Antihypertensive and Hypolipidemic Effect of Ethyl-acetate Fraction of Adenium obesum (Forssk.) Roem. & Schult. Stem Bark Extract on L-NAME Induced Hypertension in Rats

Abstract

Introduction: Hypertension is a major health problem worldwide due to its high prevalence and its association with an increased risk of cardiovascular disease. However, the folkloric claim regarding the potential of Adenium obesum extracts and column fractions in the management of hypertension lacks scientific substantiation or refutation. Aim: The present study aimed to investigate the hypolipidemic, and antihypertensive properties of A. obesum stem bark extracts and fractions at dosages of 100, 200, and 300 mg/kg body weight in rats. Methods: Secondary metabolites were screened using standard methods, antihypertensive activity was assessed using tail cuff method for systolic and diastolic blood pressure also Cardio check was used to quantify for TC, HDL, LDL and VLDL of hypertensive rats.  Additionally, the extract was assayed for DPPH radical scavenging activities and characterized for Phenolics and Flavonoids using HPLC.  Results: Qualitative phytochemical analysis revealed the presence of alkaloids, cardiac glycosides, flavonoids, phenols, gums and resins, saponins, steroids, tannins, phytosterols, terpenoids, and triterpenoids. The quantitative phytochemical analysis demonstrated that the ethylacetate extract had the highest flavonoid content (108 ± 2.5 mg of QE/g), followed by the aqueous and powdered extracts (107 ± 0.50 mg of QE/g and 103 ± 1.60 mg of QE/g, respectively). The LD50 of the ethanol extract was found to be >5000 mg/kg, indicating low toxicity. The DPPH radical scavenging assay revealed that the ethyl acetate fractions exhibited the highest antioxidant activity, with IC50 values of 94.6 ± 20.7 µg/ml. The study demonstrated significant reduction in systolic blood pressure in week 3 (116.37±13.6mmHg) and (120.77±5.47mmHg) when administered 200mg/kg and 300mg/kg of ethylacetate extract respectively and reduced diastolic blood pressure at week 3 (80.50±9.63mmHg) when administered 300mg/kg of ethylacetate extract. This study  also demonstrated that the administration of A. obesum stem bark extract at doses of 100, 200, and 300 mg/kg body weight significantly exhibited a significant reduction in total cholesterol, triglycerides, and low-density lipoprotein levels, along with a significant increase in high-density lipoprotein levels in ethylacetate fraction (1.91 ±0.04Mmol/L) at 300mg/kg compared to standard drug 15mg/kg (1.72 ± 0.09Mmol/L)  HPLC analysis revealed the presence of several compounds with potential antihypertensive activity, including gallic acid, protocatechuic acid, gallocatechin, epigallocatechin,  catechin, caffeic acid, valeric acid, p-coumaric acid, sinapic acid, quercetin, and many others. Conclusion: These findings suggest that A. obesum stem bark extract may be effective in reducing hypertension, hyperlipidemia and associated oxidative stress.