Antihyperglycemic and Antihyperlipidemic Evaluation of Zingiber officinale, Anethum graveolens and Citrullus colocynthis Extracts with Different Polarities in Streptozotocin-Induced Diabetic Rats

Zingiber officinale (ginger,II), Citrullus colocynthis (CC, III) and Anethum graveolens (dill, IV) are functional medicinal plants containing beneficial compounds and some evidence exists on their anti-diabetic, anti-inflammatory and hypolipidemic activities. The objective of this study was to evaluate the antihyperglycemic and antihyperlipidemic potential of various extracts of these plants with different polarities in experiments on streptozotocin-induced diabetic rats. Test animals (n = 112) were randomly divided into control, diabetic, diabetic+chloroform extract, diabetic+carbon tetrachloride extract, diabetic+hydroalcoholic extract, and diabetic+aqueous extract groups. Rats were made diabetic by a single injection of streptozotocin (STZ, 60 mg/kg). The plant extracts were daily administered (100 mg/kg, i.p.) for 3 weeks. Serum glucose and lipid levels were measured at different weeks. All extracts of ginger and dill as well as carbon tetrachloride and hydroalcoholic extracts of CC significantly reduced serum glucose level in diabetic groups. In addition, some plants extracts approppriately and significantly improved serum lipid levels including triglyceride, total cholesterol, HDLcholesterol, and LDL cholesterol in diabetic rats. According to extract polarities and components, all ginger extracts exerted hypoglycemic effect, however, hydroalcoholic extract showed the best potential to appropriately modify serum lipids in diabetic condition. In addition, hydroalcoholic extracts of C. colocynthis and A. graveolens had the best anti-diabetic potential which could be related to better extraction of bioactive components by polar or non-polar organic and aqueous solvents from these medicinal herbs.