Assessing the anticancer compounds Se-methylselenocysteine and glucosinolates in Se-biofortified broccoli (brassica oleracea L. var. italica) sprouts and florets

Authors: AVILA, FABRICIO - Cornell University; FAQUIN, VALDEMAR - University Of Lavras(UNILAVRAS); Yang, Yong; RAMOS, SILVIO - University Of Lavras(UNILAVRAS); GUILHERME, LUIZ - University Of Lavras(UNILAVRAS); Thannhauser, Theodore - Ted; Li, Li

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/13/2013
Publication Date: 7/3/2013
Citation: Avila, F., Faquin, V., Yang, Y., Ramos, S., Guilherme, L., Thannhauser, T.W., Li, L. 2013. Assessing the anticancer compounds Se-methylselenocysteine and glucosinolates in Se-biofortified broccoli (brassica oleracea L. var. italica) sprouts and florets. Journal of Agricultural and Food Chemistry. 61:6216-6223.

Interpretive Summary: Foods fortified with selenium have been advocated as functional foods. Broccoli is selenium secondary accumulator that also contains large amount of chemopreventive glucosinolates. In this study, we evaluated and compared the effect of selenium treatment on the accumulation of Se-methylselenocysteine and glucosinolates in broccoli sprouts and florets, the two groups of anticancer compounds in two edible tissues. We found that while selenate is better form to induce Se-methylselenocysteine formation in florets, both selenate and selenite are equally effective in promoting Se-methylselenocysteine synthesis in sprouts. Distinctive glucosinolate profiles were observed between broccoli sprouts and florets, and sprouts contain dominantly glucoraphanin, the potent anticancer precursor. While sprouts can simatenously enhance both Se-methylselenocysteine and glucosinolate compounds, antagonistic relationship between Se-methylselenocysteine and glucosinolate accumulation was observed in florets. Thus, Se-biofortified broccoli sprouts are an excellent source of multiple chemopreventive compounds.

Technical Abstract: Broccoli (Brassica oleracea L. var. italica) is a rich source of chemopreventive compounds. Here, we evaluated and compared the effect of selenium (Se) treatment on the accumulation of anticancer compound Se-methylselenocysteine (SeMSCys) and glucosinolates in broccoli sprouts and florets. Total Se and SeMSCys content in sprouts increased concomitantly with increasing Se doses. Selenate was superior to selenite in inducing total Se accumulation, but selenite is equally effective as selenate in promoting SeMSCys synthesis in sprouts. Increasing sulfur doses reduced total Se and SeMSCys content in sprouts treated with selenate, but not with selenite. Examination of five broccoli cultivars reveals that sprouts generally have better fractional ability than florets to convert inorganic Se into SeMSCys. Distinctive glucosinolate profiles between sprouts and florets were observed, and sprouts contained approximately 6-fold more glucoraphanin than florets. In contrast to florets, glucosinolate content was not affected by Se treatment in sprouts. Thus, Se-enriched broccoli sprouts are excellent for simultaneous accumulation of chemopreventive compound SeMSCys and glucoraphanin.