Abstract

The effects of extracts of Ruellia praetermissa (Acanthaceae) on ovulation, implantation, uterine weight and foetal development were studied in adult rats. Female rats weighing 180 to 220 g were divided into three experimental groups. Group 1 was administered 200 mg/kg body weight of the extract at 10, 14 and 18 h respectively on proestrous rats. Vaginal smears were taken daily to monitor the oestrous cycle and ovulation. Group 2 consisted of pregnant rats, which received the same dose of the extract on days 1 - 5, 7 - 9, 9 - 17 and 1 - 17 of gestation. Gestational parameters (number of corpora Lutea, implantation sites, resorption sites and dead foetuses) were monitored. In group 3, non-pregnant mature female rats were treated with the same dose of the extracts from 1 - 17. The uterine muscle weight was recorded on days 4, 9, 15, and 18. Ovulation was partially blocked resulting in reduced number of ova in the oviduct of the treated rats (3 ± 1, 5 ± 1 and 10 ± 3 treated at 10: 00, 14: 00 and 18: 00 h respectively) compared with control (12 ± 5: p < 0.05). There was 20% increase in implantation rate in rats which received treatment for the first five days of gestation (p < 0.05). There is an increase (0.05 ± 0.002 - 0.35 ± 0.001) of the uterine weight comparable to that produced by using 3 µM 17b-estradiol (0.03 ± 0.001 - 0.35 ± 0.005). The decrease in effects on ovulation and the increase in the uterine walls are possibly due to flavaonoids (luteolin, quercetin, and apigenin). Increase in Implantation and the uterine weight are due in part by plant sterols (β-sistosterol and stigmasterol) identified in the EtOAc extracts of this plant drug. These findings provide the pharmacological basis for the traditional use of this plant for prenatal care in the North West Region of Cameroon.

Key words: Ruellia praetermissa, ovulation, implantation, uterine endometrium, flavonoids, plant sterols.