/day) to 35.5%, 39.5% and 40.86% of the control, respectively, compared with a value of 28.8% for vitamin E. The blood total antioxidant power was increased significantly by all doses of papaya juice (100, 200, 400 mg/kg/day) to 11.11%, 23.58% and 23.14% of the control, respectively. The value for vitamin E was 18.44%. This preliminary study indicates the safety and antioxidative stress potential of the juice of C. papaya, which was found to be comparable to the standard antioxidant compound alpha-tocopherol.