Impact of extraction techniques on antioxidant capacities and phytochemical composition of polyphenol-rich extracts

In this work, impact of extraction methods (maceration, decoction, MAE, and UAE) on TPC, antioxidant activity, and the mass fraction of phenolics in several plant extracts (Punica granatum, Juglans regia, Moringa oleifera, and Cassia fistula) was investigated. The results showed that, despite the nature of matrix, the highest values of TPC in all samples were obtained by MAE as follows: PP (18.92 +/- 0.11), ML (15.19 +/- 0.11), HL (12.69 +/- 0.16), and WS (12.80 +/- 0.11) mg GAE g +/- 1 respectively, and exhibited potent antioxidant activity (from 0.28 +/- 0.01 to 5.34 +/- 0.02 mg GAE g +/- 1), representing sources of powerful antioxidants. The LC-MS2 analysis revealed a wide range of phenolics, highlighting their content in phenolic acids, flavonoids and lignans. The presence of different phenol molecules demonstrated that the extraction method had influence on phytochemical profile. Finally, due to its high extraction efficiency, MAE was the more effective extraction technique. (C) 2017 Elsevier Ltd. All rights reserved.