In vivo bioactivity-guided isolation of antifertility fraction of Waltheria indica Linn. root in male Wistar rats

Abstract

Abstract Background Waltheria indica is a multipurpose medicinal plant with abundance of phytochemical compounds. Antifertility effect of Waltheria indica Linn. root and leaves have been reported. However, the fraction responsible for this antifertility effect needs to be isolated for possible male contraceptive purpose. Therefore, this research was designed to isolate the antifertility fraction of Waltheria indica Linn. root (WILR) in an in vivo model using male Wistar rats. Crude ethanol extract of WILR was sequentially dissolved in hexane, dichloromethane, and ethyl acetate. Rats (n = 5) were administered with 200, 500, or 1000 μg/kg of hexane, dichloromethane, and ethyl acetate soluble extracts of WILR, while control received distilled water, daily for 15 days to determine the soluble extract with most antifertility effect. Thereafter, fractions were separated from dichloromethane soluble WILR extract by column and thin-layer chromatography. Rats (7 groups, n = 5) were administered with each of the fractions (DF1 to DF7; at 1000 μg/kg) to determine the fraction with the highest antifertility. Rats were thereafter sacrificed, and sperm parameters, reproductive hormones, testicular cholesterol, and protein were determined according to standard procedure. Histology of the testis was also done. Data were analyzed using ANOVA at p ≤ 0.05. Results Dichloromethane soluble fraction (500 μg/kg) significantly decreased sperm concentration (137.00 ± 9.85 to 107.00 ± 13.08 × 106 cells/mL), levels of testosterone (2.90 ± 0.65 to 1.50 ± 0.37 ng/mL), and FSH (0.08 ± 0.08 to 0.99 ± 0.08 IU/L). The dichloromethane soluble fraction also caused the loss of testicular interstitium and spermatogenic cells. DF5 significantly reduced sperm motility (92.00 ± 2.74 to 76.00 ± 5.48%) and LH (2.86 ± 0.52 to 1.47 ± 0.18 IU/L). DF5 also significantly increased levels of prolactin (1.22 ± 0.10 to 1.88 ± 0.48 ng/mL), testicular total protein (7.36 ± 0.35 to 8.54 ± 1.06 g/dL), and testicular cholesterol (34.17 ± 3.65 to 55.76 ± 6.08 mg/mL). Conclusion The results indicate that the DF5 is the bioactive fraction of WILR responsible for its antifertility effect. The possible antifertility mechanisms are through the reduction in sperm parameters, reproductive hormones, and histological changes in the testis.