Hypoglycemic, hypolipidaemic and cytoprotective effects of lotus seeds (Nelumbo nucifera) in sprague-dawley rats

Abstract

A study was undertaken to assess the hypoglycemic, hypolipidaemic and cytoprotective effects of ethanolic extract of red and white lotus seeds in male Sprague-Dawley rats. It was carried out in different animal models and compared with respective reference drug. The extracts of red and white lotus seeds were administered at the rate of 600 mg kg-1 for 28 days.

The experiment was carried out in two hundred and seventy six rats. The blood glucose, serum total cholesterol, serum HDL, serum triglycerides and plasma free fatty acids was estimated on 0, 7th, 14th, 21st and 28th day of treatment in the respective animal models. The LDL cholesterol was calculated with help of formula.

Type I diabetic rats treated with lotus seeds (red and white) extract showed significant reduction in blood glucose from 14th day onwards and in case of metformin from 7th day onwards. On 28th day oral glucose tolerance test and on 29th day liver glycogen and GLUT2 gene expressions were carried out. A significant increase in liver glycogen and reduction in GLUT2 gene expression was observed in all the treated groups. Glucose tolerance also showed significant improvement in all the treated group. In case of type II diabetic rats there was significant reduction in glucose levels from 21st day of treatment in extracts treated groups. Metformin treated group showed significant reduction from 7th day onwards. There was significant increase in liver glycogen, GLUT4 gene expression and glucose tolerance in all the treated groups. The pancreatectomized rats showed significant reduction in blood glucose levels from 21st day onwards in all the treated groups. Histopathological examination of pancreas revealed that there was significant proliferation of beta cells and increasing number of active cells was seen in all the treated groups. Hypercholesterolemic animals treated with lotus seed extract showed significant reduction in total cholesterol and LDL levels from 14th day treatment onwards. In case of simvastatin treated group significant reduction was noticed from 7th day treatment onwards. A significant increase in HDL level was observed on 28th day and from 7th day in extract and simvastatin treated groups respectively. A significant reduction in liver total lipid was noticed in all the treated group on 29th day. Hypertriglyceridemic animals treated with the extract showed significant reduction in triglycerides from 14th day treatment onwards. In case of fenofibrate significant reduction was observed from 7th day treatment onwards. The free fatty acid levels reduced significantly from 21st and 14th day onwards for extract and fenofibrate treated groups respectively. Liver total lipid level showed significant reduction in all the treated groups on 29th day. Pancreatitis was induced by repeated administration of alloxan in rats. They were treated with lotus seed extracts for 28 days. Pancreas was collected after sacrificing the animals for estimation of superoxide dismutase, catalase, and glutathione peroxidase and lipid peroxidation. The superoxide dismutase, catalase and glutathione peroxidase levels increased in pancreas of extract and metformin treated group. It was significant from 14th day treatment onwards. There was a significant reduction in lipid peroxidation level in red and white lotus seed extract treated group from 21st and 14th day treatment respectively. In case of metformin treated group significant reduction was noticed from 14th day of treatment. Histopathological examination of pancreas revealed islet hyperplasia with more number of active cells in a duration dependent fashion in all the treated groups. From the study, it can be concluded that both red and white lotus seed extract have hypoglycemic, hypolipidaemic and cytoprotective effects. However, the effects are less than that of respective reference drug.