Antihyperlipidemic and Antioxidant Effects of Phaseolus Vulgaris Linn in Wistar Rats

Abstract

In this study, the antihyperlipidemic and antioxidants activities of the extract and fractions of Phaseolus vulgaris L. were evaluated. The crude extract (PVE) of dried pulverized plant material was obtained by maceration in methylene chloride/methanol (1:1) while the solvent fractions were obtained by successive solvent-solvent partition in separating funnel between the crude extract suspended in aqueous medium and solvents of increasing polarity to obtain the n-hexane fraction (PVHF), ethylacetate fraction (PVEF), and butanol fraction (PVBF) in that order.Antihyperlipidemic effects of the extracts and fractions were investigated using acute, sub-acute and chronic models. In all threemodels, treatment with (PVE) caused significantreduction (P<0.05) in the lipid profile parameters with the most significance seen in the sub acute study where total cholesterol was decreased by 38.44%. Triglycerides level was significantly decreased (P<0.05) by 18.18% in the acute study model.Similarly, very low density lipoprotein (VLDL-C)and low density lipoprotein (LDL-C) wasrespectively decreased by 18.18% and 48.73% in the acute antihyperlipidemia model. In contrast, high density lipoprotein (HDL-C) level was significantly (P<0.05) increased in the acute phase by 20.85%.In all study protocols involving the various fraction there were significant increase(P<0.05) in lipid profile. PVEF (400 mg/kg) produced- the most significant reduction in total cholesterol level in the acute study with percentage decrease of 22.10% compared to the control treatment. Triglycerides level was similarly reduced by 21.59% and 15.91% at PVHF (200 mg/kg) and PVEF (200 mg/kg) with the acute study.The sub-acute protocol showed significant decrease at PVBF 200 mg/kg percentage decrease of 17.28%. VLDL-C level for the fraction study showed significant decrease (P<0.05) at PVHF 200 mg/kg and PVEF 200 mg/kg with percentage decrease of 21.59% and 15.91% during the acute protocol, the sub-acute protocol showed significant decrease at PVBF 200 mg/kg percentage decrease of 17.28. LDL-C level for fraction extract study showed dose dependent significance decrease (P<0.05) seen at PVHF 100 mg/kg, PVEF100 mg/kg, and 200 mg/kg with percentage decrease of 47.19%, 41.62% and 53.39% respectively during the acute protocol, Finally in the chronic protocol a significant decrease was seen with PVHF 200mg/kg, PVEF 100 mg/kg, and PVBF 200 mg/kg with percentage decrease of 26.03%, 24.82% and 20.05% respectively. HDL-C level for extract study showed dose dependent significant increase (P<0.05) seen at PVHF 100 mg/kg, PVEF 100 mg/kg and 200 mg/kg with percentage increase of 30.44%, 28.88% and 30.86%. DPPH reduction and nitric oxide scavenging assays were used in the investigation of the extract and fractions for the in vitro antioxidant activities study, the antioxidant activities of the extract and fractions were further determined in vivo in rats. Antioxidant enzymes and factors such as catalase, glutathione peroxidase, and lipid peroxidation activities were measured in carbon tetrachloride-treated rats treated with or without the extract and fractions studies. The highest percentage reduction of DPPH was 80.61% seen with PVEF and PVBF fraction at 400 mg/kg. The highest percentage reduction of nitric oxide was 75.86% seen with PVHF at 200 mg/kg. The in vitro study showed significant increased (P<0.05) scavenging activity with the PVHF and PVEF having scavenging activity comparable with ascorbic acid. In in-vivo antioxidant assay showed that the Lipid peroxidation levels estimated by thiobarbituric acid reaction showed no significant (P>0.05) increase or decrease in the serum MDA of both the treated and untreated group, while in catalase activity estimation showed significant (P<0.05) increase was seen with PVE 100 mg/kg of 71.05%, Glutathione peroxidise activity showed the most significant percentage (P<0.05) increase of 76.19% for PVBF 100 mg/kg.The results of the study showed that the extracts and fractions of Phaseolus vulgaris posses anti-hyperlipidemic and antioxidant with the PVEF showing better and more consistent effects with all protocols used in the investigation.