Glucosinolate Profiles in Cabbage (Brassica oleracea var. capitata) Cultivars and Their Effect on the Induction of a Phase II Detoxification Enzyme

Abstract

This study presents a profile of glucosinolate (GSL) levels in the edible portions of 31 cultivars of cabbage cultivated in Japan, and compares potential bioactivity levels on the basis of their ability to induce quinone reductase (QR), a phase II detoxification enzyme. Cabbage (Brassica oleracea var. capitata) seeds were sown in early March 2005 (summer-harvest) and early August 2005 (winter-harvest) and grown under uniform culture conditions. Total GSL concentration varied from 1.07 to 12.14 (mean 5.73) µmol·gDW −1 in the summer-harvest, and from 3.42 to 10.26 (mean 6.16) µmol·gDW −1 in the winter-harvest. The most predominant GSL was 3-indolylmethyl glucosinolate, 2-propenyl glucosinolate or 2-hydroxy-3-butenyl glucosinolate, depending on the cultivar. The values of relative QR activity were positively correlated only with 4-methylsulfinylbutyl glucosinolate (glucoraphanin, GR) content in both the summer-harvest (r = 0.51) and winter-harvest (r = 0.77). GR concentration ranged from 0.04 to 1.70 (mean 0.43) µmol·gDW −1 in the summer-harvest, and from 0.11 to 1.39 (mean 0.44) µmol·gDW −1 in the winter-harvest. There was no significant correlation between GR content and total GSL in either the summer-harvest (r = 0.31) or winter-harvest (r = 0.24). Among the same cultivars, there was a significant positive correlation between GR content in the summer-harvest and that in the winter-harvest (r = 0.63). These results suggest that the inducing activity of QR increased with GR content independent of total GSL, and that there are some inherent differences between cabbage cultivars in the intensity of this activity.Key Words: cabbage, cultivar, glucosinolate, quinone reductase. IntroductionEpidemiological studies suggest that dietary cruciferous vegetables lower the risk for a number of cancers (Herr and Büchler, 2010). Cruciferous vegetables contain a group of secondary metabolites termed glucosinolates (GSLs), which are not present in other vegetables. Cruciferous vegetables also have myrosinase (β-thioglucosidase, EC 3.2.3.1), which is physically separate from its substrate, GSL, in intact plant tissues. Following tissue damage, during chopping and chewing of the vegetable, myrosinase comes into contact with the GSLs, which are then hydrolyzed to isothiocyanate and other products (Bones and Rossiter, 1996).The anticarcinogenic effects of cruciferous vegetables are considered to be related to GSL hydrolysis products (Zhang, 2004). Broccoli (Brassica oleracea var. italic) contains a high amount of 4-methylsulfinylbutyl glucosinolate (glucoraphanin, GR) (Kushad et al., 1999), a member of the GSL, which is enzymatically hydrolyzed by myrosinase, when plant tissues are disrupted, into the corresponding isothiocyanate, 4-methylsulfinylbutyl isothiocyanate (sulforaphane), and other breakdown products. Sulforaphane was initially identified as a potential anticarcinogen by its capacity to induce quinone reductase (QR), a phase II detoxification enzyme, in Hepa lclc7 cell culture (Zhang et al., 1992). To date, there has been ...

Isothiocyanates, Nitriles, and Epithionitriles from Glucosinolates Are Affected by Genotype and Developmental Stage in Brassica oleracea Varieties

“…Overall, in the present study, both developmental stages, namely sprouts and fully developed heads, of the white and savoy cabbage cultivars were dominated by 2Prop, 3MSOP, and I3M, reconfirming previous Brassica studies ( Ciska et al, 2000 ; Bellostas et al, 2007 ; Hirono et al, 2011 ). Generally, sprouts of the three red cabbage cultivars contained mainly 4MSOB, but also had considerable levels of 2Prop, (R)2OH3But, and 3MSOP.…”

Distribution of Indolic Glucosinolates in Different Developmental Stages and Tissues of 13 Varieties of Cabbage (Brassica oleracea L. var. capitata)

“…This study compared the differences among the four GLS between the high-GLS material (M18-15) and the low-GLS material (LQ66) (Figure 8). In the tested cabbage varieties, the I3M of the middle and inner leaves was higher than the other three GLS, supporting that the leaves of cabbage at maturity are rich in I3M like in previous reports [40,50]. In contrast, this study also found that in most cabbage varieties, the content of 4OH-I3M was significantly higher than that of the other three GLS (Figure 8D), representing the difference of GLS enrichment in different organs of GLS.…”