Glucosinolate composition and anti-cancer potential of seed-sprouts from horticultural members of the brassicaceae

Abstract

Glucosinolates, or more specifically their isothiocyanate breakdown products, have been identified as having anti-cancer potential via their ability to induce phase 2 detoxification enzymes in humans. In particular, glucoraphanin (which degrades to form sulphoraphane) has received considerable interest owing to its high potency and presence in broccoli, a well known vegetable in Western society. There are however many other vegetables available containing glucosinolates of varying potency. Interestingly, consumption of a vegetable containing a glucosinolate with half the potency of glucoraphanin has similar impact on phase 2 enzyme induction, if twice the amount is consumed. In the case of sprouted-seed, which tend to be higher in glucosinolate concentration than mature vegetables, this does not represent a big difference in the amount ingested, and is good news for a consumer who does not like the taste of broccoli. We analysed the glucosinolate composition of sprouted-seed of a wide range of ‘Asian’ and ‘Western’ vegetables belonging to the Brassica family. Using published phase 2 enzyme induction values for isothiocyanate derivatives, we were able to rate the anti-cancer potential for different sprouts in comparison to Broccoli. Vegetables that performed well included radish, kohl rabi and daikon, and to a lesser extent kale, rocket, Chinese broccoli, cabbage and garden cress.