Carotenoid pigment composition, polyphenol content, and antioxidant activities of extracts from orange-colored Chinese cabbage

Abstract

We investigated the carotenoid pigment composition in orange-colored Chinese cabbage (OC) (Brassica rapa; cultivar (cv), Orange queen) and (normal) Chinese cabbage (NC) (B. rapa; cv, Yūki), and evaluated the antioxidant activities of their carotenoid and phenolic extracts. Although the major carotenoid pigments in NC are lutein and β-carotene, OC contained 7Z, 9Z, 7’Z, 9’Z tetra-cis-lycopene (prolycopene) and phytoene as the major carotenoid pigments along with β-carotene. The total carotenoid content of extracts from OC was two-fold higher than the extracts from NC. The 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging activity of carotenoid extracts from OC [169 ± 2 μmol Trolox equivalent/100 g dry weight. (DW) (average ± SD)] was significantly higher than the carotenoid extracts from NC (132 ± 7 μmol Trolox equivalent/100 g DW) (P < 0.001). Moreover, the total phenols of methanolic extracts from OC (387 ± 11 mg/100 g DW) was significantly higher than the methanolic extracts from NC (263 ± 2 mg/100 g DW) (P < 0.001), and the superoxide anion radical-scavenging (SOD-like) activities of methanolic extracts from OC (70 ± 2%) were also higher than the methanolic extracts from NC (61 ± 2%) (P < 0.001). These results suggest that OC contains large amounts of carotenoid and phenolic compounds with radical-scavenging activity in comparison to NC.