High-performance liquid chromatographic method for separation and quantification of intact glucosinolates

The Yeast Fermentation Effect on Content of Bioactive, Nutritional and Anti-Nutritional Factors in Rapeseed Meal

The aim of this study was to evaluate the changes in the content of bioactive, nutritional and anti-nutritional factors in rapeseed meal that was fermented with Saccharomyces cerevisiae or Saccharomyces boulardii yeasts at two different periods of time, for improvement of nutritional characteristics in piglets’ feeding. The fermentation has reduced the content of two anti-nutritional factors, intact glucosinolates and 3-butyl isothiocyanate, by 51.60–66.04% and 55.21–63.39%, respectively, by fermentation with either Saccharomyces cerevisiae or Saccharomyces boulardii for 24 h. The fermentation by these yeasts also lowered the content of total polyphenolic compounds by 21.58–23.55% and antioxidant activity (DPPH) by 17.03–21.07%. Furthermore, the content of carbohydrates and organic acids has dramatically decreased between 89.20 and 98.35% and between 31.48 and 77.18%, respectively. However, the content of some individual phenolic acids (gallic, p-coumaric, sinapic) and crude protein content (10–13%) has been increased. Thus, the results showed that fermentation with Saccharomyces cerevisiae or Saccharomyces boulardii has reduced the content of antinutritive factors and increased the protein content of the rapeseed meal, without major adverse effects on its overall nutritive value.

A liquid chromatography-mass spectrometry approach to study "glucosinoloma" in broccoli sprouts

Glucosinolates are an important class of secondary plant metabolites, possessing health-promoting properties. Young broccoli plants are a very good source of glucosinolates with concentrations several times greater than in mature plants. The aim of our study was to develop a liquid chromatography-mass spectrometry and liquid chromatography/tandem mass spectrometry qualitative and quantitative method for the measure of glucosinolates in broccoli sprouts. The described method provides high sensitivity and specificity, allowing a rapid and simultaneous determination of 14 glucosinolates. The proposed method has been validated for eight glucosinolates: glucobrassicin, glucoraphanin, glucoiberin, glucoerucin, progoitrin, gluconapin, sinigrin and glucocheirolin. The linear range was 1-150 µg ml(-1), the intra-day and inter-day precision values are within 6% and 8% at the lower limit of quantification, while the overall recovery of the eight glucosinolates was 99 ± 9%. This validated method was used successfully for analysis of glucosinolates content of broccoli sprouts grown in different conditions.

Analysis of glucosinolates, isothiocyanates, and amine degradation products in vegetable extracts and blood plasma by LC–MS/MS

Dietary glucosinolates are under intensive investigation as precursors of cancer-preventive isothiocyanates. Quantitation of the dose and bioavailability of glucosinolates and isothiocyanates requires a comprehensive analysis of the major dietary glucosinolates, isothiocyanates, and related metabolites. We report a liquid chromatography with tandem mass spectrometric detection (LC-MS/MS) analytical method for the comprehensive analysis of the seven major dietary glucosinolates, related isothiocyanates, and putative amine degradation products. The parent glucosinolates were sinigrin, gluconapin, progoitrin, glucoiberin, glucoraphanin, glucoalyssin, and gluconasturtiin. The LC-MS/MS analysis method for these compounds was developed and validated; a standard addition analysis protocol was used generally to avoid the requirement for stable isotopic standards. Where stable isotopic standards were available, internal standardization with these gave estimates in agreement with those obtained by the standard addition analysis protocol. For glucosinolates, negative ion electrospray LC-MS/MS analysis was performed. Isothiocyanates and amines were prederivatized to the corresponding thiourea and N-acetamides, respectively, and were quantified by positive ion electrospray LC-MS/MS. The limits of detection were 0.5-2 pmol; the recoveries for glucosinolates, isothiocyanates, and amines were 85-90%, 50-85%, and 60-70%, respectively; and the intra- and interbatch coefficients of variation were 1-4% and 3-10%, respectively. These methods provide facile access to comprehensive analytical data on the major dietary glucosinolates and related metabolites to quantify inputs and metabolic formation of these compounds in cancer prevention and related studies.

High-performance liquid chromatographic separation of natural and synthetic desulphoglucosinolates and their chemical validation by UV, NMR and chemical ionisation-MS methods

Methods are described for the optimised extraction, desulphation and HPLC separation of desulphoglucosinolates. These methods provide rapid separation, identification and quantitative measurements of glucosinolates extracted from Brassica napus L and related crops, of unusual glucosinolates found in crucifer weed species, and also of synthetic alkylglucosinolates. The desulphoglucosinolates used in these studies were either chemically synthesised (at least one example from each major structural class), or purified from various plant sources. Validation of the identities of the desulphoglucosinolates was by comparison of retention times with standards, and by UV, 1H- and 13C-NMR and chemical ionisation MS analysis. A list of useful species, and the specific tissues, from which high concentrations of standards can be extracted is included.