Change in the contents of fatty acids and antioxidant capacity of purslane in relation to fertilization

Abstract

Purslane (Portulaca oleracea L.) is considered as a vegetable rich in nutraceutical compounds (fatty acids and antioxidants); however, abiotic factors like nitrogen (N), phosphorus (P), and potassium (K) fertilization can influence the concentrations of these compounds. The objective of the study was to evaluate the effect of NPK fertilization on the nutraceutical content of purslane on two harvest dates (27 and 42 days after emergence). The doses were: N: 0, 100, 200 and 300 kg N ha−1; P: 0 and 60 kg P2O5 ha−1; K: 0 and 80 kg K2O ha−1. Nitrogen application at 100 kg N ha−1 decreased total phenolics (TPC), flavonoids (TFC), β-carotene (BC), and chlorophylls in foliage purslane; however, these contents increase at higher doses, up to 300 kg N ha−1, without surpassing the initial contents with 0 kg N ha−1; the ascorbic acid (AAC), palmitic and stearic acids, and antioxidant activity (DPPH scavenging capacity) decrease gradually; and linoleic and α-linolenic acids increased with the applied N. The application of P and K decreased TFC and AAC, but BC increased with the applied K. The TFC increased as well as linoleic and α-linolenic acids by the first harvest, while BC, chlorophylls, and palmitic and stearic acids increased by the second harvest. This study shows the possibility of maximizing the nutraceutical content and the antioxidant capacity of purslane through fertilization, besides providing an alimentary and medicinal panorama with these compounds.