Antihypertensive Effect of a Standardized Aqueous Extract of Hibiscus Sabdariffa (Zobo)And Hyphaene Thebaica (Goriba) In Cats: In Vivo Approach to the Hypotensive Mechanism
Dalhatu, A*1.Yunusa, U1.Mijinyawa, M.S2. Bashir Garba Ahmad3,Dr Hasiya, TI3, Abdulmaleek, M.A1., Idris, A1. Sani, Dalhat4.K, Amina, S.R1, Binta, M.Y1
ABSTRACT
Ethnopharmacologically, Hibiscus sabdariffa (HS) and Hyphaene Thebaica have been used as a folk remedy for the treatment of hypertension. The effects of Hibiscus sabdariffa (HS) in lowering blood pressure in human and animal hypertension have been documented. Moreover, several in vitro and in vivo ethnobotanical studies demonstrated evidence that extracts from the calyxes have been used in folk medicine to treat high blood pressure. More so, the evaluation of the physiological effects and health benefits of the extracts in clinical studies is most challenging. Aim: The aim of this study is to investigate the hypotensive and cardiac effects of the standardized aqueous extract of Hibiscus sabdariffa and Hyphaene Thebaica and to examine the evidence of its effectiveness on blood pressure based on ethnomedicinal, safety and toxicity. Methods: The study used a Randomized Clinical Trials, with three normotensive cats divided into three experimental groups: Hibiscus sabdariffa, Hyphaene Thebaica, and control. Each group had one cat. The cats were exposed to different treatments of single dose of standardized aqueous extracts which was inoculated intravenously through the femoral vein of the cats (0.2ml/1mg each of Hibiscus sabdariffa & Hyphaene Thebaica, 0.2ml/10mgHibiscus sabdariffa & Hyphaene Thebaica, and 0.2ml/100mg Hibiscus sabdariffa & Hyphaene Thebaica, and placebo for the control) for three days. In each experimental group, various doses concentration were increased from 0.2ml/mg up to 0.8mls. The cats’ blood pressure reaction or dose response was measured using the recording microdynamometre. Results: Intravenous administration of the extracts resulted in a biphasic dose-related hypotensive effects across Hibiscus sabdariffa group at lower doses, while Hyphaene Thebaica extract resulted in a biphasic dose related increase of blood pressure at lower doses ,and hypotensive response was noted at higher concentration of 0.8ml/100 mg. Comparatively, blood pressure in Hibiscus sabdariffa treated cats showed exponential decrease in blood pressure as doses increase while Hyphaene Thebaica raised the blood pressure at lower doses and therefore demonstrated exponential decrease of blood pressure at higher doses. Conclusion: These results suggest that Hyphaene Thebaica exhibited its initial hypotensive effects at higher dose related while Hibiscus sabdariffa exhibited its hypotensive effects at lower doses. Moreover, no adverse effects were reported during the clinical trials. However, further in vivo, and in vitro studies are required to validate the clinical efficacy of Hyphaene Thebaica and Hibiscus sabdariffa in large-scale studies.
Keywords: Hibiscus sabdariffa; Hyphaene Thebaica, Clinical trials; Hypotension