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

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 beta-carotene, chlorophyll a and b, total phenolic compounds (TPC), total flavonoids, and total flavonols was evaluated. Additionally, DPPH center dot scavenging activity and ferrous iron (Fe+2) chelating activity of these extracts were also measured. The acetone extract had the highest amounts of beta-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 center dot scavenging activity (IC50 = 57.23 mu g mL(-1)) compared to methanol (IC50 = 65.80 mu g mL(-1)) and water (IC50 = 71.47 mu g 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 center dot scavenging activities of the purslane extracts and their content of TPC, flavonoid, flavonol, beta-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 beta-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.