Phytochemical characterization and radical scavenging activity of Portulaca oleraceae L. leaves and stems

The present work aimed to proceed to the phytochemical characterization of purslane (Portulaca oleracea L.) and study of its antioxidant activity. Different samples were analyzed for their moisture and fat content, fatty acids, organic acids and phenolic compound composition and the scavenging effect of DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals was evaluated. Water was the major constituent of purslane stems (average 90.5%) and leaves (average 91.8%), while fat values varied from 0.11% to 0.57%. Twenty seven fatty acids were found in the leaves samples, being linolenic acid the most abundant, ranging from 27.7 to 39.1%, followed by palmitic (19.3-24.3%) and oleic acids (11.6-19.5%). Five different organic acids were detected namely fumaric, aconitic, citric, malic and oxalic acids. oxalic and citric acids were the most abundant, while aconitic acid was present in the lowest content. Two phenolic acids were identified and quantified: 3-caffeoylquinic and 5-caffeoylquinic acids. Leaves presented higher amounts of phenolic compounds, being 3-caffeoylquinic acid more abundant in leaves and 5-caffeoylquinic acid in stems. The leaves revealed to be the part with highest antioxidant potential. (C) 2009 Elsevier B.V. All rights reserved.