SUMMARYThe study aimed to evaluate the effect of echinacea extract (E) on testicular antioxidant function in normal or subjected rats to an anti-androgenic compound, cyproterone acetate (CA). . The rats were divided into 5 groups treated daily via an oral probe for two intervals of 2 and 4 weeks, 1st control, 2nd E (63 mg/kg), 3rd CA (25 mg/kg), 4th E+CA and 5th E as a prophylactic one week. before E+CA treatment. Thus, CA is used as a positive control compound having antiandrogenic activity with the proposed testicular oxidant. The weight of the body, testes, epididymis and vas deferens was recorded. Sperm count, nitric oxide (NO), calcium ion (Ca2+) and malondialdhyde (MDA) content, in addition to superoxide dismutase (SOD), glutathione S-transferase (GST) activities were determined in testicular tissues. CA showed a direct negative effect on reproductive organ weight and a significant reducing effect on sperm count and Ca2+ content. SOD and GST activities were significantly decreased in addition to a significant increase in NO and MDA contents reflecting the oxidative state of the testes in CA-treated rats. The prophylactic effect of treatment E, as a function of time, showed a significant improvement in the antioxidant status of testicular tissue. which is more pronounced than the E+CA treatment. Key Services: Echinacea, Cyproterone Acetate, Reproductive System, AntioxidantsINTRODUCTIONThe antioxidant system plays an effective role in protecting the testes and other biological tissues below a critical threshold of reactive oxygen species (ROS), thereby preventing dysfunction testicular (Oschsendorf, 1999). ROS-mediated oxidative stress is one of the crucial reasons for infertility and decreased sperm viability, and the increased level of free radicals can cause degeneration...... middle of the 'article...... and local levels such as in the testes, when the nucleus is nuclear. the receptors are (over)saturated. Androgens can also induce rapid calcium fluxes in various cell types, including human prostate cancer cells and rat sertoli cells (Steinsapir et al., 1991; Gorczynska and Handelsman, 1995; Gorczyńska-Fjälling, 2004 ). This suggestion explains the effect of CA treatment on decreasing testicular Ca ion content. The study suggests that echinacea supplementation, especially one week before cyproterone acetate, shows improvement in oxidative stress induced by cyproterone acetate treatment. This may be due to the antioxidant activity of echinacea. The anti-androgenic effect of E may, in addition to its anti-inflammatory and immune activity, be useful for its use as a co-treatment of male contraceptives or in the treatment of prostate cancer which requires further research...