Effect of Carica papaya bark extract on oxidative stress parameters in testes of male albino rats

Summary: Carica papaya bark has contraceptive benefits when given at a high dose in male rats the mechanism at which it achieves this is yet to be fully understood. Forty male Wistar rats were used for the study. They were randomized into 8 groups Ia, IIa, IIIa, Ib, IIb, IIIb, IV and V respectively (n=5). Groups Ia-IIIa and Ib-IIIb were treated for 4 and 8 weeks with Carica papaya bark extract at doses 50 and 100 mg ml -1 day -1 comparing to 2-5 ml distilled water baseline control. Group IV rats were observed for reversibility treated with alternating bark extract and distilled water for 16 weeks (8 weeks each). They were compared to Group V treated with distilled water alone for similar duration. The rats were sacrificed under chloroform anesthesia. The estimated parameters were testes volumes biochemical activities of testicular antioxidant enzymes and non-enzymes [superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH) and malondialdehyde (MDA)] as well as total protein (TP). The extract treated groups (Groups Ia, IIa, Ib & IIb) showed a decrease in TP and testicular volume. Also in these groups were significant increases in testicular MDA levels compared to control (Groups IIIa & IIIb). At both durations for the two doses, the extract resulted in a significant decrease in antioxidant enzymes. Animals in the reversibility study group showed values similar to baseline control. In conclusion, Carica papaya leaf extract essentially perturbed the testicular oxidative system this may be responsible for the contraceptive effect seen. Industrial relevance: T he contraceptive benefits of aqueous extract of Carica papaya bark in orally treated male rats had been confirmed. This present study was tailored at reviewing variations in the gonadal proteins and stressors index in male rats administered established contraceptive doses of the extract. This would be helpful to industries intending to develop this herbal preparation as a contraceptive adjunct because it provides base line biochemical information on the testes that explains the likely possible mechanism of action of the herb.