Relationship between conversion rate of glucosinolates to isothiocyanates/indoles and genotoxicity of individual parts of Brassica vegetables

Abstract

The studies on the characterisation of glucosinolates (GLs) and their breakdown products in Brassicaceae species focus mainly on the edible parts. However, other products, e.g., dietary supplements, may be produced also from non-edible parts such as roots or early forms of growth: seeds or sprouts. Biological activity of these products depends on quantitative and qualitative GL composition, but is also strictly determined by GL conversion rate to chemopreventive isothiocyanates (ITC) and indoles. The aim of this study was to evaluate the conversion rate of GLs to ITC and indoles for various plant parts of chosen Brassica species in relation to their biological activity. For this purpose, the composition of GLs and their degradation products was determined as well as activity of myrosinase. Toxicological part of studies involved: MTT assay, restriction analysis, comet assay and Ames test. The composition of GLs and conversion rate to ITC and indoles was found to differ significantly between Brassica species and individual parts of the plant. The highest efficiency of conversion was observed for edible parts of plants: more than 70%, while in sprouts, it reached less than 1%, though myrosinase activity did not differ. The conversion rate directly affected biological activity of plant material. Higher concentration of ITC/indoles in the sample led to the increase of cytotoxicity. Majority of tested samples were able to induce covalent DNA modification in cell-free system. It was also confirmed that the presence of indolic GLs and products of their degradation stimulated mutagenicity, but did not lead to DNA fragmentation in cultured cells.

Cytotoxicity of Selenium-Enriched Chinese Kale (Brassica oleracea var. alboglabra L.) Seedlings Against Caco-2, MCF-7 and HepG2 Cancer Cells

“…gemmifera) had 0.37 ± 0.02 µmol/g DW and radish (Raphanus sativus var. sativus) had the highest 9.67 ± 0.03 µmol/g DW 19 which were all lower than the total ITC content found in our broccoli microgreens and Se-KS suggesting that total ITC content varied amongst Cruciferous plant microgreens. The total ITC content was a correlation to the total glucosinolates present in these plants and once they were crushed, endogenous plant myrosinase was released to hydrolyze glucosinolates to ITCs.…”

Profiling of Individual Desulfo-Glucosinolate Content in Cabbage Head (Brassica oleracea var. capitata) Germplasm

“…After analyzing the individual GSLs and their content, some of the genotypes were selected based on the targeted GSLs (Table 3). Specifically, genotypes with the highest GBS, IBE, GRA and SIN content may have a potential for health benefits, as the hydrolysis product of these GSLs show anticancer properties [7,9,28,46,49]. PCA for individual GSLs showed that some selected genotypes had higher specific GSL content (Table 3 and Figure 4).…”

“…It is highly nutritious and possess a wide range of health-promoting bioactive compounds such as GSLs, vitamins, phenols, anthocyanin and carotenoids [12,[20][21][22][23][24][25]. The profile and content of given bioactive compounds varies due to genetic and environmental factors such as growth seasons and conditions and developmental stages [20][21][22]24,[26][27][28]. GSL profile and their content have been studied in several Brassica vegetables: broccoli [29], radish [30], Chinese cabbage [31], rape [32], turnip [33,34] and pakchoi [35].…”

Inactivation of Thioglucosidase from Sinapis alba (White Mustard) Seed by Metal Salts

“…This latter compound is spontaneously converted into isothiocyanates, nitriles, thiocyanates, epithionitriles, indoles, or 1,3-oxazolidine-2-thiones. The type of glucosinolate product obtained during hydrolysis strictly depends on the reaction conditions and the original glucosinolate side-chain structure (aliphatic, aromatic, and indolic) [ 9 , 10 ].…”