Abstract: Polyphenols are products of the secondary metabolism of plants. They are common constituents of plant food and beverages as tea and wine. The two main of polyphenols are phenolic acids and flavonoids. Phenolic acids are divided into hydroxybenzoic acids and hydroxycinnamic acids. Common subfamilies of flavonoids are flavonols, flavanones, flavones, flavan-3-ols (catechins), anthocyanins, chalcones, and isoflavones. During the last decades numerous studies have evidenced about health effects of polyphenols that arise mostly from the antioxidative activity.
Diabetes mellitus is a chronic disease caused by an inherited or acquired deficiency in insulin secretion and by decreased responsiveness of the organs to secreted insulin, which results in increased blood glucose levels. a-Glucosidase [EC. 3. 2. 1. 20] is a membrane-bound enzyme located at the epithelium of the small intestine, which catalyses the cleavage of glucose from disaccharides. Inhibitors of this enzyme may be effective in retarding carbohydrate digestion and glucose absorption to suppress hyperglycaemia.
Polyphenols contained in medicinal plants, which are used in the treatment of diabetes, may explain their therapeutic activity. They may affect glycemia through different mechanism, but mainly due to an inhibition of a-glucosidase and/or a-amylase.
The aim of our study was to derive a quantitative structure-activity relationship (QSAR) analysis for the a-glucosidase inhibition potential of polyphenols by the application of a series of molecular descriptors that encode physicochemical and quantum-chemical properties, as well as two-dimensional (2D) and three-dimensional (3D) structural features of the molecules in question. The QSAR models, thus obtained, could provide some insights into the mechanism of action of polyphenols as inhibitors of a-glucosidase.

Brief Biography of the Speaker:
Vesna Rastija graduated from the Faculty of Education in Osijek (biology and chemistry) in 1994. After the graduation she taught the chemistry and biology in elementary school for a three years. Since 1997 she has been employed as a teaching assistant of Chemistry on Faculty of Agriculture in Osijek. Vesna has made my master thesis on the Institute “Rudjer Boskovic” in Zagreb in area of inorganic and structural chemistry, and 2001 earned a Master of Science degree at the Faculty of Science (University of Zagreb). She defended a doctoral thesis on Faculty of Pharmacy and Biochemistry in Zagreb and obtained a doctoral degree (science, chemistry) on 14 March 2007 at the Faculty of Science (University of Zagreb). Title of the doctoral thesis was: “Chromatographic analysis of polyphenols in wines from Croatia”.
She is currently employed as assistant professor at Department of Chemistry, Faculty of Agriculture Osijek, University of J. J. Strossmayer Osijek, Croatia.
Until now she has published a 14 journal articles. She is a member of Croatian Chemical Society.