A PHYTOCHEMICAL STUDY AND ANTIOXIDANT POTENTIAL OF PORTULACA OLERACEA L. (PURSLANE) GROWN WILD IN BULGARIA AND GREECE

Portulaca oleracea L. (purslane) is an edible plant with cosmopolitan distribution, traditionally consumed in the diet rich in green leafy vegetables. Methanol-aqueous extracts of purslane aerial parts from Bulgarian (POB) and Greek (POG) origin were evaluated for their antioxidant potential using radical scavenging activity and ferric reducing power. The studied accessions were also analyzed for total flavonoids, polyphenols and polysaccharides by pharmacopoeia) spectrophotometric methods. Both purslane extracts (POB and POG) revealed equal radical scavenging activity with IC50 values: 1.98 and 2.00 mg mL(-1) (DPPH), and 0.88 and 0.92 mg mL(-1) (ABTS), respectively, as well as similar polyphenol contents. POB had higher ferric reducing ability (0.16 mM Trolox equivalent TE) comparable with positive control chlorogenic acid (0.17 mM TE). The POG showed higher total flavonoids level (0.31 +/- 0.01%), but lower polysaccharides content (0.19 +/- 0.02%) was determined. In addition, the optimal extraction conditions for the highest yields of extracts, polyphenols and saponins were evaluated. It was found that the extraction by stirring at 80 degrees C gave the highest percentage yield of 16%, while the maximum polyphenols (3.45% +/- 0.83) and saponins (9.15% +/- 0.17) contents were achieved by Soxhlet extraction. P. oleracea with Bulgarian and Greek provenance have a significant potential against oxidative stress.