Glucosinolates in Crucifer Vegetables: Broccoli, Brussels Sprouts, Cauliflower, Collards, Kale, Mustard Greens, and Kohlrabi

Correlation coefficients based on relative concentrations of 13 glucosinolates in the edible parts of 30 culth'ars were determined. Brussels sprouts (Brassica oleracea L. gemmifera group), cauliOower (8. oleracea L. botlJ·tis group), and either marrow-stem or smooth-leafed kale (B, oleracea L. aceplzala group) had similar glucosinolate patterns based on significant correlations (P < 0.01). The glucosinolates of 'Morris Heading' collards [(8. oleracea L. aceplzala group (var. sabellica)] were highly correlated with those of curl)' kale [B. oleracea L. aceplzala group (var. selensia)]. Mustard greens [B. jUllcea (L.) Czern. & Cass. var. rugosa Baile,Y] and the corresponding seeds 'vere the most highly correlated of the 17 cuItivars for which the edible parts and seeds were compared. Seed analyses indicated relationships among the cuJti"ars somewhat similar to those seen for the edible portions. Crucifer vegetables play an important role in the American diet. In 1983, the United States produced 352,000 t of fresh broccoli (Brassica oleracea L. itafica group), and 259,000 t of fresh cauliflower (36). However, the naturally occurring glu, cosinolates (GSs) in the edible crucifers should be monitored because of their potenlial detrimental or beneficial effects on health. The tendency to produce goiter has been shown for cau, liflower (2,24), kale (3), kohlrabi (B. oleracea L. gOllgylodes group) (2), and brussels sprouts (24). As illustrated in Figs. I and 2, isothiocyanates (NCSs), oxazolidine,2,thiones (OZTs), and thiocyanate (SCN) ion are liberated from GSs by the action of the enzyme thioglucoside glucohydrolase [EC 3.2.3.1] (34). The biological activity of these GS breakdown producls has been studied. Thiocyanale ion from 3,indolylmethyl,GSs (Table I) is known to inhibit the accumulation of iodide in the Ihyroid gland (37) and may be a predisposing faclor for goiter. Increased liver and thyroid weights in rats have been linked wilh 5,vinyl, OZT (27), a compound produced from 2,hydroxy,3,butenyl,GS (Fig. 2). On the other hand, the GS hydrolysis products benzyl, Receivcd for publicalion 15 Oct. 1985. The mention of liml names or trade producls does nOI imply Ihat they are endorsed or rccommendcd by the U.S. Departlllcnt of Agriculture over othcr fions or similar products not mentioned. Wc thank G.B. Rosc and W.l. Bailey for technical assistance and G.F. Spenccr and R.D. Plattner for GC-MS idcnlification. Thc cost of publishing Ihis papcr was defrayed in part by the payment of page charges. Under postal regulations. this paper therefore must be hereby marked (/{h'erlist'lI/('lIl solely to indicate this fact.