Modulatory effect of Inula racemosa Hook. f. (Asteraceae) on experimental atherosclerosis in guinea-pigs

Abstract

Inula racemosa Hook. f. is indicated for precordial chest pain in Ayurveda. In this study, the effects of a hexane (IrH) and an alcohol extract (IrA) of Inula racemosa on atherosclerosis induced by a high-fat diet in guinea-pigs were investigated. After 30 days on a high-fat diet (guinea-pig pellet diet + 0.2% w/w cholesterol) six animals were killed and evaluated for the onset of early atherosclerotic changes in coronary artery, aorta and major organs. The remaining animals were assigned to 5 groups of six animals each and fed for the following 90 days with a pellet diet + 0.15% w/w cholesterol (positive control) along with 100 mg/kg IrA, 100 mg/kg IrH or 10 mg/kg atorvastatin calcium. The normal control group received only the pellet diet. At the end of experimental period, serum lipid levels, heart and liver antioxidant status, area of lipophilic aortic lesions and histopathology of coronary artery were estimated. IrA decreased total cholesterol, triglycerides, low-density lipoprotein cholesterol and the atherogenic index, and increased high-density lipoprotein cholesterol compared with the positive control. It scavenged thiobarbituric acid reactive substances and increased reduced glutathione in liver, and enhanced superoxide dismutase and glutathione peroxidase in heart. Aortic lesion area and % bodyweight increase was least in the IrA-treated group. Coronary artery changes due to the high-fat diet were reversed by the extracts. The observed effects are presumably mediated by phenolics in IrA and sesquiterpene lactones in IrH. The results demonstrate the anti-atherogenic effect of I. racemosa, thus validating the cardioprotective and anti-obesity claims in traditional medicine.