Experimental evidence suggests that hyperglycaemia is commonly associated with hyperlipidaemia( Footnote 1 , Footnote 2 ). The present study was undertaken to investigate the effect of an aqueous extract of Ajuga iva L. Schreiber (Lamiaceae; Ai) on blood glucose, serum and lipoprotein lipid profiles and lecithin:cholesterol acyltransferase (LCAT) activity in rats with streptozotocin-induced diabetes.
Twelve rats with diabetes were divided into two groups that were fed a casein diet either with or without an Ai supplement (5 g/kg diet) for 4 weeks. Experimental diabetes was induced by intraperitoneal injection of streptozotocin as a single dose of 60 mg/kg body weight. HDL subfractions were separated by differential dextran sulphate–MgCl2 precipitation and LCAT activity was determined by conversion of [3H]cholesterol (unesterified; UC) to [3H]cholesteryl esters (CE).
Ai treatment significantly decreased glycaemia (−41%) and liver total cholesterol (TC; −33%), TAG (−30%) and phospholipids (PL; −47%). In the Ai-treated rats compared with the untreated rats hypocholesterolaemia (−33%) and hypotriacylglycerolaemia (−72%) were observed with a concomitant reduction in LDL-HDL1-cholesterol (−50%), VLDL-cholesterol (−56%) and VLDL-TAG, whereas HDL-cholesterol remained unchanged for both groups. Moreover, plasma apoB concentration was 2-fold lower, while that of apoA was 2.4-fold higher.
LCAT activity was 1.5-fold higher in the Ai-treated rats than in the untreated rats. Moreover, HDL3-PL and HDL3-UC were decreased by 57% and 70% respectively, whereas HDL2-CE was similar for both groups. Also, the atherogenic ratios TC:HDL-cholesterol, VLDL-LDL-cholesterol:HDL-cholesterol and apoB:apoA were decreased by 31%, 46% and 79% respectively in Ai treated rats v. untreated rats.
These results suggest that Ai treatment is effective in decreasing the level of glycaemia and attenuating dyslipidaemia in rats with streptozotocin-induced diabetes by reducing plasma lipids and inversely increasing reverse cholesterol transport.
