Chemical Properties and Antioxidant Activity of Different Extracts from Purslane (Portulaca Oleracea L.)

Abstract

Purslane (Portulaca oleracea L.) has been known as a medical herb with valuable nutritional and pharmacological properties. Herein, water, methanol, and acetone extracts were prepared from two morphologically different purslane samples, thereafter their content of β-carotene, chlorophyll a and b, total phenolic compounds (TPC), total ‎flavonoids, and total flavonols was evaluated. Additionally, DPPH• scavenging ‎activity and ferrous iron (Fe+2) chelating activity of these extracts were also measured. The acetone extract had the highest amounts of β-carotene (14.16 mg g-1 DW), chlorophyll a (40.46 mg g-1 DW), chlorophyll b (9.94 mg g-1 DW), TPC (51.01 mg GAE g-1 DW), ‎flavonoids (133.23 mg RE g-1 DW), and flavonols (46.94 mg RE g-1 DW). Whereas the lowest values were observed in the water extract, as 0.03 mg g-1 DW, 0.03 mg g-1 DW, 0.06 mg g-1 DW, (34.24 mg GAE g-1 DW, 10.98 mg RE g-1 DW, 3.28 mg RE g-1 DW, respectively. The acetone extract also showed higher DPPH• scavenging ‎activity (IC50 = 57.23 µg mL-1) compared to methanol (IC50 = 65.80 µg mL-1) and water (IC50 = 71.47 µg mL-1) extracts. Regarding the ferrous iron (Fe+2) chelating activity, methanol extract exhibited the highest value followed by water and acetone extracts, being 12.78, 10.20 and 6.08%, respectively. A positive correlation was detected between the DPPH• scavenging activities of the purslane extracts and their content of TPC, flavonoid, flavonol, β-carotene, chlorophyll a, and chlorophyll b. On the other hand, there was no significant correlation between chelating activity of the extracts and their content of β-carotene, chlorophyll a, TPC, flavonoids, flavonols, and DPPH scavenging activity. Purslane extracts could be suggested as a natural antioxidant substance for many pharmaceutical and food applications.