大豆异黄酮糖苷和苷元免疫功能研究

用大豆异黄酮糖苷和大豆异黄酮苷元喂养小鼠后,其鸡红细胞作免疫原的溶血素光密度值比在相同环境下空白对照组明显增加,这表明大豆异黄酮糖苷和苷元都能有效提高小鼠体液免疫功能;同时发现小鼠对大豆异黄酮苷元吸收效果强于大豆异黄酮糖苷,说明大豆异黄酮苷元免疫功能优于大豆异黄酮糖苷。     

丹贝异黄酮生物活性增强的机理研究

以少孢根霉RT-3孢子接种在含高浓度的大豆异黄酮提取物制成的发酵基质中，发酵36h后大豆异黄酮被部分水解成相应的苷元．用从丹贝中分离的β-葡萄糖苷酶与标准品染料木素糖苷和大豆苷元的糖苷作用10min，染料木素糖苷和大豆苷元的糖苷被水解成相应的苷元．结果表明：丹贝异黄酮生物活性增强是发酵剂RT-3孢子分泌的β-葡萄糖苷酶将异黄酮由糖苷水解成苷元，而苷元比糖苷有更强的活性．     

大豆异黄酮糖苷及其苷元调节免疫功能的比较研究

目的:比较大豆异黄酮糖苷及游离型大豆苷元对小鼠免疫功能能力的影响。方法:将实验室提取大豆异黄酮糖苷和苷元(纯度为41%左右)的产品按照40～100mg/kg,连续灌胃21d后,与对照组相比能显著提高小鼠腹腔巨噬细胞的吞噬能力及小鼠脾重。结果:大豆异黄酮糖苷和苷元具有较强的调节小鼠腹腔巨噬细胞的吞噬能力,能刺激小鼠脾脏和胸腺器官的发育;同一剂量的大豆异黄酮糖苷和苷元雌鼠的效果要好于雄鼠,游离型大豆苷元的吸收效果明显好于糖苷。     

豆制品中大豆异黄酮转化与富集的研究进展

大豆异黄酮属于黄酮类化合物，主要分为结合型大豆异黄酮糖苷和游离型大豆异黄酮苷元。游离型大豆异黄酮苷元具有比结合型大豆异黄酮糖苷更高的生理活性，如预防骨质疏松和女性更年期综合症，抗氧化和抗癌抑癌等。大豆异黄酮在食品保健方面应用前景广阔，国内外研究者对大豆异黄酮研究越发深入。该文主要综述豆制品中大豆异黄酮的转化和富集方法，旨在为生产富含大豆异黄酮苷元的功能性豆制品研究提供参考。     

保健食品中大豆异黄酮含量的高效液相色谱法测定

采用高效液相色谱法,对市场上销售的5种国产和进口大豆异黄酮保健食品中12种大豆异黄酮的含量进行测定.对3种苷元大豆素、黄豆素和染料木素,3种糖苷大豆苷、黄豆苷、染料木苷采用各自的标准品绘制标准曲线用内标法进行定量,对乙酰化或丙二酰化糖苷用对应糖苷的内标响应因子和转换因子来计算含量.结果表明,大豆异黄酮保健食品的质量参差不齐,存在着含量标示不准确的问题,甚至部分完全不含有大豆异黄酮,亟待加强对大豆异黄酮保健食品的市场监管.     

大豆胚轴中异黄酮的提取及其抗血小板聚集作用的研究

从大豆胚轴提取总糖苷后，采用C18反相柱层析法分离大豆异黄酮糖苷，再将其水解制备成异黄酮苷元，并研究大豆异黄酮对人血小板聚集性的影响。结果：在体外人血小板聚集实验中，大豆异黄酮苷元均抑制ADP、胶原蛋白和肾上腺素诱导的血小板聚集。提示：大豆异黄酮可能有助于防止血栓形成。     

高效液相色谱法快速测定大豆异黄酮制品中有效成分的研究

采用高效液相色谱法测定大豆异黄酮制品中染料木苷、黄豆苷、染料木黄酮和黄豆苷元含量.固定相为Agilent-1100 C18柱(3.9 x 150mm);以甲醇:水=35%～45%为流动相,进行梯度洗脱,流速为1.0～2.0mL/min;柱温为室温;检测波长为260nm.实验结果表明,市售30%大豆异黄酮制品中,含大豆异黄酮糖苷近28%,其中染料木苷为4%、黄豆苷为8%,苷元形式异黄酮未检出;采用酶水解法制备的大豆异黄酮水解物中含染料木黄酮14.3%、黄豆苷元9.8%,其大豆异黄酮苷元占大豆异黄酮总含量的96%.     

纤维素酶水解大豆异黄酮糖苷混合物的抗氧化活性

大豆异黄酮主要以糖苷类型的分子形式存在于大豆中,但是其具有生物活性的部分主要是苷元.为了建立一种体外生物转化大豆异黄酮糖苷为大豆异黄酮苷元的新方法,采用纤维素酶水解70%乙醇提取脱脂大豆粕得到的异黄酮粗提物,对比了水解前后两样品的异黄酮组成差异,并测定了其清除DPPH自由基的能力.结果表明:纤维素酶能完全水解大豆苷和染料木苷为大豆素和染料木素;而不能水解丙二酰基染料木苷和丙二酰基大豆苷.纤维素酶处理以后的大豆异黄酮糖苷混合物达到DPPH自由基50%清除率所需要的异黄酮浓度是未处理的大豆异黄酮糖苷混合物的1/2.56.     

大豆异黄酮组分在腐乳后酵过程中的变化

研究腐乳后酵过程中大豆异黄酮组成和含量的变化。结果表明：在腐乳后酵过程中,大豆异黄酮总含量呈下降趋势;当食盐含量较低时,糖苷(daidzin 和genistin)分解较快;大豆异黄酮糖苷形式(daidzin 和genistin)转化为苷元形式(daidzein 和genistein)。说明腐乳后酵有效提高了大豆异黄酮的生物活性。     

青方腐乳发酵过程中大豆异黄酮的转化研究

本文比较了青方、红方、白方和低盐红腐乳中大豆异黄酮组成和含量差异,并对青方腐乳发酵过程中大豆异黄酮含量和构型变化规律进行研究。结果表明,四种类型腐乳中大豆异黄酮基本以苷元形式存在,青方腐乳大豆异黄酮含量明显低于其他类型腐乳,仅为红方腐乳的33.01%,从单一异黄酮来看,大豆苷元和染料木素在四种类型腐乳中的含量明显高于黄豆黄素;青方腐乳发酵过程中大豆异黄酮转化研究发现,白坯中大豆异黄酮以糖苷型为主,染料木苷含量高于大豆苷和黄豆黄苷,前酵过程中糖苷型大豆异黄酮转化为苷元型大豆异黄酮,盐腌过程中糖苷型大豆异黄酮含量有轻微降低,发酵过程中苷元型大豆异黄酮总量在后酵前30 d显著下降,其中大豆苷元可能部分转化为雌马酚,导致青方腐乳大豆异黄酮含量明显低于其他类型腐乳,对其转化物质需进一步鉴定。     

大豆异黄酮苷元的提取及其抗血浆脂蛋白氧化作用

从大豆胚轴提取总糖苷后,采用C18反相柱层析法分离大豆异黄酮糖苷,再将其水解制备成异黄酮苷元,并对大豆异黄酮苷元的抗脂蛋白氧化作用进行了实验研究.12名健康受试者空腹食用大豆异黄酮苷元前后抽取静脉血制备血浆脂蛋白,观察血浆脂蛋白过氧化程度及氧化易感性的变化.结果表明,大豆异黄酮苷元食用后受试者血浆VLDL、LDL和HDL过氧化脂质水平明显降低;在体外进行氧化修饰时,LDL氧化延滞时间明显延长,LDL氧化易感性下降.大豆异黄酮苷元可增强血浆抗氧化能力,尤其增强LDL抗氧化修饰能力,因此能够起到防治心血管疾病的积极作用.     

Hydrolysis of soybean isoflavone glycosides by a thermostable β-glucosidase from Paecilomycesthermophila

The β-glucosidase from Paecilomyces thermophila J18 was found to be capable of hydrolysing daidzin and genistin in a previous study. This report further evaluated the thermostability and hydrolysis of soybean isoflavone glycosides. The enzyme was found to be very stable at 50 °C, and retained more than 95% of its initial activity after 8 h at 50 °C. It converted isoflavone glycosides, in soybean flour extract and soybean embryo extract, to their aglycones, resulting in more than 93% of hydrolysis of three isoflavone glycosides (namely, daidzin, genistin and glycitin) after 4 h of incubation. Also, addition of the β-glucosidase greatly increased the contents of isoflavone aglycones in the suspended soybean flour and soymilk. The results indicate that the thermostable β-glucosidase may be used to increase the isoflavone aglycones in soy products. This is the first report on the potential application of fungal β-glucosidases for converting isoflavone glycosides to their aglycones in soy products.     

Effect of soybean varieties on the content and composition of isoflavone in rice-koji miso

To clarify the effect of soybean varieties on isoflavone, a useful component for human health, in soybean products, we investigated changes in the isoflavone content and composition in rice-koji miso, after fermentation/aging for 6 or 12 months using varieties of soybeans (Tohoku-126, Tohoku-135, Tohoku-139, Suzuyutaka and Chinese soybeans), by high performance liquid chromatography. In soybeans, the total isoflavone content in Tohoku-126 was 444 mg/100 g, which was 1.2–2.0 times the content in the other soybean varieties. The malonyl glycosides and aglycones in soybeans accounted for more than 60% and only a few percent, respectively. As for rice-koji miso, the total isoflavone and aglycone contents were the highest in miso prepared from Tohoku-126. The ratios of glycosides to aglycones (80.1–92.6%) in miso were higher than those in the original soybeans. The time course of the isoflavone composition during the fermentation/aging process of rice-koji miso indicated that glycosides decreased from 86.4% to 44.9% after 6 months but aglycones increased from 9.6% to 53.3%.     

Biotransformation of isoflavone glycosides by Bifidobacterium animalis in soymilk supplemented with skim milk powder

ABSTRACT:  Two probiotic strains, Bifidobacterium animalis A and B, were used for the biotransformation of isoflavone glycosides in soymilk prepared from soy protein isolate (SPI) supplemented with skim milk powder (SMP) (SSMP). Unsupplemented soymilk (USM) and reconstituted skim milk powder (RSMP) were used as controls. The numbers of viable microorganisms in these products were enumerated. Lactose and isoflavone contents were quantified using high-performance liquid chromatography (HPLC). Our results showed that there was significantly higher biotransformation of isoflavone glycosides to aglycones in SSMP than that in USM. The levels of biotransformation were 83.96% and 85.43% for B. animalis A and B, respectively, compared to 74.30% and 72.82% for the USM. In addition, lactose utilization by both strains in SSMP was also higher than that in RSMP. At 24 h, 21.16 mg/mL of lactose was utilized in SSMP by B. animalis A compared with that of 16.88 mg/mL in RSMP. Consequently, the pH of SSMP was lower (3.80) than RSMP (4.00). However, the number of viable bacteria in SSMP was slightly lower than that in RSMP but significantly higher than that in USM. It appears that SMP enhanced the biotransformation of isoflavone glycosides to aglycones and SPI increased the lactose utilization by B. animalis A and B.     

Production of beta-glucosidase and hydrolysis of isoflavone phytoestrogens by Lactobacillus acidophilus, Bifidobacterium lactis, and Lactobacillus casei in soymilk

ABSTRACT:  The study determined β-glucosidase activity of commercial probiotic organisms for hydrolysis of isoflavone to aglycones in fermenting soymilk. Soymilk made with soy protein isolate (SPI) was fermented with Lactobacillus acidophilus LAFTI^® L10, Bifidobacterium lactis LAFTI^® B94, and Lactobacillus casei LAFTI^® L26 at 37 °C for 48 h and the fermented soymilk was stored for 28 d at 4 °C. β-Glucosidase activity of organisms was determined using ρ-nitrophenyl β-D-glucopyranoside as a substrate and the hydrolysis of isoflavone glycosides to aglycones by these organisms was carried out. The highest level of growth occurred at 12 h for L. casei L26, 24 h for B. lactis B94, and 36 h for L. acidophilus L10 during fermentation in soymilk. Survival after storage at 4 °C for 28 d was 20%, 15%, and 11% greater ( P < 0.05) than initial cell counts, respectively. All the bacteria produced β-glucosidase, which hydrolyzed isoflavone β-glycosides to isoflavone aglycones. The decrease in the concentration of β-glycosides and the increase in the concentration of aglycones were significant ( P < 0.05) in the fermented soymilk. Increased isoflavone aglycone content in fermented soymilk is likely to improve the biological functionality of soymilk.     

The influence of isoflavone glycosides on the taste of subterranean clover leaves

Four variants of subterranean clover cultivar Geraldton were fed to sheep. One variant, whose flavonoid glycosides were stable due to absence of glucosidase activity in the leaves, was more distasteful to the sheep than were the other clovers. These results suggest that flavonoid glycosides may be unpalatable to the sheep whilst the products of hydrolysis (glucose and aglycone) are not. Taste testing by human subjects of seven purified isoflavone glycosides indicated a slight but distinctive astringent–bitter taste in contrast to the lack of taste of the aglycones.     

丹贝异黄酮的提取分离与结构鉴定

从丹贝中分离纯化了 3种异黄酮 ,它们分别是染料木素、大豆黄素、黄豆黄素 ,而未分离到 6 ,7,4’ -三羟基异黄酮。丹贝中异黄酮的组成主要是各种苷元 ,证明丹贝生物活性的提高是由于异黄酮由糖苷水解成苷元所致。同时还发现 ,使用甲醇作溶剂在分离纯化过程中可能使染料木素转变成黄豆黄素     

添加微量元素对黑豆发芽过程中成分的影响

目的:研究微量元素对黑豆发芽过程中成分变化的影响。方法:采用HPLC法对添加一定量微量元素Zn、Mn、Cu、Fe发芽的黑豆中大豆苷、染料木苷、大豆苷元和染料木素进行含量测定;采用紫外分光光度法对黑豆中总黄酮的含量进行测定;采用高效凝胶过滤色谱法对肽分子量分布进行测定;采用比色法对多肽、游离氨基酸和植酸进行含量测定;采用火焰原子吸收光谱法、电感耦合等离子体原子发射光谱法对微量元素进行含量测定。结果表明:添加微量元素对黑豆发芽过程中成分影响较明显,最终选定的微量元素浓度为:硫酸锌30 mg/L、硫酸锰20 mg/L、硫酸铜10 mg/L、硫酸亚铁20 mg/L。通过定量分析,黑豆添加微量元素发芽与清水发芽的黑豆16 d相比,异黄酮苷元增长了88.24%;游离氨基增加了87.29%;植酸含量则减少了30.86%。结论:黑豆添加微量元素发芽有利于异黄酮苷元、游离氨基酸等营养成分的生成,营养价值更高。     

A New Simplified and Stability Indicating Liquid Chromatography Method for Routine Analysis of Isoflavones Aglycones in Different Complex Matrices

In this work, a stability indicating method for routine analysis of isoflavones in different matrices was developed and validated. In order to simplify the analytical method, the glycosides were previously hydrolyzed to the corresponding aglycone forms. The separation of all isoflavone aglycones was achieved in 23 min, with a total time of analysis of 30 min, using trifluoroacetic acid 0.1 % (v/v) and acetonitrile:trifluoroacetic acid (100:0.01, v/v) as mobile phase. The LC method specificity was evaluated by the analysis of isoflavone standards submitted to acidic, alkali, neutral, oxidative, and photolytic stress conditions. The isoflavones degraded in alkali at 60 °C or in alkali under ulraviolet C (UVC) radiation, forming, in both conditions, three degradation products D1, D2, and D3 which were analyzed by liquid chromatography mass spectroscopy (LC-MS/MS). The method showed linearity higher than 0.999 with the concentration ranged from 0.1 to 10 μg ml^-1 for all isoflavone aglycones. The limits of quantitation obtained using calibration curves were from 0.28 to 0.37 μg ml^-1 and the intermediary precision at three levels (2, 6, and 10 μg ml^-1) showed RSD values between 0.03 and 0.25 %. After the performed validation, the LC method was applied to compare the isoflavone aglycones content in three different matrices: Glycine max beans, Glycine max dry extract, and isoflavone aglycone loaded nanoemulsion. The repeatability data showed RSD values between 0.02 and 1.41 % and the intermediary precision at three levels showed RSD values between 0.05 and 1.99 %. The recovery data of the isoflavone aglycones standards in the matrices at three levels were between 90.74 and 106.43 %.