Phytochemicals and Antioxidant Properties of Solvent Extracts from Purslane (Portulaca oleracea L.): A Preliminary Study

A systematic study was conducted about the solvent effect on the purslane total phenolic, flavonoid, alkaloid, carotenoid, saponin, vitamin E, and vitamin C contents as well as to evaluate their contribution to overall antioxidant activity. Among three solvents investigated, water could extract the highest levels of solid and saponin contents, whereas methanol was more effective for obtaining phenolic, flavonoid, and alkaloid compounds than other solvents. Meanwhile, ethanol was the best choice for extracting carotenoids and vitamin E. In various experimental models including DPPH radical scavenging activity, ABTS+ radical scavenging activity, and ferric reducing antioxidant power, methanol extract consistently showed significantly greater antioxidant activity than other extracts, while ethanol extract provided the most efficient inhibiting activity against ferrous chloride-induced oxidation of linoleic acid. In addition, the scavenging efficiency of ethanol extract toward DPPH and ABTS+ radicals was significantly higher than the water extract, and vice versa was the case for ferric reducing antioxidant power. Overall, methanol was found to be the most favorable solvent for the extraction of phenolic, flavonoid, and alkaloid compounds that are promising as natural antioxidants. However, different solvents may be used to extract specific antioxidant compounds with distinctive antioxidant activity.