Cardiovascular receptors binding affinity of aqueous extracts from Allium species.

The aims of this study were to evaluate whether the antihypertensive effect of garlic could to be associated to interactions with adrenergic and dopaminergic receptors involved in regulating blood pressure and to compare these data with those obtained from wild Allium species. Methods The aqueous extracts of bulbs or leaves of Allium sativum L. (garlic), Allium neapolitanum Cyr., Allium subhirsutum L., and Allium roseum L. were tested for their in vitro affinity for the adrenergic (a1, a2, b1 and b2) and dopaminergic (D1 and D2) receptors by radioligand binding assays. Results Interesting results were shown by bulbs extracts of A. neapolitanum and A. subhirsutum with higher affinities for the b2 receptors and by bulbs extract of A. roseum for D2 receptors. Conclusions The known antihypertensive activity of Allium sativum cannot be correlated with binding to receptors involved in blood pressure regulation. However, aqueous extracts of the wild-type species of Allium show much higher affinities, warranting further explorations.