ScreeningBrassicaspecies for glucosinolate content

Abstract

Glucosinolates (GSLs), a group of compounds found in Brassica plants, are toxic to some soil-borne plant pathogens because of the toxicity of their hydrolysis products, isothiocyanates. Other phytochemicals found in Brassica plants, such as phenols and ascorbic acid, may compliment the activity of GSLs. A survey of Brassica accessions from the national germplasm repository was conducted to identify potential cover crops that could be soil-incorporated for use as biofumigants. Ten Brassica accessions that demonstrated relative cold tolerance, rapid maturity, and superior biomass production were selected. The selected accessions were grown under three climatic conditions (fall greenhouse, winter high tunnel, and spring field) to investigate whether growing conditions affect their GSL, phenol, and ascorbic acid content. The selected accessions included seven accessions of Brassica juncea (Indian mustard), one of Brassica napus (oil seed rape), one of Brassica campestris (field mustard), and one of Eruca sativa (arugula). Separation of GSLs from the selected Brassica accessions was achieved using ion-exchange sephadex in disposable pipette tips. Quantification of total GSLs was based on inactivation of the endogenous thioglucosidase and liberation of the glucose moiety from the GSL molecule by addition of standardized thioglucosidase (myrosinase) and colorimetry. GSL concentration of greenhouse, high tunnel, and field-grown shoots (leaves and stems) averaged 24, 40 and 76 micromoles g(-1) fresh weight, respectively. Accessions of B. juncea generally had the highest GSL content. A comparison of accessions revealed that Ames 8887 of B. juncea contained the greatest GSL concentration, but had the lowest biomass yield and ascorbic acid concentration, in part because phytochemical concentration tended to be negatively correlated with biomass yield. More promising was B. juncea accession 'Pacific Gold' which coupled high biomass yield with above-average GSL production, but had low phenol and ascorbic acid concentration. We concluded that environmental stress on growing plants can increase the concentration of GSLs, ascorbic acid, and total phenols in Brassica shoots, but does not increase yields of these phytochemicals per unit area.

Glucosinolates in collard greens grown under three soil management practices

“…Ascorbic acid concentration was positively correlated with the concentration of GSLs and phenols. [29] Plant phenols are among the factors that improve the efficacy of biofumigants for soil disinfestation. In addition, phenols have a strong antimicrobial effect against Phytophthora capsici (Phytophthora blight).…”

“…A fraction of the water extract that contained the hydrolysis products of the GSLs was subjected to a glucose determination procedure. [29] Collard extracts without the addition of purified horseradish myrosinase were used as controls. GSLs quantification in collard tissues was based on measurement of enzymatically released glucose.…”

“…Total GSLs were separated from the crude collard extracts by adsorption on DEAE-Sephadex A-25 (2-[diethylamino] ethyl ether) ion exchange resin of 40-125 mm bead size as described by Antonious et al [29,30] Five mL of the purified plant extracts were applied to disposable pipette tips (10 £ 1.2 cm) containing a small glass wool plugs (Fig. 1), ionexchange Sephadex (pre-swelled overnight with 2 M ammonium acetate) to give a settled resin height of 5 cm, and the resin was washed twice with 10 mL of deionized water.…”

“…The present study is a continuation of our previous work on the GSL content of Brassica, natural products for pest control, GSLs in greenhouse and tunnel grown Brassica plants, [29,30] and the impact of the growing environment on the internal composition of vegetables. [31] The objectives of this investigation were to: (1) assess variation in GSLs concentration among collard plants grown under three soil management practices: sewage sludge (SS) mixed with native soil, chicken manure (CM) mixed with native soil, and no-mulch (NM) native soil, (2) quantify GSLs concentrations in collard roots, leaves, and stems at harvest for potential use of their crude extracts in plant protection, and (3) assess myrosinase activity in soil amended with CM and SS compared to no-mulch native soil.…”

Food Intolerance: Associations with the rs12212067 Polymorphism of FOXO3 in Crohn's Disease Patients in New Zealand

“…This characteristic could also extend to two others on this list of adverse foods, mustard and wasabi. These food plants are members of the Brassicaceae family, which contain some quite distinctive phytochemicals, especially glucosinolates, which are not found in other plant families [37]. This assumes that the mustard under consideration is Indian mustard, Brassica juncea , the most commonly used type of mustard in commercial pastes.…”