Hypolipidemic, Hypoglycemic and Anti-oxidant Activities of Flower Extracts of Allamanda Violacea A. DC (Apocynaceae)

Purpose: To investigate the anti-dyslipidemic, anti-oxidant and anti-diabetic activities of the aqueous extract and solvent fractions of A. violacea flowers. Methods: The aqueous extract was fractionated into petroleum ether, ether, chloroform, chloroformmethanol (4:1) and chloroform-methanol (3:2) fractions. Lipid lowering activity was evaluated in two models, viz, triton WR-1339 induced hyperlipimea in rats as well as fructose-rich high fat diet. To assess anti-oxidant activity, in-vitro model of non-enzymic superoxide hydroxyl radicals and microsomal lipid peroxidation by non-enzymic inducer was adopted. Hypoglycemic activity was evaluated by sucrose-loaded rat model. Results: Amongst the fractions, ether and chloroform fractions caused marked decrease in the levels of total cholesterol (Tc), triglycerides (Tg), plasma lipids (Pl), and protein by 24, 23, 23 and 22 %, and 24, 22, 23 and 19 %, respectively. In rats fed with high fat diet (HFD), ether and chloroform fractions lowered Tc, Tg and, Pl by 26, 25 and 26 %, and 18, 19 and 20 %, respectively. Significant decrease in superoxide anions, hydroxyl radicals and microsomal lipid peroxidation by ether and chloroform fractions was also observed. Chloroform, chloroform-methanol (4:1) and chloroform-methanol (3:2) fractions showed antihyperglycaemic activity to the extent of 25.2, 21.6 and 23.2 %, respectively. Conclusion: The flowers of this plant, especially the ether and chloroform extracts, may be suitable as an anti-oxidant supplement for lipid management.