Modulatory effect of Calendula officinalis on altered antioxidant status and renal parameters in diabetic rats

Diabetes mellitus, a most common endocrine disorder is the major cause of ill health worldwide (1). The disorder will continue to grow globally due to an aging population, growth of population size, urbanization, high prevalence of obesity and sedentary life style (2). Defect in insulin secretion from ß-cells of pancreas and/or insulin action on the central and peripheral organs are often primary causes of manifestation of disease (3). Experimental diabetes in animals provides considerable insight into the physiological and biochemical derangement in important vital organs of the body particularly in renal diseases. Studies showed diabetic complications are primarily due to increased non-enzymatic and progressive glycation of proteins with consequently increased formation and accumulation of glucose derived advanced glycation end products (AGEs) (4,5) in tissue leading to oxidative damage. Further persistent decrement in the level of insulin adversely deranges the carbohydrate and lipid metabolism in mammalian tissues leading to secondary complications. Application of phytochemicals for the treatment of various ailments has been used since dawn of civilization. Herbal drugs are undoubtedly attractive and reliable alternative for management of diseases due to their easy accessibility, efficacy and importantly being natural herbs are considered to be safe (6). Ethnobotanical reports suggest that more than 800 plants to Abstract Calendula officinalis (Family Compositae) flowers are recognized as safe substance for food use by Food and Drug Administration. Present study was aimed to determine the modulatory effect of floral extracts of C. officinalis administrations on mean blood glucose (MBG), per cent glycosylated hemoglobin (HbA1c), lipid profile [(total cholesterol (TC), triglycerides (TG), low and high density lipoproteins (LDL, HDL)], antioxidant and renal parameters in streptozotocin (STZ) induced diabetic rats. Increased (P < 0.05) levels of MBG and HbA1c fraction indicate the induction of diabetes in rats. Enhanced (P < 0.05) TC, TG, LDL, total oxidant status (TOS), oxidative stress index (OSI), malondialdehyde (MDA) levels, and renal indices were observed in blood of diabetic rats. However, levels of HDL, protein profile, total antioxidant status (TAS), glutathione (GSH), total thiols (TTH) and activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione-s-transferase (GST) and glucose-6-phosphate dehydrogenase (G6PDH) were significantly reduced in diabetic rats. Repeated administrations of ethanolic floral extract of C. officinalis reduced the enhanced levels of MBG, HbA1c and TC while restored OSI, TTH, GSH, CAT, SOD, GST and MDA levels; it also increased activities of G6PDH and GPx in diabetic rats compared to untreated diabetic rats. Hypoglycemic, hypolipidemic, restored antioxidant level, and reduced altered renal functions by the floral extract of C. officinalis in diabetic rats. Further, the modulatory effect was better in aqueous as compared to ethanolic floral extract of C. officinalis.