A nutraceutical lesson from Brassica vegetables: cardioprotection by sulforaphane.

Cruciferous vegetables, of which the most commonly consumed come from the Brassica genus, are rich sources of sulfur-containing compounds called glucosinolates; their hydrolysis by a class of plant enzymes called myrosinases results in the formation of biologically active compounds, such as indoles and isothiocyanates. Myrosinase transforms glucoraphanin, a glucosinolate from which the enzyme is physically separated in intact plant cells, into the isothiocyanate sulforaphane (SF) upon damage to the plant such as from chopping or chewing. SF demonstrated a strong chemopreventive effect both in vitro and in vivo and one of the possible mechanism is thought to be related to the induction of phase 2 enzymes of xenobiotic transformation. Most of these enzymes have antioxidant properties as they detoxify reactive electrophiles, oxidised compound, etc. Thus, SF could be considered to act as an indirect antioxidant because it boosts the antioxidant defence system capacity. The up-regulation of endogenous antioxidant systems may represent a promising strategy for protecting cells against oxidative damage. No data are available to support a similar role of SF in cardioprotection. In this study, using primary cultures of neonatal rat cardiomyocytes, we examined if SF treatment can induce phase 2 enzymes and if this role of chemical inducer can lead to cardioprotection against oxidative stress. In particular, we have characterized the time dependent SF effect on gene expression, induction, and activity of a series of endogenous antioxidants and phase 2 enzymes. We have also investigated the protective effects of the SF-induced cellular defences on cardiac cell injury elicited by H2O2.