Antioxidative compounds of Brassica spp. (cabbage)

Abstract

Dietary antioxidants present in fruits and vegetables contribute to the defense mechanisms against oxidative stress. Brassica spp. are among the vegetables that are rich in natural antioxidative compounds. To encourage the Brassica spp. consumption through nutritional counseling among the public, it is important to determine which species have the highest antioxidant compounds and introduce them regularly into the diet. Thus, this study was conducted to determine the concentration of ascorbic acid, a-tocopherol and carotenoid, as well as ascorbate peroxidase (APX), guaiacol peroxidase (gPOD) and catalase (CAT) specific activities in three different Brassica spp. namely Brassica oleracea var. capitata f. rubra (red cabbage), Brassica oleracea var. capitata f. alba (white cabbage) and Brassica rapa var. pekinensis (Chinese cabbage). The carotenoid concentration varied from 1.054±0.093 to 3.733±0.284 mg/g fwt. Among three Brassica spp., the maximum carotenoid concentration was detected in red cabbage. Red cabbage also contained almost 10-fold and 3-fold higher concentration of ascorbic acid (111.717±11.715 µgig fwt) and a-tocopherol (8.201±0.206 µg/g fwt), respectively compared to Chinese and white cabbage. Interestingly, red cabbage also showed higher specific activity of gPOD (504.165±77.388 units/mg protein), which was comparable to those of white cabbage and 9.5-times higher than Chinese cabbage. Similarly, APX (120.691±13.164 units/mg protein) and CAT (0.906±0.128 units/mg protein) specific activities were also observed higher in red cabbage. The results indicated that red cabbage contained high natural anti oxidative compounds and may provide good sources of dietary natural antioxidants compared to the Chinese and white cabbage.