Quinine inhibits ovulation and produces oxidative stress in the ovary of cyclic Sprague-Dawley rats.

Background: Quinine has been reported to possess anti-spermatogenic activities.

Objectives: This study was carried out to determine the effect of quinine on ovarian function in Sprague-Dawley rats.

Methods: Twenty rats with regular 4-days oestrous cycle divided into 4 groups (N=5) were used. Group I received quinine at 30 mg/kg body weight by gavage for 28 days after which they were sacrificed. The ovaries were excised for biochemical oxidation of glutathione peroxidase (GSH), superoxide dismutase (SOD), catalase and malondialdehyde (MDA). Group II received single dose quinine at 30 mg/kg body weight at 0900 hrs on day of proestrus. Blood was obtained at 1800 hrs for hormonal assay of FSH and LH. The animals were sacrificed the next morning on estrus: oviducts were examined for ova count. Groups III and IV served as controls.

Results: Quinine treated rats recorded zero number of ova compared to control. Serum concentration of LH reduced significantly in the quinine treated group compared to the control. Furthermore, quinine significantly decreased the oxidant status of GSH, SOD and catalase and significantly increased MDA levels in the ovary compared to the control group.

Conclusion: Quinine completely blocks ovulation, suppresses LH surge, and produces oxidative stress in the ovary.