Pharmacological evaluation of Euphorbia hirta, Fagonia indica and Capparis decidua in hypertension through in-vivo and in vitro-assays

Abstract Objective This study determines the efficacy and probable underlying mode of action to the folk usage of Euphorbia hirta, Fagonia indica and Capparis decidua in hypertension. Methods The aqueous-methanol extracts of E. hirta (EH.Cr), F. indica (FI.Cr) and C. decidua (CD.Cr) were tested for antihypertensive effects in rats using non-invasive and in-vasive blood pressure measuring apparatus. In-vitro assays were carried out using isolated rat aortae using PowerLab station. Results EH.Cr, FI.Cr and CD.Cr at 500 mg/kg (orally) caused a fall in the mean systolic blood pressure in arsenic-induced hypertensive and normotensive rats, similar to nifedipine. In rat aortae, EH.Cr, CD.Cr and FI.Cr reversed low (20 mM), high (80 mM) K+ and phenylephrine (P.E)-driven contractions, while F. indica partially inhibited high K+ contractions. In the presence of TEA, F. indica remained unable to relax low K+ contractions. EH.Cr and CD.Cr moved Ca++ concentrations response curves to the right, like nifedipine. All fractions of EH.Cr and CD.Cr except aqueous, pet-ether and chloroform fractions of FI.Cr displayed Ca++ antagonistic activity. FI.Cr, its ethyl acetate and aqueous fraction exhibited TEA-sensitive potassium channel activation. On baseline tension, test materials also produced phentolamine-sensitive vasospasm. Conclusion E. hirta, F. indica and C. decidua possess antihypertensive activity in arsenic-induced hypertensive rats possibly mediated via endothelium-dependent vasorelaxation. In normotensive rats, E. hirta and C. decidua showed antihypertensive activities through endothelium-dependent and Ca++ antagonistic pathways, while F. indica exhibited potassium channel activation and Ca++ antagonistic like effects in its vasorelaxation. Additional weaker vasospastic effects were derived through α-adrenergic like pathways.