Glucosinolate accumulation in three important radish (Raphanus sativus) cultivars

Radish, Raphanus sativus, is an important dietary vegetable in Asian countries, especially in China, Japan, and Korea. In this study, the variation of glucosinolate (GSL) contents among three radish cultivars, including Seo Ho, Man Tang Hong, and Hong Feng No. 1 were evaluated. While significantly different levels of 13 GSLs were observed in both the skin and flesh of these radish cultivars, the levels in the skin, in general, were higher than those in the flesh. Among these 13 GSLs, glucoraphanin, glucobrassicin, methoxyglucobrassicin, and glucoraphasatin were present in both the skin and flesh of all 3 cultivars studied. Particularly, a large amount of glucoraphasatin was detected in the skin of all cultivars. Glucoraphenin was dominant in the flesh of Man Tang Hong, as well as in the skin of Hong Feng No. 1. Moreover, the skin of Man Tang Hong contained the highest level of glucobrassicin, which was 5.1, 4.6, and 4.5 times higher than the level in the flesh of Man Tang Hong, Hong Feng No. 1, and Seo Ho, respectively. In addition, the variation among the glucobrassicin levels in the skin of 3 cultivars was smaller than that among their flesh. Furthermore, neoglucobrassicin was present only in the skin of Seo Ho. Our results suggest that colorful radish (skin and flesh) cultivars might play a vital role for getting health benefit glucosinolate through consumption as vegetables.