Determination of natural phenols after microwave-assisted extraction

Abstract

Natural phenols are synthetized by large group of plants where they play an important role in plant metabolism and protection against pests. These compounds, in addition to being indispensable in plant metabolism, also exhibit complex biological activity in humans for what they are constantly in the focus of scientific interest. The aim of this study was to modify standard spectrophotometric method for polyphenols determination. Modification included application and optimization of microwave-assisted extraction which significantly reduced sample preparation time and improved extraction yields. Furthermore the goal of this study was to improve determination sensitivity by applying differential spectrophotometric measurement. Optimized analytical method was implied to determine anthocyanins, neutral and total polyphenols in different fruit and vegetable samples, as well as in cakes remaining after oil extraction of several oilseeds. Purification of extracts and fractionation of polyphenols to different classes was performed by using solid phase extraction. Individual acidic and neutral polyphenolic compounds were identified in plant extracts by thin layer chromatography.