Background: Ethanol with inducing oxidative stress causes tissue damages. Old studies showed that plant extracts could have protective effect against these damages. Phenolic acids, particularly flavonoids, are a large group of organic compounds in plants that showed important biological activities such as antioxidant properties. The aim of this study was to investigate antioxidant and protective activities of extract of G. glabra against ethanol induced testicular damages. Methods: Twenty male Wistar albino rats were divided into three groups as follows: Group 1 (control group: received only saline), Group 2 (ethanol group: was treated with only ethanol) and Group 3 (ethanol + G. glabra). Experimental period in all groups were two weeks. Water, ethanol and G. glabra extract was administered daily by gavage. At the end of experiments, all the animals were killed and testes were removed for histological and biochemical analyses. Result: Results indicated that G. glabra extract had high total phenolic (6.84 ± 1.03 mg GAE/g of dryextract) and flavonoid (1.64 ± 0.37 mg QE/g of dry extract) contents. The extracts studied possess strong antioxidant activity (IC50= 0.112 ± 0.006 mg/ml) and are more active than ascorbic acid (IC50; 0.142 ± 0.002 mg/ml) as control. Also, ethanol administration caused increase in H2O2 and malon dealdehyde (MDA) level and then following decrease in body and reproductive organ weights, sperm counts and also total protein and SOD enzyme activity compared to control group. However, administration of ethanol together with G. glabra resulted in significant improvements in body and organ weights, sperm counts, SOD activity and MDA level compared to ethanol group. Conclusion: The results of this study suggest that G. glabra extract has protective effect against ethanol induced testicular damages.
