Article

Radish sprouts versus broccoli sprouts: A comparison of anti-cancer potential based on glucosinolate breakdown products

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Abstract

Radish sprouts and broccoli sprouts have been implicated in having a potential chemoprotective effect against certain types of cancer. Each contains a glucosinolate that can be broken down to an isothiocyanate capable of inducing chemoprotective factors known as phase 2 enzymes. In the case of broccoli, the glucosinolate, glucoraphanin, is converted to an isothiocyanate, sulforaphane, while in radish a similar glucosinolate, glucoraphenin, is broken down to form the isothiocyanate, sulforaphene. When sprouts are consumed fresh (uncooked), however, the principal degradation product of broccoli is not the isothiocyanate sulforaphane, but a nitrile, a compound with little anti-cancer potential. By contrast, radish sprouts produce largely the anti-cancer isothiocyanate, sulforaphene. The reason for this difference is likely to be due to the presence in broccoli (and absence in radish) of the enzyme cofactor, epithiospecifier protein (ESP). In vitro induction of the phase 2 enzyme, quinone reductase (QR), was significantly greater for radish sprouts than broccoli sprouts when extracts were self-hydrolysed. By contrast, boiled radish sprout extracts (deactivating ESP) to which myrosinase was subsequently added, induced similar QR activity to broccoli sprouts. The implication is that radish sprouts have potentially greater chemoprotective action against carcinogens than broccoli sprouts when hydrolysed under conditions similar to that during human consumption.

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... Unlike in broccoli, breakdown of glucoraphenin (GRE), the GSL corresponding to GRA in broccoli, results in the production of SFE, rather than SFE nitrile, in radish plant. This process occurs because radish seeds and sprouts lack the epithiospecifier protein (ESP), which promotes nitrile formation during the breakdown of GSLs by myrosinase [18]. The anticancer properties of SFA from broccoli have been well documented, but research on the potential biological activities of SFE from radish is limited to a few recent studies. ...
... Compared with broccoli, kale, and other cruciferous vegetables, the radish is a better source of the ITC SFE because it lacks ESP, which inhibits the formation of ITCs. When fresh broccoli containing active ESP is consumed, the major hydrolysis product of GRA is predominantly SFA nitrile, which is an inactive form of SFA[18]. The ...
Preprint
Sulforaphene (SFE), a major isothiocyanate in radish seeds, is a close chemical relative of sulforaphane (SFA) isolated from broccoli seeds and florets. The anti-proliferative mechanisms of SFA against cancer cells have been well investigated, but little is known about the potential anti-proliferative effects of SFE. In this study, we showed that SFE purified from radish seeds inhibited the growth of six cancer cell lines (A549, CHO, HeLa, Hepa1c1c7, HT-29, and LnCaP), with relative half maximal inhibitory concentration (IC50) values ranging from 1.37 to 3.31 g/mL. Among the six cancer cell lines evaluated, SFE showed the greatest growth inhibition against A549 lung cancer cells. In A549 cells, SFE induced apoptosis via changes in the levels of poly (adenosine diphosphate ribose) polymerase and caspase-3, -8, and -9. Our results indicate that SFE from radish seeds may have significant anti-proliferative potency against a broad range of human cancer cells via induction of apoptosis.
... botrytis), and radish (Raphanus sativus), is associated with a decreasing risk of developing many cancers and cardiovascular diseases (Higdon, Delage, Williams, & Dashwood, 2007;Joseph et al., 2004;Lam et al., 2010;Truong, Baron-Dubourdieu, Rougier, & Guenel, 2010). This chemoprotective effect is related to isothiocyanates, a type of hydrolysis products of glucosinolates, which are relatively unique into cruciferous vegetables (Beevi, Mangamoori, Subathra, & Edula, 2010;Force, O'Hare, Wong, & Irving, 2007;O'Hare et al., 2009;Williams, Critchley, Pun, Chaliha, & O'Hare, 2010). When cruciferous vegetables are ground or chopped, glucosinolates are hydrolyzed by myrosinase enzyme (b-thioglucoside glucohydrolase, EC3.2.3.1) to a variety of biological products such as isothiocyanates, thiocyanates, nitriles, oxazolidine-thiones and epithionitriles (Bones & Rossiter, 2006;Vaughn & Berhow, 2005). ...
... Radish sprouts have been shown to be capable of inducing the phase II enzyme, quinone reductase, in vitro in murine hepatoma cell line O'Hare et al., 2009), and activating the antioxidant response element in a stably transfected hepatoma cell line (Hanlon & Barnes, 2011). These biological activities have been remarkably attributed to the radish sprouts' glucosinolate composition. ...
Article
Glucosinolates are sulphur-containing glycosides found in brassicaceous plants that can be hydrolysed enzymatically by plant myrosinase or non-enzymatically to form primarily isothiocyanates and/or simple nitriles. From a human health perspective, isothiocyanates are quite important because they are major inducers of carcinogen-detoxifying enzymes. Two of the most potent inducers are benzyl isothiocyanate (BITC) present in garden cress (Lepidium sativum), and phenylethyl isothiocyanate (PEITC) present in watercress (Nasturtium officinale). Previous studies on these salad crops have indicated that significant amounts of simple nitriles are produced at the expense of the isothiocyanates. These studies also suggested that nitrile formation may occur by different pathways: (1) under the control of specifier protein in garden cress and (2) by an unspecified, non-enzymatic path in watercress. In an effort to understand more about the mechanisms involved in simple nitrile formation in these species, we analysed their seeds for specifier protein and myrosinase activities, endogenous iron content and glucosinolate degradation products after addition of different iron species, specific chelators and various heat treatments. We confirmed that simple nitrile formation was predominantly under specifier protein control (thiocyanate-forming protein) in garden cress seeds. Limited thermal degradation of the major glucosinolate, glucotropaeolin (benzyl glucosinolate), occurred when seed material was heated to >120 degrees C. In the watercress seeds, however, we show for the first time that gluconasturtiin (phenylethyl glucosinolate) undergoes a non-enzymatic, iron-dependent degradation to a simple nitrile. On heating the seeds to 120 degrees C or greater, thermal degradation of this heat-labile glucosinolate increased simple nitrile levels many fold.
Article
The chemical nature of the hydrolysis products from the glucosinolate-myrosinase system depends on the presence or absence of supplementary proteins, such as epithiospecifier proteins (ESPs). ESPs (non-catalytic cofactors of myrosinase) promote the formation of epithionitriles from terminal alkenyl glucosinolates and as recent evidence suggests, simple nitriles at the expense of isothiocyanates. The ratio of ESP activity to myrosinase activity is crucial in determining the proportion of these nitriles produced on hydrolysis. Sulphoraphane, a major isothiocyanate produced in broccoli seedlings, has been found to be a potent inducer of phase 2 detoxification enzymes. However, ESP may also support the formation of the non-inductive sulphoraphane nitrile. Our objective was to monitor changes in ESP activity during the development of broccoli seedlings and link these activity changes with myrosinase activity, the level of terminal alkenyl glucosinolates and sulphoraphane nitrile formed. Here, for the first time, we show ESP activity increases up to day 2 after germination before decreasing again to seed activity levels at day 5. These activity changes paralleled changes in myrosinase activity and terminal alkenyl glucosinolate content. There is a significant relationship between ESP activity and the formation of sulforaphane nitrile in broccoli seedlings. The significance of these findings for the health benefits conferred by eating broccoli seedlings is briefly discussed.
Article
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Article
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Article
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Article
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Article
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