Isoflavone Content Research Articles

Enhancing aglycone isoflavones in soymilk through soybean germination and incubation

As a group of important bioactive compounds in soybeans, isoflavones are beneficial to human health, and aglycone isoflavones are more readily absorbed and utilized by the human body. Soymilk is a widely consumed soy-based beverage. The reduction in isoflavones content during soymilk production can lower its nutritional quality. This study aimed to increase the total isoflavones content and the proportion of aglycone isoflavones in soymilk through seeds germination and the followed soymilk incubation. In this study, changes in the isoflavone content and composition of soymilk made from germinated and raw soybeans were detected at different processing stages. Single-factor and response surface experiments were carried out to optimize the incubation conditions, aiming to enhance the content of aglycone isoflavones in soymilk made of germinated soybeans. The results showed that total isoflavones content increased from 3722.23 μg/g DW to 4337.93 μg/g DW in 2-day germinated soybeans, and incubation promoted the conversion of conjugated isoflavones to aglycone isoflavones in soymilk. Under the optimal incubation conditions (53.26 ± 1.0 °C for 56.64 ± 1.0 min), the content of aglycone isoflavones in soymilk significantly increased by 44.43% compared with the control, and the incubation with optimized conditions had little effect on its microbial safety, nutrients content and overall flavor, consequently leading to no significant deterioration in its quality after incubation. Therefore, the combination of germination and incubation is an efficient strategy to enhance the aglycone isoflavones content in soymilk, providing valuable information for enhancing the isoflavones bioactivity of soymilk during processing.

Genome-wide analysis of the R2R3-MYB gene family and identification of candidate genes that regulate isoflavone biosynthesis in red clover (Trifolium pratense)

Red clover (Trifolium pratense) is a perennial legume with high feeding and medicinal value attributed to its abundant isoflavone content. Previous studies reported that R2R3-MYB transcription factors are involved in the biosynthesis of isoflavones; however, their specific role in red clover remains poorly understood. Through comprehensive genome-wide and transcriptome analyses, a total of 138 TpR2R3-MYB genes were identified and classified into 30 distinct subgroups within a phylogenetic tree. Importantly, six of these subgroups showed associations with isoflavone biosynthesis in red clover. The majority of segmental duplication events (Ka/Ks < 1) indicated that the TpR2R3-MYB gene underwent strong purifying selection during evolution. The qRT-PCR analysis demonstrated high expression levels of TpMYB79 and TpMYB53 in Minshan red clover at full flowering stage, consistent with the trend for isoflavone content determination, suggesting that TpMYB79 and TpMYB53 might be important regulators of isoflavone biosynthesis in red clover. Additionally, we observed nucleus and vacuole membrane localization of TpMYB53 and TpMYB79, with TpMYB53 primarily exerting transcriptional activation through its C-terminal activation motifs while TpMYB79 exhibited no transcriptional activity. These findings provided a foundation for the study of the biological function of R2R3-MYB transcription factors in red clover.

Comprehensive analysis of soybean (Glycine max L.) by-products: nutritional value, phenolic composition, and bioactive properties

Soybeans are key components in vegetable beverage production, generating two by-products: soybean hulls and okara. For every ton of soybeans, 50-80 kg of hulls and 120 kg of okara are produced, being often discarded or used in low-value applications like fertilizers or feed. This study aims at characterizing their biochemical and nutritional profiles to assess their potential reintroduction into the food chain. Both by-products have high levels of protein and dietary fiber, mainly insoluble. Okara and hulls predominantly contain oleic acid and linoleic acid, respectively. Seventeen phenolic compounds, mainly isoflavones, were identified, with genistein as the main compound. Hulls exhibit superior antioxidant activity compared to okara. Neither extract showed cytotoxicity or anti-inflammatory effects and exhibited limited antimicrobial activity. However, both demonstrate prebiotic potential, promoting beneficial gut bacteria growth. The results suggest that these by-products have significant potential as new ingredients for their protein, isoflavone, and fiber content, alongside prebiotic properties.

Diversity Analysis and Comprehensive Evaluation of 101 Soybean (Glycine max L.) Germplasms Based on Sprout Quality Characteristics.

Soybean sprouts are a common culinary vegetable due to their high nutrition and tasty flavors. To select soybean varieties with excellent sprout quality, 101 soybean materials were collected from different regions of China, and eight sprout quality parameters were determined for overall evaluation. The results showed that eight sprout quality parameters achieved varying degrees of difference and correlation. Based on the principal component analysis (PCA), three principal components were extracted, with a cumulative contribution rate of 78.314%. Further, the comprehensive evaluation value (D) of soybean sprout quality was calculated by membership function analysis based on PCA, and the quality of soybean sprouts was ranked accordingly. Subsequently, a regression equation for the prediction of soybean sprout quality was established using a stepwise regression analysis, and the model showed a good prediction performance (correlation coefficient of prediction > 0.8; residual predictive deviation > 2.0). On these grounds, it was proposed that the quality of soybean sprouts could be comprehensively predicted by four parameters: hypocotyl length, edible rate, 100-seed weight, and total isoflavone content and saponin content. In conclusion, this study provides excellent varieties for soybean sprout production and new variety breeding, and it provides an important reference for the prediction of soybean sprout quality.

Effects of high hydrostatic pressure on folate and isoflavone contents, bioaccessibility, and physicochemical properties of soybean powder

Effects of high hydrostatic pressure on folate and isoflavone contents, bioaccessibility, and physicochemical properties of soybean powder

Contrasting germination behavior of nodding broomrape towards soybean seeds- and sprouts-extract is associated with their corresponding phytohormones, sugars and isoflavones contents

Contrasting germination behavior of nodding broomrape towards soybean seeds- and sprouts-extract is associated with their corresponding phytohormones, sugars and isoflavones contents

Ozone treatment increase the whiteness of soy protein isolate through the degradation of isoflavone

The color of soy protein isolate (SPI) influences the appearance of products such as tofu and soymilk, consequently impacting consumer preferences. Typically, whiter-colored SPIs were more favorite. However, products currently manufactured in the industry predominantly exhibit a yellowish hue. In our study, the incorporation of gaseous ozone into the production process of SPI notably improved its appearance on color. Simultaneously, a reduction in the isoflavone content enriched in SPI due to ozone treatment was observed, suggesting a potential mechanism for improving the whiteness of SPI. In addition, we discovered that the introduction of ozone for different times oxidized ozone-sensitive sulfhydryl groups, tryptophan, and tyrosine in proteins, thereby affecting the protein structure. This finding was determined through the analysis of free sulfhydryl groups, disulfide bonds, SDS-PAGE electrophoresis, FTIR, and endogenous fluorescence spectroscopy of SPIs. Meanwhile, the ozone treatment did not induce protein aggregation or alter its functional properties.

Mild water deficit at seed filling stage promotes drought-tolerant soybean production formation and flavonoids accumulation

Soybean is an important crop for both grain and oil use. Appropriate agricultural managements increase crop productivity quantity and chemical nutrition quality. This study utilized two soybean varieties HN44(drought-tolerant) and SN14 (drought-sensitive)to analyze mechanism effect of light drought stress on instantaneous water use efficiency(WUEi), yield and isoflavone content by changes in the transcriptome and metabolome during the early seed-filling stage. The results showed that light drought stress can improve WUEi, stimulate the yield potential and increase the content of Daidzin and 6''-O-malonyldaidzin of HN44. In addition, under light drought stress, the differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) in HN44 and SN14 were significantly enriched in the biosynthetic pathways of flavonoids and isoflavones. The flavonoid metabolites in HN44 increased, while those in SN14 decreased. Through the different expression patterns of DEGs and DAMs in the two varieties, differential genes and differential metabolites were screened out, such as CHS, HCT, F3H, HIDH, IF7GT, VR, p-coumaroylquinic, and 6''-O-Malonylglycitin. These genes and metabolites can provide theoretical basis for the selection breeding of drought-tolerant soybean varieties and the evaluation of drought-resistant resources. The findings provided important agronomic strategies for improving the yield, bioactive substances, and water resource management of crop soybeans.

R2R3-MYB transcription factor GmMYB68 is involved in the accumulation of soybean isoflavones

We aimed to investigate the regulatory function of the soybean transcription factor R2R3-MYB (GmMYB68) in isoflavone biosynthesis. Through comprehensive subcellular and chromosomal localization analyses, we found that GmMYB68 was predominantly localized to the nucleus and mapped to chromosome Gm04. Notably, SSR markers near this gene significantly correlated with seed isoflavone content. GmMYB68 overexpression markedly increased isoflavone contents, confirming its positive role in regulating isoflavone synthesis. GmMYB68 also played a crucial role in the response of soybean to abiotic stress. Using RNA-seq and yeast one-hybrid techniques, we discovered an intricate interaction between GmMYB68 and key isoflavone biosynthesis genes GmCHS7 and GmCHS8. These findings provide novel insights into the mechanisms underlying isoflavone biosynthesis. Furthermore, using yeast two-hybrid experiments, we identified proteins interacting with GmMYB68, suggesting roles in the synthesis of physiologically active compounds and abiotic stress response. We not only elucidated the regulatory mechanisms of GmMYB68 in isoflavone biosynthesis and abiotic stress response but also constructed a molecular network encompassing GmMYB68, GmCHS7, and GmCHS8. This network provides a theoretical basis for a better understanding of and strategies for improving soybean isoflavone biosynthesis.

The Potential of Biotic Elicitors to Increase Isoflavone Production (Pachyrhizus erosus L.) Callus

Abstract The isoflavones contained in the Pachyrhizus plant (Pachyrhizus erosus Linn) have multiple functions, including serving as raw materials for the health/pharmacology or cosmetic industries. Isoflavones are beneficial as antioxidants, and cholesterol reducers and are capable of neutralizing free radicals and delaying aging. Tissue culture techniques are widely used to produce secondary metabolite compounds. Isoflavones can be made in vitro through callus production by tissue culture. By using elicitation techniques with the addition of various glucose concentrations to the culture media (media Murashige and Skoog or Vacin and Went), it is expected to increase the quantity and quality of callus and the content of secondary metabolites (Isoflavones) in Pachyrhizus callus. The research aims to increase the production of Isoflavones in Pachyrhizus callus by adding elicitors with various concentrations of glucose. The research method used a completely randomized factorial design. Factor I: two levels of basic media: M1 (Murashige and Skoog Media) and M2 (Vacin and Went Media). Factor II: Addition of Glucose concentrations with seven levels: 0%, 5%, 10%, 15%, 20%, 25%, 30%. The plant material used was the young leaves of Pachyrhizus. The results of the study showed that (1) all formed callus exhibited compact quality; (2) the addition of 30% glucose concentration resulted in the best growth of callus; (3) the highest Isoflavone content (0.15%) was found in the callus of Pachyrhizus erosus L. due to the treatment with both MS and VW media with 20% Glucose Elicitor

Anticancer effects of washed-dehydrated solar salt doenjang and its metabolites

AbstractIn this study, the anticancer effect of doenjang according to the type of salt was investigated. Three samples were prepared: doenjang made with purified salt, doenjang made with generally manufactured solar salt, and doenjang made with washed and dehydrated solar salt (WDSD). In mice in which colon cancer was induced with azoxymethane/dextran sodium sulfate, doenjang made with solar salt, especially doenjang made with washed and dehydrated solar salt, was found to have a much higher colon cancer inhibition effect. WDSD significantly promoted the mRNA expression of apoptosis-related factors such as Bcl-2–associated X protein (Bax) and caspase 9 and the cell cycle arrest-related factors p53 and p21, and conversely significantly reduced the mRNA expression of apoptosis inhibitors such as B-cell lymphoma-2 (Bcl-2) (p &lt; 0.05). Additionally, metabolites were investigated to determine which substances in WDSD exhibit this anticancer effect. As a result, the contents of isoflavone and soyasaponin B in the form of aglycons such as genistein, daidzein, and glycitein, which are known to have anticancer and anti-inflammatory properties, were found to be significantly high. Therefore, the results confirmed that doenjang prepared with washed and dehydrated solar salt has superior anticancer potential against colon cancer, and that various active ingredients contribute to the improvement of this functionality.

Bioinformatics Identification and Expression Analysis of Acetyl-CoA Carboxylase Reveal Its Role in Isoflavone Accumulation during Soybean Seed Development.

Isoflavones belong to the class of flavonoid compounds, which are important secondary metabolites that play a crucial role in plant development and defense. Acetyl-CoA carboxylase (ACCase) is a biotin-dependent enzyme that catalyzes the conversion of Acetyl-CoA into Malonyl-CoA in plants. It is a key enzyme in fatty acid synthesis and also catalyzes the production of various secondary metabolites. However, information on the ACC gene family in the soybean (Glycine max L. Merr.) genome and the specific members involved in isoflavone biosynthesis is still lacking. In this study, we identified 20 ACC family genes (GmACCs) from the soybean genome and further characterized their evolutionary relationships and expression patterns. Phylogenetic analysis showed that the GmACCs could be divided into five groups, and the gene structures within the same groups were highly conserved, indicating that they had similar functions. The GmACCs were randomly distributed across 12 chromosomes, and collinearity analysis suggested that many GmACCs originated from tandem and segmental duplications, with these genes being under purifying selection. In addition, gene expression pattern analysis indicated that there was functional divergence among GmACCs in different tissues. The GmACCs reached their peak expression levels during the early or middle stages of seed development. Based on the transcriptome and isoflavone content data, a weighted gene co-expression network was constructed, and three candidate genes (Glyma.06G105900, Glyma.13G363500, and Glyma.13G057400) that may positively regulate isoflavone content were identified. These results provide valuable information for the further functional characterization and application of GmACCs in isoflavone biosynthesis in soybean.

Contextualized Metabolic Modelling Revealed Factors Affecting Isoflavone Accumulation in Soybean Seeds.

Isoflavones, secondary metabolites with numerous health benefits, are predominantly found in legume seeds, especially soybean; however, their contents in domesticated soybean seeds are highly variable. Wild soybeans are known for higher seed isoflavone contents than cultivars. Here we used experimental and modelling approaches on wild soybean (W05) and cultivated soybean (C08) to delineate factors influencing isoflavone accumulation. We found imported nutrients were converted into storage compounds, with isoflavone accumulation in W05 seeds being faster than in C08 ones. The isoflavone accumulation during seed development was simulated using context-specific cotyledon metabolic models of four developmental stages on cultivar C08, and the metabolic burden imposed by increasing biomass was evaluated. Trade-off analyses between biomass and isoflavone suggest that high biomass requirement in cultivars could limit the reallocation of resources for secondary metabolite production. Isoflavone production in mature seeds was also influenced by biomass compositions. Seeds with higher carbohydrate contents favour isoflavone production, while those with highest protein and oil contents had lowest isoflavone contents. Although seeds could synthesize isoflavones on their own, the predicted fluxes from biosynthesis alone were lower than the empirical levels. Shadow price analyses indicated that isoflavone accumulation depended on both intrinsic biosynthesis and direct contribution from the plant.

Fermentation with Bacillus natto and Bifidobacterium improves the functional, physicochemical properties, and taste qualities of coix seed-natto

Coix seed-natto (CS-natto) is a nutritious food rich in various functional components such as nattokinase (NK), and the strains’ fermentation is crucial for enhancing its quality. This work utilized Bacillus natto GUTU09 (B9) and Bifidobacterium animalis subsp. lactis BLH1 or BLH6 to ferment soybeans that were soaked in a saccharified liquid made from CS, resulting in the preparation of CS-natto, studied the physicochemical and functional characteristics during fermentation, and analyzed the correlation of various indicators. Finally, an electronic tongue analysis was conducted on CS-natto. The results indicated that fermentation significantly increases NK and antioxidant activity in CS-natto, with NK activity in BLH6-B9 natto reaching 425.00 FU/g. Co-fermentation notably enhanced the content and composition of phenolic substances. Furthermore, the study revealed that the organic acid and soy isoflavone content in co-fermentation were significantly higher than in single-strain fermentation. Fermentation could elevate the levels of amino peptide nitrogen and soluble peptides. Additionally, the addition of Bifidobacterium exhibited a synergistic effect on the fermentation of B9 to produce natto. Correlation analysis indicated that Bifidobacterium promoted B9 to produce NK. The BLH1 encouraged the conversion of organic acids. Daidzein and daidzin were positively correlated (P<0.01), suggesting a potential mutual conversion. Finally, electronic tongue analysis indicated that co-fermentation could effectively enhance the taste. The results indicated that CS-natto could serve as an improved dietary supplement offering enhanced quality and more beneficial effects on people’s health.

High-quality genome of a modern soybean cultivar and resequencing of 547 accessions provide insights into the role of structural variation.

Soybean provides protein, oil and multiple health-related compounds. Understanding the effects of structural variations (SVs) on economic traits in modern breeding is important for soybean improvement. Here we assembled the high-quality genome of modern cultivar Nongdadou2 (NDD2) and identified 25,814 SV-gene pairs compared to 29 reported genomes, with 13 NDD2-private SVs validated in 547 deep-resequencing (average = 18.05-fold) accessions, which advances our understanding of genomic variation biology. We found some insertions/deletions involved in seed protein and weight formation, an inversion related to adaptation to drought and a large intertranslocation implicated in a key divergence event in soybean. Of 749,714 SVs from 547 accessions, 6,013 were significantly associated with 22 yield-related and seed-quality-related traits determined in ten location × year environments. We uncovered 1,761 associated SVs that hit genes or regulatory regions, with 12 in GmMQT influencing oil and isoflavone contents. Our work provides resources and insights into SV roles in soybean improvement.

Transcriptome and Metabolomic Analyses Reveal Tissue-Specific Glycosylation of Phenylpropanoids and Flavonoids in Toxicodendron vernicifluum.

Toxicodendron vernicifluum (Stokes) F. A. Barkley is a tree species used primarily for lacquer production. Our study utilized transcriptome and metabolomic analysis to investigate the biosynthesis of phenylpropanoids and flavonoids, specifically the glycosylated forms, in T. vernicifluum roots, stems, and leaves. HPLC-QTOF-MS/MS identified 186 compounds, with tissue-specific distributions revealed by PCA. Flavonoids and phenylpropanoids glycosides were significantly more abundant in leaves compared with roots and stems. Full-length sequencing uncovered 17,266 transcripts in T. vernicifluum. Gene expression analysis showed higher activity of phenylpropanoid and flavonoid biosynthesis pathways in leaves. Certain genes, such as CYP73A, 4CL, CRR, CYP84A/F5H, and CYP93C, displayed associations with compound content distributions. Root tissue exhibited a higher concentration of isoflavones. Notably, glycosyltransferase expression demonstrated significant correlations with glycosylated compounds' content. Biochemical validation confirmed the involvement of TvPB_c0_g2904, encoding a UDP-glucosyltransferase, in genistin biosynthesis in T. vernicifluum.

Soybean plants enhance growth through metabolic regulation under heterogeneous drought stress

Heterogeneous drought stress (HED) is prevalent in drought-resistant practices such as deficit irrigation, root zone irrigation and strip intercropping. The mechanisms and improvement of crop drought resistance under HED are not fully understood. This study used double-root grafted Nandou 12 (ND12) soybean seedlings to simulate HED treatment under controlled conditions. Seedlings were transplanted into root cups with waterproof partitions to establish different soil moisture treatments: sufficient irrigation (SI) with 80 % soil moisture on both sides, HED with 80 % on one side and 40 % on the other, and homogeneous drought stress (HOD) with 60 % on both sides. The results indicated that soybean plants treated with HED exhibited healthier growth compared to those treated with HOD. Photosynthesis rate (Pn), stomatal conductance (cond.), transpiration rate (Tr), and relative water content (RWC) decreased by 10.24 %, 43.90 %, 152.66 %, and 8.69 % in HED-treated plants, respectively, but dry biomass increased by 3.38 %. Conversely, HOD conditions led to a significant decline in these parameters. Metabolomic and transcriptomic analyses revealed significant changes in the biosynthesis and signaling pathways of key phytohormones and metabolites, including abscisic acid (ABA), gibberellin (GA), jasmonic acid (JA), isoflavones, starch, and sugars. In HED-treated plants, GmNCED downregulation resulted in 54.22 % less ABA than HOD. GA levels increased under HED with upregulation of GmGA3OX1 and GmGA3OX2. JA content in HED-treated roots was 90.90 % higher than in HOD-treated roots. Isoflavones concentration including genistein (73.01 %), genistin (63.63 %), malonylgenistin (20.58 %), malonylgenistin (65 %), diadzin (38.15 %), and malonyldiadzin (47.61 %) levels, were significantly higher in HED-treated plants. Antioxidant enzyme activities indicated a 20 % increase in peroxidase (POD) activity under HED, while malondialdehyde (MDA) content was 27 % higher in HOD-treated plants, indicating greater oxidative stress. Chlorophyll content remained stable, and starch concentration increased by 33.33 % in HED-treated plants compared to HOD-treated plants. HED enhances phytohormonal responses and metabolic adjustments in soybean plants, boosting photosynthetic efficiency, antioxidant capabilities, growth, and drought resilience. This regulatory mechanism balances growth promotion and drought resistance, highlighting HED potential in improving crop resilience.

Joint GWAS and WGCNA Identify Genes Regulating the Isoflavone Content in Soybean Seeds.

Isoflavone is a secondary metabolite of the soybean phenylpropyl biosynthesis pathway with physiological activity and is beneficial to human health. In this study, the isoflavone content of 205 soybean germplasm resources from 3 locations in 2020 showed wide phenotypic variation. A joint genome-wide association study (GWAS) and weighted gene coexpression network analysis (WGCNA) identified 33 single-nucleotide polymorphisms and 11 key genes associated with soybean isoflavone content. Gene ontology enrichment analysis, gene coexpression, and haplotype analysis revealed natural variations in the Glyma.12G109800 (GmOMT7) gene and promoter region, with Hap1 being the elite haplotype. Transient overexpression and knockout of GmOMT7 increased and decreased the isoflavone content, respectively, in hairy roots. The combination of GWAS and WGCNA effectively revealed the genetic basis of soybean isoflavone and identified potential genes affecting isoflavone synthesis and accumulation in soybean, providing a valuable basis for the functional study of soybean isoflavone.

Moderate Drought Stress Interferes with the Physiological State and Promotes the Accumulation of Isoflavone in Reproductive Iris domestica Rhizomes

Drought stress is one of the main factors affecting the growth and secondary metabolism of plants. Iris domestica, rich in isoflavones, is a common herbal medicine in China. In this study, the effects of drought stress and rehydration on resistance physiological characteristics and the secondary metabolism of two-year-old I. domestica during the vegetative and reproductive growth period were investigated. The results showed that the dry weight and fresh weight of rhizomes and roots under severe drought stress were significantly decreased, while those under moderate drought stress were not significantly changed. Meanwhile, the SOD activities, POD activities, MDA content and Pro content increased to resist drought at D1 and D2. In the vegetative growth period, the changes in isoflavone concentration and the expression levels of genes in isoflavone synthesis were more dramatic. Isoflavone accumulation was promoted, to some extent, in the reproductive growth period under the D1 drought treatment. In the actual production process, different measures, namely short-term stress regulation in the vegetative growth period and moderate drought stress (13.44% &lt; soil water content ≤ 16.8%) in the reproductive growth period, need to be adopted to regulate isoflavone biosynthesis.

UV-B Radiation Exhibited Tissue-Specific Regulation of Isoflavone Biosynthesis in Soybean Cell Suspension Cultures.

Isoflavones, a class of substances with high biological activity, are abundant in soybeans. This study investigated isoflavone biosynthesis in soybean cell suspension cultures under UV-B radiation. UV-B radiation enhanced the transcription level and activity of key enzymes involved in isoflavone synthesis in cell suspension cultures. As a result, the isoflavone contents significantly increased by 19.80% and 91.21% in hypocotyl and cotyledon suspension cultures compared with the control, respectively. Meanwhile, a significant difference was observed in the composition of isoflavones between soybean hypocotyl and cotyledon suspension cultures. Genistin was only detected in hypocotyl suspension cultures, whereas glycitin, daidzein, and genistein accumulated in cotyledon suspension cultures. Therefore, UV-B radiation exhibited tissue-specific regulation of isoflavone biosynthesis in soybean cell suspension cultures. The combination of suspension cultures and abiotic stress provides a novel technological approach to isoflavone accumulation.