Fayçal DJELLOULI

Portulaca oleracea (Po) has been used as one of the traditional edible and medicinal plant in Algeria to treat diabetes and enhancing immunity. The aim of the present study was to investigate the possible antihyperglycemiant and hypolipemiant effects of Po lyophilized aqueous extract, in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced in male Wistar rats (n=12), weighing 263±5g, by a single intraperitoneal injection of STZ (60mg/kg body weight). Diabetic rats were divided into two groups. The untreated group received a 20% casein diet (D) and the treated group received the same diet supplemented with Po lyophilized aqueous extract (1 g/100 g diet) (DPo), for 4 weeks. According to thin layer chromatography assay, the main chemical groups detected are flavonoids, alkaloids, and terpenoids. During all the experiment in spite of similar food intake in the 2 groups, there was a significant decrease in the body weight. At d28, in Po treated vs untreated diabetic group, glycemia and glycosylated haemoglobin (HbA1c) were reduced by 61% and 41%, respectively, whereas insulinemia was similar. Plasma cholesteryl esters (CE), triacylglycerols (TG) and phospholipids (PL) concentrations were decreased by 48%, 53% and 62%, respectively. The hypolipidemic effect induced by Po extract was due to the reduction of total cholesterol (TC) in VLDL (-28%), LDL-HDL1 (-51%) and C-HDL3 (-21%), and a decrease of TG in VLDL (-71%), LDL-HDL1 (-68%) and HDL2 (-30%). Quantitatively, VLDL, LDL-HDL1, HDL2 and HDL3 lipoproteins mass was respectively 2.9-, 4.1-, 1.5- and 2.5-fold lower and concomitant with the reduced levels of unesterified cholesterol (UC) (-55%), CE (-17%) and -PL (-72%) in VLDL fraction, and UC (-36%), -CE (-56%) and PL (-82%), in LDL-HDL1. Po treatment improved lecithin:cholesterol acyltransferase (LCAT) activity by 48% and its cofactor-activator, the plasma apolipoprotein (apo) A-I by 52%.. HDL3-UC (acyl group acceptor) and -PL (enzyme substrate) were diminished respectively by 47% and 82%, whereas HDL2-CE concentrations (product of LCAT reaction) were increased by 44%. In STZ-induced diabetic rat, Portulaca oleracea lyophilized aqueous extract possesses antihyperglycemiant and hypolipemiant effect by improving lipoprotein profiles. Po extract may be useful in the prevention and treatment of diabetes and dylipidemia.