Direct Antioxidant Activity of Purified Glucoerucin, the Dietary Secondary Metabolite Contained in Rocket (Eruca sativa Mill.) Seeds and Sprouts
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- 作者：Jessica Barillari ; Donatella Canistro ; Moreno Paolini ; Fiammetta Ferroni ; Gian Franco Pedulli ; Renato Iori ; and Luca Valgimigli
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2005
- 出版时间：April 6, 2005
- 年：2005
- 卷：53
- 期：7
- 页码：2475 - 2482
- 全文大小：99K
- 年卷期：v.53,no.7(April 6, 2005)
- ISSN：1520-5118
文摘
Rocket (Eruca sativa Mill. or Eruca vesicaria L.) is widely distributed all over the world and is usuallyconsumed fresh (leafs or sprouts) for its typical spicy taste. Nevertheless, it is mentioned in traditionalpharmacopoeia and ancient literature for several therapeutic properties, and it does contain a numberof health promoting agents including carotenoids, vitamin C, fibers, flavonoids, and glucosinolates(GLs). The latter phytochemicals have recently gained attention as being the precursors ofisothiocyanates (ITCs), which are released by myrosinase hydrolysis during cutting, chewing, orprocessing of the vegetable. ITCs are recognized as potent inducers of phase II enzymes (e.g.,glutathione transferases, NAD(P)H:quinone reductase, epoxide hydrolase, etc.), which are importantin the detoxification of electrophiles and protection against oxidative stress. The major GL found inrocket seeds is glucoerucin, GER (108 ± 5 
mol g-1 d.w.) that represents 95% of total GLs. Thecontent is largely conserved in sprouts (79% of total GLs), and GER is still present to some extentin adult leaves. Unlike other GLs (e.g., glucoraphanin, the bio-precursor of sulforaphane), GERpossesses good direct as well as indirect antioxidant activity. GER (and its metabolite erucin, ERN)effectively decomposes hydrogen peroxide and alkyl hydroperoxides with second-order rate constantsof k2 = 6.9 ± 0.1 × 10-2 M-1 s-1 and 4.5 ± 0.2 × 10-3 M-1 s-, respectively, in water at 37 
C,thereby acting as a peroxide-scavenging preventive antioxidant. Interestingly, upon removal of H2O2or hydroperoxides, ERN is converted into sulforaphane, the most effective inducer of phase II enzymesamong ITCs. On the other hand, ERN (and conceivably GER), like other ITCs, does not possessany chain-breaking antioxidant activity, being unable to protect styrene from its thermally (37 C)initiated autoxidation in the presence of AMVN. The mechanism and relevance of the antioxidantactivity of GER and ERN are discussed.Keywords: Antioxidant; rocket; Eruca sativa (Mill.); Eruca vesicaria (L.); glucosinolate; isothiocyanate;glucoerucin; erucin
mol g-1 d.w.) that represents 95% of total GLs. Thecontent is largely conserved in sprouts (79% of total GLs), and GER is still present to some extentin adult leaves. Unlike other GLs (e.g., glucoraphanin, the bio-precursor of sulforaphane), GERpossesses good direct as well as indirect antioxidant activity. GER (and its metabolite erucin, ERN)effectively decomposes hydrogen peroxide and alkyl hydroperoxides with second-order rate constantsof k2 = 6.9 ± 0.1 × 10-2 M-1 s-1 and 4.5 ± 0.2 × 10-3 M-1 s-, respectively, in water at 37 C,thereby acting as a peroxide-scavenging preventive antioxidant. Interestingly, upon removal of H2O2or hydroperoxides, ERN is converted into sulforaphane, the most effective inducer of phase II enzymesamong ITCs. On the other hand, ERN (and conceivably GER), like other ITCs, does not possessany chain-breaking antioxidant activity, being unable to protect styrene from its thermally (37 C)initiated autoxidation in the presence of AMVN. The mechanism and relevance of the antioxidantactivity of GER and ERN are discussed.Keywords: Antioxidant; rocket; Eruca sativa (Mill.); Eruca vesicaria (L.); glucosinolate; isothiocyanate;glucoerucin; erucin