Abstract

Effect of Hibiscus sabdariffa L. (family Malvecea) calyx anthocyanin was investigated on circulating levels of reproductive hormones in rabbits (Oryctolagus cuniculus). Forty (40) rabbits (twenty each for male and female) weighing 1.2 ± 0.2 kg were grouped into two control (water control, anthocyanin (delphinidin-3-monoglucoside) standard) and two experimental groups (whole extract (calyces ofH. sabdariffa L.) and anthocyanin extract of calyces of H. sabdariffa L). While the water control group received 1.0 ml of water at 0900 h everyday for 28 days at 14:10 light/dark regime, the anthocyanin control and experimental group were administered 200 mg/kg oral doses of the different preparations. Blood samples were drawn prior to administration (day zero) and every seven days at 0900 h for the estimation of serum prolactin, follicle stimulating hormone and testosterone using ELISA. 28-day daily oral administration of delphinidin-3-monoglucoside and anthocyanin-rich extract of H. sabdariffa L. to rabbits is associated with high circulating prolactin in males and non-lactating female rabbits. This may be potentially important in phytotherapuetic induction of milk production in lactating animals. This treatment regime is also associated with lowered circulating FSH in males and female rabbits. Long-term reduction in circulating FSH levels might play important role in failed follicular development in developing female animals and gonadal atrophy in matured animals.

Key words: Hibiscus sabdariffa, anthocyanins, serum prolactin, follicle stimulating hormone, testosterone.