581PROTECTIVE EFFECT OF CAFFEIC ACID AND 18 Β -GLYCYRRHETINIC ACID AGAINST STREPTOZOTOCIN–NICOTINAMIDE INDUCED DIABETESDiabetes mellitus is associated with the production of reactive oxygen species and consequently oxidative stress. Diabetes was induced in rats by a single intraperitoneal (i.p) injection of Streptozotocin (65 mg/kg, STZ) in overnight fasting rats followed by the i.p administration of Nicotinamide (110 mg/kg, NIC) after 15 minutes. Caffeic acid (40 mg/kg/body weight) and 18β-glycyrrhetinic acid (100mg/kg/body weight) were orally administered to diabetic rats for a period of 30 days. Liver and kidney function tests, total cholesterol, triglyceride, low density lipoprotein-cholesterol (LDL-C), very low density lipoprotein-cholesterol (VLDL-C), and malondialdehyde (MDA) were significantly increased, whereas high density lipoprotein-cholesterol (HDL-C) and Antioxidants (glutathione reductase (GR), glutathione peroxidase (GPx), total antioxidant (TAO), catalase , and superoxide dismutase (SOD)) were decreased significantly in diabetic rats. Though the diabetic rats treated with caffeic acid and 18β-glycyrrhetinic acid individual exerts beneficial effects in all the biochemical parameters in diabetic rats while the combined treatment with caffeic acid and 18β-glycyrrhetinic acid normalized all the above-mentioned biochemical parameters in STZ-induced diabetic ratsdr_fzahran@yahoo.comResearch632015Diabetes, caffeic acid,18β-glycyrrhetinic acid,Streptozotocin,AntioxidantsZahran F.M,Al-Hussaini A.S, El-shehabi M.EChemistry Department, Faculty of Science, Zagazig University, Egypt,Chemistry Department, Faculty of Science, PortSaid University, Egypt,Chemistry Department, Faculty of Science, PortSaid University, Egypt