Biochemical Evaluation of Antioxidant properties of A Zn-Avicularin Complex Studied in High Fat Diet Fed- Low Dose Streptozotocin Induced Experimental Type 2 Diabetes in Rats

Abstract

Zinc is an essential trace element next to iron in the human system. Its central role in the synthesis, storage, and functional aspects of insulin is well established. Ever since the insulin-mimetic activity of zinc was recognized, several zinc complexes have been synthesized and studied for their antidiabetic and other pharmacological properties. However, its clinical application is narrow due to poor absorption, toxicity associated with prolonged use. Hence, endeavors are being made for the advancement of zinc complexes with various organic ligands of known therapeutic values to avert the toxicity of zinc. Avicularin, a bioactive flavonol originally isolated from the leaves of Polygonum aviculare Linn., is a quercetin derivative in which the α-L-arabinofuranosyl residue is linked at position 3 of quercetin via a glycosidic linkage. It is non-toxic and reported to possess a wide range of pharmacological properties. Though Avicularin is a glycoside of quercetin, it is hydrophilic while quercetin is lipophilic and hence they may differ in absorption rate. In view of the beneficial and pharmacological properties bestowed with Avicularin, recently we have reported the synthesis, spectral characterization and evaluation of antidiabetic properties of a new Zn-Avicularin complex in HFD fed low dose STZ induced experimental type 2 diabetes in rats. In the present study, an attempt has been made to evaluate the antioxidant properties of the Zn-Avicularin complex by analyzing the levels of oxidative stress markers such as lipid peroxides, hydroperoxides and protein carbonyls in the plasma, pancreas, hepatic and renal tissues. The status of enzymatic antioxidants such as SOD, catalase, Glutathione peroxidase as well as non-enzymatic antioxidants such as vitamin C, vitamin E and ceruloplasmin were assayed. Oral administration of the Zn-Avicularin complex at a concentration of 5mg/kg b.w/rat/day for 30 days significantly ameliorates the hyperglycemia-induced oxidative stress in the diabetic groups of rats and the efficacy was comparable with metformin.