Use of Crucifers containing the glucosinolate-myrosinase system as a source of bioactive molecules

摘要

Over the last decade, the demand for sustainable, nonpolluting agricultural techniques able to provide healthful and safe products for the end user has notably increased. These features are in line with the new international regulations that require a progressive reduction of synthetic chemicals use in agriculture and in food technology. In addition, many natural molecules,including those obtained by biotransformation, were found mild, safe and reliable remedies to prevent or to fight a number of human diseases. In this context, the use of less dangerous procedures and chemicals are expected to become more and more important in the near future. The beneficial effects of Brassicaceae use appears to be tightly associated with the content of myrosinase (MYR)-glucosinolate (GLs) system common in this plant family. This enzymatic system is important not only because it is one of the most significart protection structure in the plant kingdom, but also because it provides chemoprotection when assimilated with diet or useful outcomes in crop protection, particularly in biofumigation. Biofumigation using cruciferous-derived materials appears to be a sound alternative technology for improving human health by reducing environmental problems. As a matter of fact, there has recently been an increasing interest for natural compounds with high biocidal activities as possible substitute for methyl bromide and other synthetic fungicides. Although GLs are contained in all tissues of Brassicaceae, the seed is the preferential accumulation site. Environmental factors, plant species and age affect the GLs content and profile in Brassica seeds and tissues. Usually, intact GLs show low biological activity and chemical reactivity, while they are precursors of a number of bioactive molecules, and can break down by chemical, physical or enzymatic agents. All these reactions give rise to a number of different products depending on the type of degradation and reaction conditions, including isothiocyanates (ITCs). The latter are efficiently produced by the myrosinase-catalyzed hydrolysis of GLs and are valuable bioactive molecules that can be indirectly used in fine chemistry, food technology and crop protection. At present, the potential of GLs is mostly exploited using Brassica tissues (sprouts, flowering plants, dry plant tissues and seed meals). However, suitable formulates with higher biological activity that would allow a wider number of agricultural applications, are possible using pure components or concentrated extracts of the GLs-MYR system. GLs extracts can be economically produced should the current seed crushing and extraction plants be slightly modified to accommodate the biorefining technology that enhances their fractionation.