Antioxidant properties of green Allium vegetables

Abstract

This study was aimed to evaluate the antioxidant activities of some allium vegetables. Methanolic (80%) extracts of edible parts of green onion, garlic, leek and kormen (Allium scorodoprasum L. subsp. rotundum (L.)) were prepared by ultrasound-assisted extraction, which was followed by evaluation of total phenolics and antioxidant activity. Also, color, dry matter, soluble solids of the samples were determined. In this study, seven different samples of green onion, garlic and leek grown in Samsun (Turkey) and seven different kormen grown in Amasya (Turkey) were analyzed. Total phenolic contents (as mg gallic acid equivalents g(-1) on dry weight basis, mg GAE g(-1) DW) of samples followed the hierarchic order: Green parts of onion (7.43 +/- 0.95) > green parts of garlic (6.92 +/- 2.79) > green parts of kormen (6.33 +/- 0.40) > green parts of leek (4.78 +/- 1.23) > white parts of onion (2.96 +/- 1.20) > white parts of leek (2.13 +/- 0.82) > white parts of garlic (1.97 +/- 0.59) > white parts of kormen (1.14 +/- 0.20). FRAP values (as mmol Fe2+ g(-1) on dry weight basis) were ordered as follows: green parts of kormen (20.66 +/- 10.65) > green parts of onion (16.67 +/- 3.15) > white parts of onion (12.62 +/- 5.37) > green parts of garlic (5.94 +/- 2.56) > green parts of leek (4.09 +/- 2.70) > white parts of kormen (2.67 +/- 1.25) > white parts of leek (1.71 +/- 1.23) > white parts of garlic (1.64 +/- 0.99). Also, the average content of DPPH scavenging activity (the percentage of DPPH reduced by 14.3 mg mL(-1) extract) in samples were as follows: green parts of onion (84.31 +/- 11.23%) > green parts of kormen (67.69 +/- 10.24%) > white parts of onion (66.41 +/- 16.51%) > green parts of garlic (63.78 +/- 18.70%) > white parts of garlic (32.81 +/- 9.76%) > green parts of leek (29.02 +/- 13.83%) > white parts of kormen (15.67 +/- 6.37%) > white parts of leek (15.55 +/- 2.95%). As a result, the green parts of samples analyzed had higher antioxidant activity and total phenolics than the white parts.