Allanblackia floribunda Oliv.: An aphrodisiac plant with vasorelaxant properties

Ethnopharmacological relevance: Allanblackia floribunda Oliv. is one of the most commonly used medicinal plant in Cameroon. The stem bark of the plant is traditionally used for its aphrodisiac and antihypertensive properties. Aim of the study: To validate the traditional uses of Allanblackia floribunda stem bark ethanol extract through the evaluation of their aphrodisiac and vasorelaxant properties. Materials and methods: The extract's ability to increase sexual desire and the frequencies of erection (mount), intromission and prolonged latency of ejaculation were studied on adult male rats. The vasodilator effect was investigated using isolated rat aorta rings. Tests were conducted using fractions obtained by reverse phase column-chromatography (CC), after the acquisition of the HPLC fingerprint of the ethanol extract, resulted the most active in previous studies. Results: The CC allowed the isolation of five fractions whose aphrodisiac and vasodilator activities were tested and compared with those of the whole extract. Four compounds were identified and characterized, three of them, Fukugiside, Morelloflavone and Volkensiflavone, are secondary metabolites known to be in Allanblackia floribunda; the fourth, Spicataside, is a biflavonoid glycoside known to be present in the genus Garcinia but never found neither in Allanblackia floribunda nor in Allanblackia genus. The crude ethanolic extract (CEE) induced a relaxation on aorta rings with EC50=11±2 μg/mL and Morelloflavone displayed a similar activity with EC50=42±6 μg/mL; for all the other compounds only the vasodilation % at the maximum concentration assessable (90 μg/mL) was determined: 30±8 (Fukugiside), 24±6 (Spicataside), 33±4 (Morelloflavone+Volkensiflavone), 47±1 (Volkensiflavone). Regarding the activity on male sexual behaviour, only CEE and Fukugiside showed activity in the 9 parameters evaluated. Conclusions: These results may support the traditional uses of Allanblackia floribunda as aphrodisiac plant with antihypertensive properties suggesting the phytocomplex as responsible for the claimed activity.