Oestrous cycle of Wistar rats altered by sterol and triterpenes rich fraction of Adansonia digitata (Linn) root bark - A scientific rationale for contraceptive use

Objective: To investigate the effect of different fractions from the aqueous methanolic root bark of Adansonia digitata (Linn) on the estrous cycle of female Wistar rats and to elucidate their phytochemical content. Methods: Crude aqueous methanol extract of Adansonia digitata (Linn) root bark was fractionated by column chromatography using various ratios of hexane, acetyl acetate, methanol and distilled water. Fractions with similar trails on a thin layer chromatography were pooled into four fractions. Each fraction was then screened for its phytochemical content. Forty mature Wistar female rats weighing (135±28) g with regular estrous cycles were given each fraction at two dose levels while a control group received distilled water of equal volume. Treatments were given per os for 15 days starting from the day of estrus. Vaginal smears were observed daily for the duration of each cycle, frequency of occurrence of each stage of the estrous cycle and number of cycles for 15 days before and during treatment. At the end of treatment, rats were humanely sacrificed. Ovaries and uteri were weighed and processed for histopathology. Results: Hexane acetyl acetate and acetyl acetate methanol fractions at 150 mg/kg body weight and 300 mg/kg body weight prolonged the occurrence of proestrus and diestrus and produced atretic cyst-like ovaries at 300 mg/kg body weight. Acetyl acetate methanol treated rats also had low relative ovarian weights when compared to the control. Conclusions: Sterols and triterpenes in hexane acetyl acetate and acetyl acetate methanol fractions of the root bark may be responsible for the disruption of estrous cycle in female Wistar rats and may have a contraceptive effect