Glucosinolates in Chinese Brassica campestris Vegetables: Chinese Cabbage, Purple Cai-tai, Choysum, Pakchoi, and Turnip

Abstract

Brassica campestris vegetables play an important role in the Chinese diet. The objective of this study was to evaluate the composition and content of glucosinolates (GSs) in five species of Chinese Brassica campestris vegetables by high-performance liquid chromatography. The compositions and contents of GSs varied significantly among and within species and cultivars. The contents of total GSs were 100 to 130 mg/100 g fresh weight (FW) in turnip (B. rapifera), 50 to 70 mg/100 g FW in purple cai-tai (B. chinensis var. purpurea), and 14 to 35 mg/100 g FW in Chinese cabbage (B. pekinensis), choysum (B. chinensis var. utilis), and pakchoi (B. chinensis var. communis). In Chinese cabbage, the predominant individual GSs were glucobrassicin for both cultivars, neoglucobrassicin only for ‘zaoshuwuhao’, and gluconapin only for ‘zaoshuwuhao’. The predominant individual GSs were glucobrassicanapin and gluconapin in purple cai-tai and choysum and gluconapin in pakchoi and turnip. The relative content of total aliphatic GSs was 80% to 90% in purple cai-tai and choysum, 60% to 65% in pakchoi and turnip, and 17% to 50% in Chinese cabbage. The relative content of total indolic GSs was 37% to 75% in Chinese cabbage, 25% to 27% in pakchoi, and 5% to 17% in purple caitai, choysum, and turnip. The relative content of aromatic GSs was 28% to 36% in turnip, 8% to 14% in Chinese cabbage and pakchoi, and 2% to 4% in choysum and purple cai-tai. These results suggest that there are significant genotypic variations in composition and content of glucosinolates in Chinese Brassica campestris vegetables.