Phytochemicals and antioxidant activity in four varieties of head cabbages commonly consumed in China

Head cabbage (Brassica oleracea var. capitata) is a cruciferous leafy vegetable consumed commonly in China. It has been suggested that diets rich in cabbages play an important role in disease prevention. The phytochemicals as well as antioxidant activity of four typical varieties of head cabbages in China were systematically investigated. Sinapic acid was the most abundant phenolic acid in all samples followed by iso-ferulic acid. Most phenolic acids in red head cabbage were significantly higher than in other head cabbages. The 5-CH3-H4 folate contents in all samples were much higher than folate. Conical head cabbage contained the highest amount of folic acids while red head cabbage had the lowest. Cyanidin was the only anthocyanidins found in red head cabbage with the content of 44.52 mg 100 g− 1 fresh weight (fw). Total isothiocyanates in flat head cabbage was significantly higher than other head cabbages. Red head cabbage had the significant the highest level of total phenolics and flavonoids with the values of 153.94 mg gallic acid equivalents·100 g− 1 and 51.32 mg rutin equivalents·100 g− 1, respectively, while flat head cabbage had the lowest level. Red head cabbage exhibited the highest antioxidant activity as measured by 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) and 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging and ferric ion reducing antioxidant power (FRAP) assays with the values of 69.82, 87.23% and 0.53, respectively. The study suggests that different varieties of head cabbages have different nutritional advantages, and provides useful information to recommend the right head cabbages for consumers.