ABSTRACTThe study aimed to evaluate the effect of Echinacea extract (E) on the testicular antioxidant function in normal rats or subjected to the antiandrogen compound, cyproterone acetate (CA ). The rats were divided into 5 groups treated daily via oral tube for two intervals 2 and 4 weeks, 1st control, 2nd E (63 mg/kg), 3rd CA (25 mg/kg), 4th E+CA and 5° E as prophylaxis one week before treatment with E+CA. Then CA was used as a positive control compound with antiandrogenic activity with the proposed testicular oxidant. Weights of the body, testes, epididymis, and vas deferens were recorded. Sperm count, nitric oxide (NO), calcium ion (Ca2+) and malondialdehyde (MDA) contents, as well as superoxide dismutase (SOD) and 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. The activities of SOD and GST significantly decreased in addition to the significant increase in NO, MDA content reflecting the oxidative state of the testes in CA-treated rats. The prophylactic effect of E treatment, in a time-related manner, showed a significant improvement in the antioxidant status of testicular tissue which is more pronounced than E+CA treatment. Key departments: echinacea, cyproterone acetate, reproductive system, antioxidantsINTRODUCTIONThe antioxidant system plays an effective role in protecting the testicles and other biological tissues below a critical threshold of reactive oxygen species (ROS), thus preventing testicular dysfunction (Oschsendorf, 1999). ROS-mediated oxidative stress is one of the crucial reasons for infertility and reduced sperm viability, and the increased level of free radicals can cause degeneration... middle of paper... at local levels such as in the testis, when nuclear the receptors are (too) saturated. Androgens can also induce rapid calcium fluxes in a variety of 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 the decrease in Ca ion content in the testicles. The study suggests that Echinacea supplementation, especially one week before cyproterone acetate, shows an improvement in oxidative stress induced by cyproterone acetate treatment. This may be due to the antioxidant activity of Echinacea. The antiandrogenic effect of E may, in addition to anti-inflammatory and immune-boosting activity, add value for use as a co-treatment for male contraceptives or in the treatment of prostate cancer which needs further investigation.