Determination of conjugated and free isoflavones in some legumes by LC–MS/MS

Metabolites profiling, in-vitro and molecular docking studies of five legume seeds for Alzheimer's disease

Even though legumes are valuable medicinal plants with edible seeds that are extensively consumed worldwide, there is little information available on the metabolic variations between different dietary beans and their influence as potential anti-cholinesterase agents. High-resolution liquid chromatography coupled with mass spectrometry in positive and negative ionization modes combined with multivariate analysis were used to explore differences in the metabolic profiles of five commonly edible seeds, fava bean, black-eyed pea, kidney bean, red lentil, and chickpea. A total of 139 metabolites from various classes were identified including saponins, alkaloids, phenolic acids, iridoids, and terpenes. Chickpea showed the highest antioxidant and anti-cholinesterase effects, followed by kidney beans. Supervised and unsupervised chemometric analysis determined that species could be distinguished by their different discriminatory metabolites. The major metabolic pathways in legumes were also studied. Glycerophospholipid metabolism was the most significantly enriched KEGG pathway. Pearson's correlation analysis pinpointed 18 metabolites that were positively correlated with the anti-cholinesterase activity. Molecular docking of the biomarkers to the active sites of acetyl- and butyryl-cholinesterase enzymes revealed promising binding scores, validating the correlation results. The present study will add to the metabolomic analysis of legumes and their nutritional value and advocate their inclusion in anti-Alzheimer's formulations.

Chemical composition of kabuli and desi chickpea (Cicer arietinum L.) cultivars grown in Xinjiang, China

Chickpeas are a very important legume crop and have abundant protein, carbohydrate, lipid, fiber, isoflavone, and mineral contents. The chemical compositions of the four chickpea species (Muying-1, Keying-1, Desi-1, Desi-2) from Xinjiang, China, were analyzed, and 46 different flavonoids in Muying-1 were detected. The moisture content ranged from 7.64 ± 0.01 to 7.89 ± 0.02 g/100 g, the content of starch in the kabuli chickpeas was greater than that in the desi chickpeas, the total ash content ranged from 2.59 ± 0.05 to 2.69 ± 0.03 g/100 g and the vitamin B1 content of the chickpeas ranged from 0.31 to 0.36 mg/100 g. The lipid content ranged from 6.35 to 9.35 g/100 g and the major fatty acids of chickpeas were linoleic, oleic, and palmitic acids. Both kabuli and desi chickpeas have a high content of unsaturated fatty acids (USFAs), Muying-1 and Desi-1 contained the highest level of linoleic acid, and Keying-1 had the highest oleic acid content. The protein level ranged from 19.79 ± 2.89 to 23.38 ± 0.30 g/100 g, and the main amino acids were aspartic acid, glutamic acid, and arginine acid. The four chickpea species had significant amounts of essential amino acids (EAAs). Forty-six varieties of flavonoids in Muying-1 were determined by ultra high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-QqQ-MS) analysis, and there were higher levels of conjugate flavonoids (55.95%) than free flavonoids (44.05%). Isoflavones were the most abundant flavonoids in Muying-1, and among the isoflavones, daidzin had the highest content, followed by biochanin A and genistin. Muying-1 was rich in daidzin, biochanin A, genistin, troxerutin, isorhamnetin, astilbin, L-epicatechin, astragalin, acacetin, hyperoside, and myricitrin. Information provided in the study will be helpful to further understand the chemical composition of chickpeas and be beneficial to the development of chickpeas.

Revitalizing Unfermented Cabernet Sauvignon Pomace Using an Eco-Friendly, Two-Stage Countercurrent Process: Role of pH on the Extractability of Bioactive Phenolics

As the major byproduct of the winemaking industry, grape pomace remains an untapped source of valuable bioactive phenolic compounds. This study elucidated the optimal aqueous extraction parameters for maximizing phenolic extractability, while avoiding the use of harsh conventional solvents and limiting water usage, from Cabernet Sauvignon grape pomace in which the red grape was processed for white wine. In the single-stage aqueous extraction process (AEP), the concurrent impact of pH (2.64–9.36), solids-to-liquid ratio (SLR, g pomace/mL water) (1:50–1:5), and temperature (41.6–58.4 °C) on the total phenolic content (TPC) of Cabernet Sauvignon pomace was evaluated alongside a kinetic study (15–90 min). Optimal single-stage extraction conditions (pH 9.36, 1:50 SLR, 50 °C, 75 min) guided the development of a two-stage countercurrent extraction process (pH 9.36, 1:10 SLR, 50 °C, 75 min) to further reduce water consumption without compromising overall extractability. The countercurrent process reduced fresh water usage by 80%, increased the TPC of the extracts by 18%, and improved the in vitro antioxidant activities (ABTS and ORAC) of the extracts. Untargeted metabolomics enabled the identification of a diverse pool of phenolics, especially flavonol glycosides, associated with grape pomace, while further phenolic quantitation detected improvements in the release of commonly bound phenolics such as ferulic acid, p-coumaric acid, syringic acid, and protocatechuic acid in alkaline extracts compared to the ethanolic extract. This investigation provides an efficient, eco-friendly extraction strategy suitable for applications in functional food, beverage, nutraceutical, and cosmetic industries.

Mutivariate optimization strategy for the sonication-based extraction of Nardostachys jatamansi roots and analysis for chemical composition, anti-oxidant and acetylcholinesterase inhibitory potential

Extracts from medicinal plants are generally obtained by conventional methods like percolation and maceration. Owing to limitations of traditional methods and to meet the rising demand of extracts, the development of new green approaches is need of hour. In the present research, we have developed an ultrasound-assisted extraction (UAE) method for the Nardostachys jatamansi (NJ) D. Don, DC roots and optimized the extraction parameters for possible improved extract yield. A multivariate optimization strategy using the Centre Composite Design coupled with response surface methodology was applied. A numerical optimization approach accurately predicted the extraction conditions (sonication time ∼ 20 min, ethanol ∼ 70 % and a liquid/solid ratio of about 21:1). Scanning electron microscopy of the plant samples after UAE also indicated the cavitation effect due to sound waves. GC-MS analysis of the optimized ultrasound extract (OUNJ) confirmed improvement in the concentration of various secondary metabolites like jatamansone (91.8 % increase), spirojatamol (42.3 % increase), globulol (130.4 % increase), sitosterol (84.6 % increase) as compared to the soxhlet extract (SXNJ). Different anti-oxidant parameters (DPPH, Glutathione, Catalase SOD and NO) were also significantly altered (p < 0.05) in the optimized extracts. The IC₅₀ to inhibit acetylcholinesterase activity (AChE) in vitro and its concentration in brain homogenates were significantly (p < 0.05) improved by OUNJ extract as compared to the SXNJ ones. To conclude, we can say that established optimized conditions for UAE of N. jatamansi roots not only reduce the extraction time but also improved the pharmacological potential of the extracts.

Effects of enzyme-assisted extraction on the profile and bioaccessibility of isoflavones from soybean flour

The effects of enzymatic extraction strategies on extractability, bioconversion, and bioaccessibility of biologically active isoflavone aglycones, total phenolic content, and antioxidant activity of aqueous extracts from full-fat soy flour were evaluated. Protease, tannase, and cellulase enzymes were used individually or in combination. Except for the protease treatment, all enzymatic treatments increased the extraction of biologically active isoflavones (daidzein and genistein) compared with the control. The use of a mixture of protease, tannase, and cellulase resulted in increased extractability and/or bioconversion of aglycones from soy flour, indicating a synergistic effect amongst the enzymes. Daidzein and genistein concentrations increased from 29.0 to 158.2 μg/g and from 27.0 to 156.5 μg/g (compared to the control), respectively. Furthermore, enzymatic extraction followed by in vitro gastrointestinal digestion significantly increased the bioaccessibility of isoflavone aglycones, total phenolic content (by 22-45%), and antioxidant activity (by 15-22%) of the extracts. These results demonstrate that enzyme selection is an efficient strategy to maximize the extraction, bioconversion, and bioaccessibility of bioactive isoflavones from soy flour, which could contribute to health benefits associated with the consumption of soy-rich products.

Global Profiling and Structural Characterization of Metabolites of Ononin Using HPLC-ESI-IT-TOF-MSn After Oral Administration to Rats

Ononin is a bioactive isoflavone of legumes. To explore the "effective forms" of ononin, its metabolites were characterized using HPLC-ESI-IT-TOF-MSⁿ after oral administration to rats. Metabolites (106), including 94 new metabolites, were characterized, which contained 17 phase I, 23 hydroxylated and methylated, 54 sulfated, 10 glucuronidated, and 2 sulfated and glucuronidated metabolites. Six hydroxylated metabolites of formononetin (aglycone of ononin) were simultaneously detected for the first time. Twenty-three hydroxylated and methylated metabolites were the new metabolites of ononin, and the number of hydroxylation and methylation was 1-3 and 1-2. Twenty metabolites have ononin-related bioactivities, and many metabolites have the same bioactivities. Their probable mechanisms of action may be additive and/or synergistic effects, especially because of the addition of the blood concentrations of these compounds. The results provide a foundation for a better understanding of the "effective forms" of ononin.

Phytochemicals in Legumes: A Qualitative Reviewed Analysis

Legumes are an excellent source of nutrients and phytochemicals. They have been recognized for their contributions to health, sustainability, and the economy. Although legumes comprise several species and varieties, little is known about the differences in their phytochemical composition and the magnitude of these. Therefore, the aim of this review is to describe and compare the qualitative profile of phytochemicals contained in legumes and identified through LC-MS and GC-MS methods. Among the 478 phytochemicals reported in 52 varieties of legumes, phenolic compounds were by far the most frequently described (n = 405, 85%). Metabolomics data analysis tools were used to visualize the qualitative differences, showing beans to be the most widely analyzed legumes and those with the highest number of discriminant phytochemicals (n = 180, 38%). A Venn diagram showed that lentils, beans, soybeans, and chickpeas shared only 7% of their compounds. This work highlighted the huge chemical diversity among legumes and identified the need for further research in this field and the use of metabolomics as a promising tool to achieve it.

Co-fermentation of lentils using lactic acid bacteria and Bacillus subtilis natto increases functional and antioxidant components

We identified lentil products with both nutritional value and antioxidant capacity by studying the changes of probiotics and functional substances during single fermentation with lactic acid bacteria (LAB) or co-fermentation using LAB and Bacillus subtilis natto. After fermentation, the best growth of LAB was observed in anaerobic solid-state co-fermentation, whereby the viable counts of Lactobacillus plantarum TK9 and Lactobacillus paracasei TK1501 reached 2.77 × 109 and 2.78 × 109 CFU/g, respectively. Furthermore, the total phenol and genistin content produced by the two mixed groups, respectively, increased by 0.52- and 0.66-fold, as well as 0.63- and 0.64-fold, compared with unfermented samples. Similarly, the free amino acid content increased by 0.53- and 0.49-fold, respectively. The 50% inhibitory concentrations for the radical-scavenging against 1,1-diphenyl-2-picrylhydrazyl and α-glucosidase inhibitory activity were lower following anaerobic co-fermentation. Consistently, products of anaerobic mixed solid-state fermentation had higher oxygen radical absorbance capacity. Therefore, anaerobic solid-state co-fermentation of lentils using B. subtilis natto may promote the multiplication of LAB and enhance the antioxidant activity of fermented lentil products. PRACTICAL APPLICATION: Simple and efficient food handling is more suitable for industrial production. Co-fermentation is a good method to optimize the fermentation process. Co-culture technology has high potential in terms of functionality and antioxidant capacity.

Comparative metabolite fingerprinting of legumes using LC-MS-based untargeted metabolomics

Legumes are a well-known source of phytochemicals and are commonly believed to have similar composition between different genera. To date, there are no studies evaluating changes in legumes to discover those compounds that help to discriminate for food quality and authenticity. The aim of this work was to characterize and make a comparative analysis of the composition of bioactive compounds between Cicer arietinum L. (chickpea), Lens culinaris L. (lentil) and Phaseolus vulgaris L. (white bean) through an LC-MS-Orbitrap metabolomic approach to establish which compounds discriminate between the three studied legumes. Untargeted metabolomic analysis was carried out by LC-MS-Orbitrap from extracts of freeze-dried legumes prepared from pre-cooked canned legumes. The metabolomic data treatment and statistical analysis were realized by using MAIT R's package, and final identification and characterization was done using MSⁿ experiments. Fold-change evaluation was made through Metaboanalyst 4.0. Results showed 43 identified and characterized compounds displaying differences between the three legumes. Polyphenols, mainly flavonol and flavanol compounds, were the main group with 30 identified compounds, followed by α-galactosides (n = 5). Fatty acyls, prenol lipids, a nucleoside and organic compounds were also characterized. The fold-change analysis showed flavanols as the wider class of discriminative compounds of lentils compared to the other legumes; prenol lipids and eucomic acids were the most discriminative compounds of beans versus other legumes and several phenolic acids (such as primeveroside salycilic), kaempferol derivatives, coumesterol and α-galactosides were the most discriminative compounds of chickpeas. This study highlights the applicability of metabolomics for evaluating which are the characteristic compounds of the different legumes. In addition, it describes the future application of metabolomics as tool for the quality control of foods and authentication of different kinds of legumes.

Simultaneous analysis and measurement of uncertainty estimation of six isoflavones in Cheonggukjang by liquid chromatography-electrospray tandem mass spectrometry

A novel and simple method for detecting six isoflavones in Cheonggukjang using liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) was developed. The method validation was performed in terms of linearity, sensitivity, selectivity, accuracy and precision. The limits of detection (LODs) for the instrument employed in these experiments ranged from 0.15 μg/kg to 1.50 μg/kg, and the limits of quantification (LOQs) ranged from 0.50 μg/kg to 5.00 μg/kg. The average recoveries of the six isoflavones ranged from 82.3% to 98.9%. Before assessing the uncertainty of the measurements, we identified the factors that affect the measured value using quantitative analysis to determine how each factor affects the measurement result. It was found that the sample weighing, standard material purity, dilution, calibration curve and reproducibility factor affect the uncertainty of measurement. The developed method was specific and reliable. Therefore, the method is suitable for the routine analysis of isoflavones in Cheonggukjang.

Is Chickpea a Potential Substitute for Soybean? Phenolic Bioactives and Potential Health Benefits

Legume seeds are rich sources of protein, fiber, and minerals. In addition, their phenolic compounds as secondary metabolites render health benefits beyond basic nutrition. Lowering apolipoprotein B secretion from HepG2 cells and decreasing the level of low-density lipoprotein (LDL)-cholesterol oxidation are mechanisms related to the prevention of cardiovascular diseases (CVD). Likewise, low-level chronic inflammation and related disorders of the immune system are clinical predictors of cardiovascular pathology. Furthermore, DNA-damage signaling and repair are crucial pathways to the etiology of human cancers. Along CVD and cancer, the prevalence of obesity and diabetes is constantly increasing. Screening the ability of polyphenols in inactivating digestive enzymes is a good option in pre-clinical studies. In addition, in vivo studies support the role of polyphenols in the prevention and/or management of diabetes and obesity. Soybean, a well-recognized source of phenolic isoflavones, exerts health benefits by decreasing oxidative stress and inflammation related to the above-mentioned chronic ailments. Similar to soybeans, chickpeas are good sources of nutrients and phenolic compounds, especially isoflavones. This review summarizes the potential of chickpea as a substitute for soybean in terms of health beneficial outcomes. Therefore, this contribution may guide the industry in manufacturing functional foods and/or ingredients by using an undervalued feedstock.

Utilization of atmospheric solids analysis probe mass spectrometry for analysis of fatty acids on seed surface

Atmospheric solids analysis probe mass spectrometry (ASAP-MS) was used for the first time for direct surface analysis of plant material. It can be readily used for surface analysis of whole and intact pea seeds and their seed coats, and for the study of the profile of fatty acids on the outer surface. Furthermore, ASAP-MS in combination with multivariate statistics allowed classification of pea genotypes with respect to physical dormancy and investigation of related biological markers. Hexacosanoic and octacosanoic acids were suggested to be important markers likely influencing water transport through the seed coat into the embryo (with the highest significance for dormant L100 genotype). ASAP-MS provided higher selectivity and better signal of fatty acids compared to (MA)LDI-MS (laser desorption ionization mass spectrometry either matrix free or matrix assisted) providing on the other hand spatial distribution information and results obtained by both methods are mutually supportive. The developed ASAP-MS method and obtained results can be widely utilized in biological, food, and agricultural research. Graphical abstract ᅟ.

Consumption of Decorticated Pulses Ensures the Optimum Intake of Isoflavones by the Urban Indian Population

Sample urban population was assessed for consumption of legumes. Genistein and daidzein content of commonly consumed legumes was evaluated to estimate the isoflavone intake through the consumption of these legumes by selected population. Total genistein content of all legumes considered for analysis was found to be in the range of 0.60 to 8.65 mg per 100 g whereas total daidzein content was found to be in the range of 1.10 to 30.37 mg per 100 g in selected legumes. Chickpea, kabuli, whole (Cicer arietinum), pigeon pea, split, decorticated (Cajanus cajan), chickpea, split, decorticated (Cicer arietinum) showed a high amount of genistein and daidzein among selected legumes. Average isoflavone consumption by selected population was found to be 18.22 mg/d through the consumption of legumes. Consumption of pigeon pea (split, decorticated) and chickpea (split, decorticated) was found to be highest at 371.6 g/month and 329.7 g/month, and hence were found to contribute 18% and 14% to total isoflavone intake, respectively. The comparatively high content of isoflavones and inclusion as a staple in the diet have resulted in making the split, decorticated pulses (chickpea, pigeon pea, lentil, green gram, black gram) a chief isoflavone source for selected population irrespective of their demographic differences.

High resolution LC-ESI-TOF-mass spectrometry method for fast separation, identification, and quantification of 12 isoflavones in soybeans and soybean products

A high resolution LC-ESI-TOF-MS analytical method was established for the rapid isolation, identification, and quantification of 12 isoflavones in soybean and soybean products. Individual isoflavones were identified on the basis of the accurate mass data of their respective protonated mass ions, Na or K adduct ions, fragment ions, and isotope ion patterns. The protonated mass ions of isoflavones were extracted for their quantification in soybean products. Twelve different isoflavones in the soybean products were fully separated, identified and quantified within 12min separation time. The established LC-TOF/MS was an effective analytical method for the simultaneous characterization and quantification of isoflavones with exceptionally short analytical time, high selectivity, a high linearity (r(2)>0.992) in a wide range, low LOD and LOQ, high precision, inter-and intra-day repeatability, and no significant matrix effect. Furthermore, it requires simple sample preparation procedure (solvent extraction, dilution, and syringe filtration).

Antioxidants: Characterization, natural sources, extraction and analysis

Recently many review papers regarding antioxidants from different sources and different extraction and quantification procedures have been published. However none of them has all the information regarding antioxidants (chemistry, sources, extraction and quantification). This article tries to take a different perspective on antioxidants for the new researcher involved in this field. Antioxidants from fruit, vegetables and beverages play an important role in human health, for example preventing cancer and cardiovascular diseases, and lowering the incidence of different diseases. In this paper the main classes of antioxidants are presented: vitamins, carotenoids and polyphenols. Recently, many analytical methodologies involving diverse instrumental techniques have been developed for the extraction, separation, identification and quantification of these compounds. Antioxidants have been quantified by different researchers using one or more of these methods: in vivo, in vitro, electrochemical, chemiluminescent, electron spin resonance, chromatography, capillary electrophoresis, nuclear magnetic resonance, near infrared spectroscopy and mass spectrometry methods.

Profiling of phenolic and other compounds from Egyptian cultivars of chickpea (Cicer arietinum L.) and antioxidant activity: a comparative study

The metabolic profiling of seven Egyptian cultivars of chickpeaviaRP-HPLC-DAD-ESI-QTOF-MS enabled the characterization of 96 phenolic compounds.

Development and validation of a high-resolution LTQ Orbitrap MS method for the quantification of isoflavones in wastewater effluent

Isoflavones and coumestranes are the most important classes of compounds among phytoestrogens; by binding to estrogen receptors, they mimic or modulate the effect on the endogenous receptors. Little information can be found in literature about the presence of isoflavones and coumestrol in the environment, even if it is known that this may have significance, being these substances classified as endocrine disrupting compounds. In this research, we aim to explore the capabilities of the LTQ Orbitrap Discovery hybrid MS in full-scan acquisition mode, with high resolution, to validate an analytical method for the quantification of nine isoflavones (genistein, genistin, glycitein, daidzein, daidzin, (R,S)-equol, biochanin A, formononetin and coumestrol) in wastewater samples. The correlation coefficients of calibration curves of the nine analyzed compounds were in a range of 0.996-0.999; recoveries at two different levels of concentration (0.05 and 0.5 µg/l) were in the range 73-98%, and the limits of detection ranged between 0.0014 and 0.017 µg/l, proving that this method is sensitive enough in comparison with other methods available in literature. This method has been applied for the analysis of 20 wastewater treatment plants in County Cork, Ireland.

Occurrence of isoflavonoids in Brazilian common bean germplasm (Phaseolus vulgaris L.)

Common bean (Phaseolus vulgaris) is present in the daily diet of various countries and, as for other legumes, has been investigated for its nutraceutical potential. Thus, 16 genotypes from different gene pools, representing seven types of seed coats and different responses to pathogens and pests, were selected to verify their isoflavone contents. The isoflavonoids daidzein and genistein and the flavonols kaempferol, myricetin, and quercetin were found. Grains of the black type showed the highest concentrations of isoflavonoids and were the only ones to exhibit daidzein. IAC Formoso, with high protein content and source of resistance to anthracnose, showed the greatest concentration of genistein, representing around 11% of the content present in soybean, as well as high levels of kaempferol. Arc 1, Raz 55, and IAC Una genotypes showed high content of coumestrol. The results suggest the use of IAC Formoso to increase the nutraceutical characteristics in common bean.

Comparative study of the methodology used in the extraction of isoflavones from legumes applying a modified QuEChERS approach

INTRODUCTION

Isoflavones are phytochemicals of great interest because of their association with a large variety of positive effects on human health. The major sources of isoflavones in the diet are plants of the Leguminosae family, especially soybeans, although many other legumes more widely consumed in the Mediterranean diet have also been reported to contain these compounds. In previous work we extracted isoflavones from samples using a modified QuEChERS (Quick Easy Cheap Effective Rugged Safe) methodology.

OBJECTIVE

To compare different methods for placing the sample and the solvent in contact to optimise the extraction of isoflavones from legumes (chickpeas, lentils and white beans) using a modified QuEChERS methodology.

METHOD

Five different approaches to sample agitation were tested: vortex agitation, thermostatted stirring agitation and thermostatted tray shaking, and a thermostatted ultrasound bath and an ultrasound probe. To evaluate the different methodologies a modified QuEChERS approach was used as the extraction method. The separation and quantification of isoflavones was carried out using liquid chromatography-triple quadrupole/mass spectrometry (LC-MS/MS).

RESULTS

The best methods were found upon using a thermostatted shaking tray for the extraction of chickpeas and white beans and the ultrasound probe for lentil samples. These methods were chosen based on the highest amount of analytes obtained as well as the best recovery values.

CONCLUSION

Determination of isoflavones in foods may be affected by the different methods used to place the sample and the solvent in contact in the extraction step. The main advantages of the proposed extraction procedures are their simplicity, speed, reliability and low cost.