8-Hydroxydaidzein, an aldose reductase inhibitor from okara fermented with Aspergillus sp. HK-388

The aldose reductase (AR) inhibitor, 8-hydroxydaidzein, was isolated and identified from a methanolic extract of okara (soybean pulp) fermented with the fungal strain, Aspergillus sp. HK-388. 8-Hydroxydaidzein showed non-competitive inhibition of human recombinant AR with respect to DL-glyceraldehyde, its Ki value being evaluated as 7.0 microM.     

Isolation of 8-hydroxyglycitein and 6-hydroxydaidzein from soybean miso

We isolated from soybean miso 8-hydroxyglycitein and 6-hydroxydaidzein as DPPH-radical scavengers, and elucidated their chemical structures by mass spectrometric, and (1)H- and (13)C-NMR spectrosopic analyses. These compounds showed DPPH-radical scavenging activity as high as that of alpha-tocopherol, 8-hydroxygenistein and 8-hydroxydaidzein. This is the first report of the isolation of 8-hydroxyglycitein from a natural source.     

Metabolism of the soy isoflavones daidzein and genistein by fungi used in the preparation of various fermented soybean foods

The ability of fungi used in the preparation of fermented soybean foods to metabolize the soy isoflavones daidzein and genistein was investigated. A total of 21 fungal strains from dou-chi, miso, sake, soy sauce, and sufu were screened. The genera of the tested fungi included Actinomucor, Aspergillus, Candida, Debaryomyces, Monascus, Mucor, Rhizopus, Saccharomyces, and Zygosaccharomyces. The results were that all tested Aspergillus strains from these soybean foods, including five A. oryzae strains, one A. sojae strain, and one A. tamarii strain, metabolized both daidzein and genistein. In contrast, no other tested fungi from the fermented soybean foods metabolized either daidzein or genistein. The metabolites of daidzein and genistein by Aspergillus strains were identified as 8-hydroxydaidzein and 8-hydroxygenistein, respectively, based on their mass, (1)H-, and (13)C-NMR spectra.     

Effect of pretreatment with paste and sauce extract made using Tenebrio molitor larvae on ethanol‐damaged HepG2 cells

In this study, we made koji using protein‐rich Tenebrio molitor larvae (TML) inoculated with Aspergillus oryzae, and then used the koji to prepare a paste and a sauce. The TML koji showed the highest amino nitrogen, protease activity, and free amino acids content when it was fermented for 72 h after inoculation with 0.8% A. oryzae. The koji was aged in 20% saltwater for 50 days, and then the paste and sauce were separated. To evaluate the effect of TML paste and sauce on ethanol (EtOH)‐damaged hepatocytes, aspartate aminotransferase (AST) and alanine aminotransaminase (ALT) were measured in EtOH‐treated HepG2 cells after pretreatment with TML paste and sauce extract. As a result, we confirmed that TML paste and sauce extracts lowered the AST and ALT content in the medium, compared to soybean sauce and paste extracts. TML paste and sauce extract significantly reduced the expression of tumor necrosis factor (TNF)‐α and interleukin (IL)‐6, a biomarker of inflammation, and significantly increased the activity of the antioxidants superoxide dismutase (SOD) and reduced glutathione (GSH) in proportion to the amount of TML added to the paste and sauce. These results suggest that the intake of TML paste and sauce, a new type of fermented food made from insects, may provide effective protection to the liver against hepatocyte injury by EtOH via anti‐inflammatory and antioxidative effects.     

Isolation of 8-Hydroxyglycitein and 6-Hydroxydaidzein from Soybean Miso

We isolated from soybean miso 8-hydroxyglycitein and 6-hydroxydaidzein as DPPH-radical scavengers, and elucidated their chemical structures by mass spectrometric, and ¹H- and ¹³C-NMR spectrosopic analyses. These compounds showed DPPH-radical scavenging activity as high as that of α-tocopherol, 8-hydroxygenistein and 8-hydroxydaidzein. This is the first report of the isolation of 8-hydroxyglycitein from a natural source.     

8-Hydroxydaidzein,an Aldose Reductase Inhibitor from Okara Fermented with Aspergillus sp. HK-388

The aldose reductase (AR) inhibitor, 8-hydroxydaidzein, was isolated and identified from a methanolic extract of okara (soybean pulp) fermented with the fungal strain, Aspergillus sp. HK-388. 8-Hydroxydaidzein showed non-competitive inhibition of human recombinant AR with respect to DL-glyceraldehyde, its K_i value being evaluated as 7.0 μM.     

DPPH radical-scavenging compounds from dou-chi, a soybean fermented food

Dou-chi, a traditional soybean food fermented with Aspergillus sp., is usually used as a seasoning in Chinese food, and has also been used as a folk medicine in China and Taiwan. As 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavengers, four phenol compounds, one isoflavanone, eight isoflavones and one 4-pyrone have been isolated from dou-chi. Among these fourteen compounds, 3'-hydroxydaidzein, dihydrodaidzein and a 4-pyrone compound have not yet been isolated from soybean miso. The structure of the novel 4-pyrone compound, 3-((E)-2-carboxyethenyl)-5-(4-hydroxyphenyl)-4-pyrone-2-carboxylic acid was elucidated by using the same compound as that obtained from the biotransformation of daidzein. 3'-Hydroxydaidzein showed as high DPPH radical-scavenging activity as that of alpha-tocopherol, and 6-hydroxydaidzein had mushroom tyrosinase inhibitory activity with an IC(50) value of 10 muM. The order of estrogenic activity is as follows: genistein > daidzein > 3'-hydroxydaidzein > 8-hydroxygenistein, using a green fluorescent protein expression system. Furthermore, the contents of isoflavones in the fermentation process of dou-chi were measured.     

Metabolism of the Soy Isoflavones Daidzein and Genistein by Fungi Used in the Preparation of Various Fermented Soybean Foods

The ability of fungi used in the preparation of fermented soybean foods to metabolize the soy isoflavones daidzein and genistein was investigated. A total of 21 fungal strains from dou-chi, miso, sake, soy sauce, and sufu were screened. The genera of the tested fungi included Actinomucor, Aspergillus, Candida, Debaryomyces, Monascus, Mucor, Rhizopus, Saccharomyces, and Zygosaccharomyces. The results were that all tested Aspergillus strains from these soybean foods, including five A. oryzae strains, one A. sojae strain, and one A. tamarii strain, metabolized both daidzein and genistein. In contrast, no other tested fungi from the fermented soybean foods metabolized either daidzein or genistein. The metabolites of daidzein and genistein by Aspergillus strains were identified as 8-hydroxydaidzein and 8-hydroxygenistein, respectively, based on their mass, ¹H-, and ¹³C-NMR spectra.     

Antimutagenic activity of 8-hydroxyisoflavones and 6-hydroxydaidzein from soybean miso

The antimutagenic activity of four isoflavones isolated from soybean miso toward three kinds of mutagens, AF-2, MNNG, and Trp-P-1, was evaluated by the Ames test. 8-Hydroxyisoflavones had greater suppressive potency than that of daidzein, and 6-hydroxydaidzein had almost the same activity as daidzein. These results indicated the number of hydroxy and methoxy groups and the position of these functional groups were important for antimutagenic activity.     

Production of ortho-hydroxydaidzein derivatives by a recombinant strain of Pichia pastoris harboring a cytochrome P450 fusion gene

CYP57B3 from Aspergillus oryzae was recently discovered to catalyze the ortho-hydroxylation of the soyisoflavone genistein. In the present study, the gene encoding CYP57B3 was fused with the reductase domain of the CYP102A1 gene (BM3R) from Bacillus megaterium, and recombinant Pichia pastoris harboring the P450 fusion gene was evaluated for its ability to produce ortho-hydroxydaidzein derivatives from daidzein. The results showed that 8-hydroxydaidzein (8-OHDe), 3′-hydroxydaidzein (3′-OHDe), and 6-hydroxydaidzein (6-OHDe) were produced during fermentation with a maximal conversion of 2.4, 0.9, and 36.3%, respectively. The maximal yield of 6-OHDe by the recombinant strain was 9.1 mg/l. To our knowledge, both the maximal yield and the conversion efficiency of 6-OHDe from daidzein in the present study are the highest among those reported in the literatures to date. The present study is also the first to demonstrate production of ortho-hydroxydaidzein derivatives using a fusion fungus cytochrome P450 enzyme.     

Isolation of the antioxidant pyranonigrin-A from rice mold starters used in the manufacturing process of fermented foods

Rice mold starters prepared from Aspergillus species are commonly used for the manufacture of koji in the production of oriental fermented foods. Methanol extracts of rice mold starters fermented by the Aspergillus species, A. awamori, A. kawachii, A. oryzae, A. saitoi, and A. sojae, were examined for their antioxidative activity by using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging system. The extracts of A. awamori, A. kawachii, and A. saitoi exhibited higher activity than those of A. oryzae and A. sojae. An antioxidant was isolated from the extract of A. saitoi and identified as pyranonigrin-A by 1H-NMR, 13C-NMR, and FAB-MS analyses. The antioxidative activity of pyranonigrin-A was approximately equivalent to that of ferulic acid, an antioxidant in cereal grain. It was present in rice mold starters prepared by A. awamori, A. kawachii, and A. saitoi, although there was no pyranonigrin-A in the A. oryzae and A. sojae starters. The results suggest that the content of pyranonigrin-A in rice mold starters has a correlation with the antioxidative activity, and that it is induced in rice mold starters at the sporulation stage.     

1,1-Diphenyl-2-picrylhydrazyl radical-scavenging compounds from soybean miso and antiproliferative activity of isoflavones from soybean miso toward the cancer cell lines

Guided by their DPPH radical-scavenging activity, nine compounds were isolated from soybean miso. Of these, 8-hydroxydaidzein, 8-hydroxygenistein and syringic acid had as high DPPH radical-scavenging activity as that of alpha-tocopherol. The antiproliferative activity of four of the isolated isoflavones toward three cancer cell lines was examined. 8-Hydroxygenistein showed the highest activity (IC50=5.2 microM) toward human promyelocytic leukemia cells (HL-60).     

Fermented soybean meal extract improves oxidative stress factors in the lung of inflammation/infection animal model

Context

Fermented soybean products have been used in various ways, and more research is being conducted on them to reveal their benefit.

Objective

The objective of this study was to evaluate the antioxidative activity of fermented soybean meal extract by Lactobacillus plantarum in vitro and in vivo tests.

Materials and methods

A Lactobacillus plantarum strain RM10 was selected through plate and fermentation experiment, which increased the degree of protein hydrolysis (1.015 μg/mL) and antioxidant activity in soybean meal fermented by selected bacteria (FSBM). In vivo study was done on septic rats as an inflammation/infection model, and then the trial groups were treated with different concentrations of fermented soybean meal extracts (FSBM, 5, 10, and 20%).

Results

DPPH radical-scavenging and ferrozine ion-chelating activity enhanced (P < 0.05) after fermentation of soybean meal compared to control group. Reduced (P < 0.05) expression of inflammatory genes and enzymes was detected in the lungs of rats treated with fermented soybean meal extract.

Discussion and conclusions

These results demonstrated that a diet containing fermented soybean meal extract improved extreme inflammatory response in an infectious disease like sepsis by reducing inflammatory factors.

     

Determination of bioactive compounds in fermented soybean products using GC/MS and further investigation of correlation of their bioactivities

The active ingredients and bioactivities (anti-oxidant, anti-tyrosinase, anti-proliferative and estrogenic activities) of soybean and soybean products (Cheonggukjang, Meju, Makjang, Doenjang and soy sauce) produced by different fermentation processes were compared. There were high correlations between active ingredients and bioactivities. Free phenolic acids extracted from soybean products were identified and quantified by gas chromatography/mass spectrometry (GC/MS). Overall, the components and activities in fermented soybean products were different than those in soybeans. Total phenolic content (TPC), protein content (PC) and anti-oxidant activity increased as fermentation time increased. TPC and PC showed strong negative correlations with anti-oxidant activity. Doenjang and soy sauce, two long-term fermented products, showed lower total flavonoid content (TFC) and estrogenic activities than short-term fermented soybean products. This might be explained by the decomposition and hydrolysis of flavonoids due to the long fermentation time and high temperature. Strong anti-proliferative activity against cancer cell lines, which was highly correlated with TFC, was found in Meju and Cheonggukjang. Soybean and all fermented products except Meju exhibited effective tyrosinase inhibitory activities. Fermented products showed stronger estrogenic activity than soybeans, which was highly correlated with syringic acid.     

Growth of nisin-producing lactococci in cooked rice supplemented with soybean extract and its application to inhibition of Bacillus subtilis in rice miso

Lactic acid fermentation of cooked rice and rice koji by supplementation with soybean extract (SBE) and its application to rice miso fermentation were investigated. By supplementing the cooked rice with SBE, lactic acid bacteria (LAB) grew well without any unfavorable effects on the rice such as off-flavor or coloration. Lactococcus lactis subsp. lactis IFO12007 (Lc. lactis, a producer of the bacteriocin nisin) proliferated at 10(8 to approximately 9) cells/g after 24 h of incubation and produced high activity of nisin. The fermented rice with Lc. lactis strongly inhibited not only Bacillus subtilis ATCC19659 but also the other Bacillus strains. While some strains of LAB markedly inhibited the growth of Asp. oryzae, resulting in failure of koji fermentation, Lc. lactis did not affect the growth of these molds. When Lc. lactis was used for rice miso fermentation as a lactic acid starter culture, Lc. lactis rapidly proliferated and produced high nisin activity of 6,400 IU/g, in the steamed rice, resulting in complete growth inhibition of B. subtilis, which had been inoculated at the beginning of the koji fermentation. The rice miso after 12 weeks of aging had a suitable pH, and favorable taste and color. Furthermore, hyposalting of rice miso could be done without difficulty by lactic acid fermentation of both rice and soybeans.     

Traditional healthful fermented products of Japan

A variety of fermentation products, such as foods containing probiotic bacteria, black rice vinegar (kurosu), soy sauce (shoyu), soybean-barley paste (miso), natto and tempeh, are sold in food stores in Japan. These fermented food products are produced by traditional methods that exploit mixed cultures of various non-toxic microorganisms. These microorganisms include lactic acid bacteria, acetic acid bacteria, sake yeast, koji molds and natto bacteria. Many traditional fermented foods have been studied and their effects on metabolism and/or immune system have been demonstrated in animal and/or human cells. This review summarizes the scientific basis for the effects of these traditional food products, which are currently produced commercially in Japan.     

Isolation and characterization of <Emphasis Type="Italic">Bacillus</Emphasis><Emphasis Type="Italic">polyfermenticus</Emphasis> isolated from <Emphasis Type="Italic">Meju,</Emphasis> Korean soybean fermentation starter

Bacteria of the Bacillus species have been reported as an important microorganism in fermented soybean products. In the present study, thirty Bacillus isolates were screened from Meju, a Korean soybean fermentation starter. The comparative analysis of 16S rDNA sequences, 16S-23S internal transcribed spacer sequences, phenotypic, and biochemical characterizations revealed three phylogenetically distinct groups namely Bacillus atrophaeus, Bacillus polyfermenticus and Bacillus subtilis. The isolates were assayed for poly-γ-glutamate production and fibrinolytic activity. Among the isolates, B. polyfermenticus exhibited maximum poly-γ-glutamate production and fibrinolytic activity. Moreover, the soybean products fermented by B. polyfermenticus have increased the time taken for coagulation and hemorrhage in mice. The results of the present study clearly indicate the functional role of B. polyfermenticus in fermented soybean products.     

传统大豆发酵食品中大豆异黄酮的生理保健机能的研究进展

大豆异黄酮属于黄酮类化合物,是一类具有重要生物活性的化合物,在大豆和传统大豆发酵食品中含量丰富。近年来研究发现大豆异黄酮在预防癌症、骨质疏松症、心血管疾病和改善妇女更年期综合症等方面具有广泛的生理活性,因此引起了国内外学者的广泛关注。大豆异黄酮的研究,不仅为功能性大豆制品的开发提供理论基础,也为人们合理的膳食提供参考。综述近年来国内外对大豆异黄酮生理保健机能的研究进展。     

New fermentation technique for complete digestion of soybean protein

The aim of this study was to develop a new fermentation method in order to improve the digestion of soybean protein, and to promote normal fermentation of soybean. A proximate composition, such as moisture, pH, and reducing sugar, of fermented soybeans by the new fermentation was similar to those of controls. Neutral protease activity, the most important factor for fermented soybean products, was the highest, having about 636 U/g at 54 h fermentation. The content of total free amino acid was almost 3-18 times higher than controls. The three-step fermented soybeans can be used as a functional food ingredient for human consumption, with higher protein digestibility.     

Concentrations of Free Sugars in Sheep Rumen Fluids

A convenient method was proposed for the estimation of glucosamine content in koji. In this method, the time of acid hydrolysis of the mold sample was markedly shortened modifying the previously reported method as follows; the mold sample was immersed in 60% of sulfuric acid for 24 hr at 25°C, and then the mixture was diluted with water to make the concentration of sulforis acid 1 n and autoclaved under the pressure at 1 kg/cm² for 1 hr. The liberated glucosamine was assayed by Blix’s method. The glucosamine contents of mycelia obtained from the submerged and surface cultures were increased about 2 times of initial stages in prolonged incubation. The significant differences of the glucosamine contents in various kojis were seen depending on the raw materials used; the values were 18~26mg/g in wheat bran koji and 6~16 mg/g in rice and defatted soybean meal koji.