The major aliphatic glucosinolate content in Korean radish during vegetative and reproductive growth

Abstract

Glucosinolates (GSLs) are secondary metabolites abundant in Brassica vegetables and the interest on this compound has been grown due to their health benefits. The amounts of major aliphatic GSLs, glucoraphasatin (GRH), and glucoraphenin (GRE) were measured in five radish cultivars during their vegetative and reproductive growth. The GRE content was higher in seed (ranging from 16.5 to 19.4 mg·g−1 dry weight) than that of leaves or roots in all five genotypes. The GRE content sharply declined during germination and remained stable at the basal level for the subsequent vegetative growth period. In contrast, the amount of GRH, an immediate precursor of the GRE, steadily increased during the early growth period up to 8 weeks and remained at a similar level thereafter. As growth of seedlings progressed, the inner leaves contained higher amounts of GRH than the outer leaves. In roots, smaller amounts of GRE were found, as compared to other tissues. However, the GRH was abundant in roots and mature inner leaves. The GRE tended to accumulate in reproductive organs, while GRH was found primarily in the roots and the inner leaves at the mature stage.