In the present study, the hypoglycaemic potentials of ginger (Zingiber officinale) were studied in rats. An aqueous extract of raw ginger was administered daily (500 mg/kg, intraperitoneally) for a period of 7 weeks to streptozotocin (STZ)-induced diabetic rats. Fasting blood serum was analysed for blood glucose, cholesterol and triacylglycerol levels. The STZ-injected rats exhibited hyperglycaemia accompanied with weight loss, indicating their diabetic condition. At a dose of 500 mg/kg, raw ginger was significantly effective in lowering serum glucose, cholesterol and triacylglycerol levels in the ginger-treated diabetic rats compared with the control diabetic rats. The ginger treatment also resulted in a significant reduction in urine protein levels. In addition, the ginger-treated diabetic rats sustained their initial weights during the treatment period. Moreover, ginger decreased both water intake and urine output in the STZ-induced diabetic rats. The present results indicate that raw ginger possesses hypoglycaemic, hypocholesterolaemic and hypolipidaemic potential. Additionally, raw ginger is effective in reversing the diabetic proteinuria observed in the diabetic rats. Thus, ginger may be of great value in managing the effects of diabetic complications in human subjects.

Oxidative damage by free radicals has been implicated in the pathogenesis of vascular disease in diabetes and hypertension. In the present study, the total antioxidant status in diabetic and hypertensive rats before and after treatment with garlic (Allium sativum) was determined. The total serum antioxidants were measured by a modified method reported earlier by Miller and coworkers. The reproducibility of the assay was confirmed by determining standard curves for the known antioxidants: trolox (a stable analog of vitamin E), glutathione and vitamin C with interassay correlation coefficients (R2, n = 10 in triplicate) of 0.9984, 0.9768 and 0.987, respectively, confirming the reliability and reproducibility of the assay. This assay was then used to determine total serum antioxidant levels of streptozotocin-induced diabetic rats and two-kidney one-clip hypertensive rats both before and after 3 weeks of treatment with an aqueous extract of garlic (500 mg/kg IP daily). The serum antioxidant levels of rats after 3 weeks of treatment were significantly higher (P < .001) than the pretreatment levels in both diabetic and hypertensive rats. The increased serum antioxidant levels were paralleled by a decrease in serum glucose in the garlic-treated diabetic rats and lowered systolic blood pressure in the garlic-treated hypertensive rats. We conclude from our study that (i) total antioxidants can be measured by a simple, reproducible, reliable assay and (ii) the total antioxidant status can be significantly improved by treatment with garlic.

In this study, the hypoglycemic effects of a raw aqueous extract of ginger (Zingiber officinale) were studied in mildly and severely diabetic rats. Diabetes was induced in rats by the administration of streptozotocin (60 mg/kg). After one week, fasting serum glucose levels indicated that the diabetic rats could be divided into two groups: mildly diabetic (serum glucose ≅ 200 mg/dl) and severely diabetic (≥ 350 mg/dl). A raw aqueous extract of ginger was administered daily (500 mg/kg, intraperitoneally) for a period of seven weeks to both groups of diabetic rats. Both ginger‐treated diabetic groups showed a significant decrease in serum glucose level during the treatment period when compared to the diabetic control. The normal and treated mildly diabetic rats gained weight similarly while the treated severely diabetic rats nearly maintained their starting weights suggesting that ginger treatment protected the rats against characteristic diabetic weight loss. As for water intake, the treated mildly diabetic rats had a water intake similar to normal rats, while the treated severely diabetic rats increased their water consumption almost 5‐fold over the experimental period similar to diabetic control animals. These results indicate that raw ginger possesses hypoglycemic potential in both mildly and severely diabetic rats. In addition, raw ginger is effective in preventing the weight loss normally observed in diabetic rats. Thus, ginger may be useful in prevention of the progression of diabetes in both mild and severe conditions. This work was partially supported by Kuwait University College of Graduate Studies.

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