304 Document heading doi: 10.1016/S2221-6189(13)60149-3 Syringic acid, a novel natural phenolic acid, normalizes hyperglycemia with special reference to glycoprotein components in experimental diabetic rats Jayachandran Muthukumaran 2 , Subramani Srinivasan 1* , Rantham Subramaniyam Venkatesan 2 , Vinayagam Ramachandran 1 , Udaiyar Muruganathan 1 1 Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar - 608002, Tamil Nadu, India 2 Department of Biochemistry, Adhiparasakthi College of Arts and Science, G. B. Nagar, Kalavai, Vellore Dist - 632506, Tamil Nadu, India ARTICLE INFO ABSTRACT Article history: Received 10 July 2013 Received in revised form 19 August 2013 Accepted 26 August 2013 Available online 20 December 2013 Keywords: Syringic acid Diabetes mellitus Glycoproteins Alloxan *Corresponding author: Dr. S. Srinivasan, Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar - 608002. Tamilnadu, India. Tel: +91 04144 - 238343 Fax: +91 04144 -239141 E-mail: sivaseenu77@gmail.com 1. Introduction Diabetes is a prototypical, growing, costly chronic non- communicable disease (NCD) causing increasing morbidity and mortality worldwide, often disproportionately hurting the poor and young sub-populations in developing countries [1] . Globally there are 366 million people currently known to have diabetes which is estimated to grow to 552 million by 2030 with 80% of all people with diabetes living in the developing world [2] . An estimated 61.3 million people in India have diabetes and the number is projected to reach 101.2 million by 2030. The pathophysiology of diabetes involves a very complex cascade of several interrelated mechanism. Elevated blood glucose induced microvascular and macrovascular changes, such as atherosclerosis, retinopathy, nephropathy, coronary artery disease, cerebral vascular disease, and peripheral artery disease [3] , the reasons for injury related to hyperglycemia is increased polyol pathway flux, increased glycation of proteins (enzymatic or non enzymatic) and increased hexosamine pathway flux [4] . Among the above stated possibilities, glycosylation of proteins has been the prime subject of much interest. In the diabetic state, glucose is used by the insulin independent pathways, leading to the synthesis of oligosaccharide moieties of glycoprotein. Glycoproteins can be simply defined as proteins that have carbohydrate moiety covalently attached to their peptide portion. They have multiple and complex function and are found as enzymes, hormones, blood group substances and as constituents of extracellular membranes [5] . The commonest glycoproteins are those in which the carbohydrate is linked to the protein by glycosyl linkages, usually hexose, hexosamine, fucose and sialic acid, joined together covalently linked to polypeptide chain. Hyperglycemia in Objective: To evaluate the antidiabetic effect of syringic acid, a natural phenolic compound on the levels of glycoprotein components in plasma and tissues of alloxan induced diabetic rats. Methods: Diabetes was induced in male Wistar rats by a single intraperitoneal injection of alloxan (150 mg/kg b.w). Syringic acid (50 mg/kg b.w) was administered orally for 30 d. The effects of syringic acid on plasma glucose, insulin, C-peptide, plasma and tissue glycoproteins were studied. Results: Oral administration of syringic acid (50 mg/kg b.w) for 30 d positively modulates the glycemic status in alloxan induced diabetic rats. The levels of plasma glucose were decreased with significant increase of plasma insulin and C-peptide level. The altered levels of plasma and tissue glycoprotein components were restored to near normal. No significant changes were noticed in normal rats treated with syringic acid. Conclusions: The present findings suggest that syringic acid can potentially ameliorate glycoprotein components abnormalities in addition to its antidiabetic effect in experimental diabetes, further clinical studies are required to evaluate the use of syringic acid as an effective therapeutic agent for the treatment of diabetes mellitus. Journal of Acute Disease (2013)304-309 Contents lists available at ScienceDirect Journal of Acute Disease journal homepage: www.jadweb.org