Introduction

The World Health Organisation (WHO) estimates that 4 billion people, i.e. 80% of the world population, use herbal medicine for some aspect of primary health care (Farnsworth et al., 1985). Many herbs either wholly or their extracts are consumed by pregnant women effects of which are not known on the mother and the children. Ocimum gratissimum (Linn) is one of the herbs commonly consume by pregnant women in Nigeria. O. gratissimum of the family Labiaceae is native to the tropical and warm temperate region of the old world. O.gratissimum is one of the species from the genus. It is commonly called African basil or shrubby basil. It is Efinrin in Yoruba, Aai doya ta gida in Hausa and Nchonwu in Igbo (Owulade, 2004). In Nigeria, the plant is used in the treatment of miscarriage (Ogbe et al., 2009), diarrhoea (Sofowora, 1993), and high fever (Oliver, 1960). It has also been reported to have antibacterial (Nakamura et al., 1999) and antihelmintic (Pessoa et al., 2002) activities. This is however, without information on its effect on progesterone and fetal outcome during pregnancy. This study was therefore designed to provide information on the effect of aqueous extract of O. gratissimum leaves on progesterone and fetal outcome during pregnancy. Several studies have shown that plant extracts could alter the concentrations and functions of female reproductive hormones (Telefo et al., 1998 and Benie et al., 2003).

Materials And Methods

Preparation of Extract

Treatment of Rats

External Examination of the Foetuses

Progesterone Assay

Statistical Analysis

Results

Effects of aqueous extract of O. gratissimum on litter size, litter weight, maternal weight gain and serum progesterone in rats were shown in Table 1.

O. gratissimum caused increased litter size from 6.7±1.6 in the control group to 9.2±0.7 (p<0.01) and 9.4±1.2 (p<0.003) in 100mg/kg and 200mg/kg O. gratissimum treated group respectively. There was no statistical significant difference in the litter size among the treated groups.

There was reduction in litter weight from 6.7±0.7g in the control group to 4.5±0.1g (p<0.0002) and 4.3±0.2g (p<0.0003) in the 100mg/kg and 200mg/kg treated groups respectively. There was no statistically significant difference in the litter weight among the treated groups.

Aqueous extract of O. gratissimum caused reduced maternal weight gain in the treated group compared to the control. Maternal weight gain reduced from 63.7±2.6g in the control to 56.0±1.4g (p<0.05) and 56.3±31.6g (p<0.05) in the 100mg/kg and 200mg/kg treated groups respectively. There was no statistically significant difference in the litter weight among the treated groups.

There was statistically significant increase in serum progesterone in O. gratissimum treated group compared to the control group. Serum progesterone increased from 101.4±4.8ng/ml in the control group to 109.3±2.7ng /ml (p<0.003) and 111.7±1.6ng/ml (p<0.002) in the 100mg/kg and 200mg/kg treated groups respectively.

Figure 1

Table 1. Effects of aqueous extract of on litter size, litter weight, maternal weight gain and serum progesterone in rats.

Discussion

The results of our study indicate that aqueous extract of O. gratissimum increased litter size and serum progesterone in rats and reduced litter weight and maternal weight gain during pregnancy.

Some of the constituents of O. gratissimum are alkaloids, saponins, tannins, phlobatannins, anthraquinones, steroids, terpenoids, flavonoids, and cardiac glycosides (Akinmoladun et al., 2007 and Edeoga et al., 2006). Studies by Yu et al., (2003) showed that saponin treatments lower serum androgens and 17β-estradiol, but elevate progesterone levels, suggesting that saponins modulates steriodogenesis in the ovary. The observed increase in plasma progesterone concentration could be due to stimulatory effects of O. grattisimum on progesterone production. But because of the anti- diarrhoeal effects of O. grattisimum (Sofowora, 1993), it could have other mechanisms of action.

Progesterone has an antiestrogenic effect on the myometrial cell, decreasing their excitability, their sensitivity to oxytocin, and their spontaneous electrical activity while increasing their membrane potential (Ganong, 2003). The increased litter size could be due to the ability of progesterone to reduce myometrial cells excitability, thereby increasing the number of implantation and subsequent number of life fetuses. The reduced litter weight could be due to increased number of fetuses, but because of the accompanied reduction in maternal weight there might be associated antinutrient agents in the O. grattisimum extract.

There is need for further study in order to isolate the active compound that is responsible for the increased progesterone and those that are responsible for the reduced maternal weight and fetal weight. In conclusion, oral administration of aqueous leaf extract of O. gratissimum could be effective in increasing implantation and prevent premature delivery.