Raw garlic aqueous extract (GE) has ameliorative actions on the renin-angiotensin system in type-1 diabetes mellitus (DM); however its effects on plasma and kidney angiotensin I converting enzyme type-1 (ACE-1) and angiotensin II (AngII) require further elucidation. This study investigated the effect of GE on plasma and kidney ACE-1 and AngII concentrations and in relation to systemic and renal clearance indicators significant to blood pressure (BP) homeostasis in early streptozotocin- (STZ-) induced type-1 DM. Normal rats (n = 10) received 0.5 mL normal saline (NR/NS), diabetic rats (n = 10) received 0.5 mL NS (DR/NS), and treated diabetic rats (n = 10) received 50 mg/0.1 mL/100 g body weight GE (DR/GE) as daily intraperitoneal injections for 8 weeks. Compared to NR/NS, DR/NS showed a significant increase in plasma ACE-1 and AngII and conversely a decrease in kidney ACE-1 and AngII. These changes were associated with an increase in BP and clearance functions. Alternatively and compared to DR/NS, DR/GE showed normalization or attenuation in plasma and kidney ACE-1 and AngII. These GE induced rectifications were associated with moderation in BP elevation and renal clearance functions. Garlic attenuates modulations in plasma and kidney ACE-1 and AngII, in addition to BP and renal clearance function in type-1 DM.

The anti‐diabetic and antioxidant effects of oral administration of aged garlic extract (AGE) were studied in diabetic rats. Diabetes was induced by IP injection of streptozotocin (60mg/kg, STZ), and a fasting blood sugar >300 mg/dl indicated diabetes. AGE (Wakunaga‐Kyolic, USA) was administered orally at a dose of 600 mg/kg daily for 8 weeks. Diabetic rats were divided into 2 groups, diabetic control and AGE‐treated diabetic. A normal, saline‐treated, control group was also included. STZ‐induced diabetic rats lost significant weight during the experiment with AGE‐treated rats maintaining their initial weights. Blood glucose as well as serum cholesterol and triglycerides were significantly elevated in diabetic rats, and significantly lowered by AGE treatment. Serum insulin level was decreased nearly 30‐fold in diabetic rats and was increased significantly by AGE treatment; while serum fructosamine was increased about 2.5 fold in diabetic rats with a marked decrease in AGE‐treated diabetic rats. Significant decreases in total antioxidant levels (26‐39%) and catalase activity (50‐71%) were observed in serum, kidneys and livers of diabetic rats with significant recovery in AGE‐treated animals. In contrast, lipid peroxidation (MDA levels) increased in kidneys (57%) and livers (44%) of diabetic rats and was significantly lowered in AGE‐treated diabetic rats. Protein levels in serum, liver and kidneys were significantly lowered in diabetic rats with increased levels in AGE‐treated rats. Thus, oral AGE treatment was effective in ameliorating oxidative stress and other indicators of diabetes in STZ‐induced diabetic rats. The study was supported by KU grant #SL 06/13.