Quercetin impairs the reproductive potential of male mice

Oxidative stress is a leading cause of male infertility. To combat this, germ cells and spermatozoa are endowed with various enzymes, vitamins and proteins. Certain other components of food, including bioflavonoids, also provide protection against free radicals. This study analysed the effect of quercetin, a bioflavonoid, on male reproductive function in adult mice, after intraperitoneal treatment with varying concentrations of quercetin (2, 8 and 20 mg kg(-1) b.wt.) for 2 weeks. Quercetin increased the generation of reactive oxygen species and lipid peroxidation in the testis with concomitant decrease in sperm count and motility in a dose-dependent manner. Activities of antioxidant enzymes catalase, superoxide dismutase and levels of reduced glutathione were found to be decreased in a dose-dependent manner. Also, the levels of oxidised glutathione were increased leading to a shift in redox ratio. The testicular histomorphology was also altered dose dependently. Germ cell kinetic study revealed significant loss of various germ cell populations with increasing dose of quercetin. Interestingly, there was a reduction in germinal epithelium thickness concomitant with an increase in seminiferous tubule lumen diameter. In conclusion, the deleterious effects of quercetin on germ cells could be attributed to its pro-oxidant ability that might affect the Sertoli cell functions.