酸法水解大豆异黄酮的研究

采用酸法将糖苷型大豆异黄酮水解成其苷元形式。通过正交实验得到盐酸水解大豆异黄酮的最佳反应条件为 :盐酸浓度为6mol·L-1,酸解时间为3h;酸解温度50℃ ,盐酸体积与原料比为4∶1。利用本实验获得的最适酸解条件反应 ,可使染料木苷生成染料木素的转化率达到98%以上     

In vivo metabolism of Talosin A, new isoflavonol glycoside from Kitasatospora kifunensis, in rats

The isoflavonol glycoside Talosin A, genistein (GT)-7-α-L-6-deoxy talopyranose (GT-Tal), was first isolated from the culture broth of Kitasatospora kifunensis MJM341. The aim of the present study was to evaluate the oral absorption and metabolism of the newly isolated isoflavonol glycoside, GT-Tal compared to genistin (GT-7-O-β-D-glucopyranoside; GT-Glu). Free GT-Glu and GT-Tal could not be detected prior to enzymatic hydrolysis of the corresponding conjugates in rat plasma. Following oral administration of GT-Tal (15 min), GT-Tal was rapidly absorbed through the gastrointestinal tract and metabolized into GT-Tal conjugates with a mean C_max of 2.74 µg/mL. GT-Tal was further metabolized to its aglycone, free GT and conjugated GT. After oral administration, GT-Glu was absorbed after being convereted to its aglycone and then further metabolized into its conjugate metabolites (free GT with a mean C_max of 0.24 mg/mL at 1.25 h; conjugated GT with a mean C_max of 1.31 mg/mL at 2.00 h). Significant differences in absorption and metabolism of GT-Tal and GT-Glu were observed. GT-Tal was metabolized into its corresponding conjugates or underwent deglycosylation to form GT, whereas GT-Glu was metabolized into its aglycone, GT.     

胶原纤维吸附剂对单糖基黄酮苷类化合物的层析分离性能

以戊二醛交联胶原纤维吸附剂(CFA)为填料,对两种结构相近的单糖基黄酮苷类化合物(染料木苷和黄芩苷)进行了柱层析分离。结果表明,通过改变乙醇水溶液的浓度,可以调节CFA对染料木苷和黄芩苷的吸附选择性;当CFA的用量为6 g,层析柱的高径比为10∶1时,采用100%、90%和70%乙醇水溶液进行分步洗脱,染料木苷和黄芩苷能够得到分离。分离所得染料木苷和黄芩苷的纯度分别为98%和97%,回收率分别为99.35%和96.52%。     

Inheritance of isoflavone contents in soybean seeds

Summary We studied the genetic basis of isoflavone content inheritance in soybean seeds. The progenitors BARC-8 (low isoflavone content), IAC-100 (high isoflavone content), the F₁ and F₂ populations derived from reciprocal crosses, and backcross populations were analyzed for isoflavone content and composition. Six isoflavones were detected: daidzin (DZ), genistin (GT), glycitin (GC), malonyldaidzin (MDZ), malonylgenistin (MGT) and malonylglycitin (MGC). DZ, GT, MDZ and MGT contents were influenced by the cytoplasm and the nuclear genes of the maternal parent. For this reason, a genetic model was considered that included the cytoplasmic effect and epistasis between nuclear and cytoplasmic genes. Except for GT, the additive effect was the most important one. For GT content the cytoplasmic effect was the most important. Except for MDZ, the epistatic effects were significant for all the isoflavone forms. Our data indicate that genetic improvement for these traits should explore the additive genetic variances in superior lines or the cytoplasmic effect and the epistatic interactions between cytoplasmic and nuclear genes to obtain the largest selection gains.     

Genetic parameters relating isoflavone and protein content in soybean seeds

Isoflavones are a class of compounds present in high amounts in soybean seeds, which can be used for prevention and treatment of several chronic diseases. Proteins present in soybean seeds are the basis for the high nutritional value and versatility of this leguminous species in animal and human feeding. The main goals of this work were to estimate heritabilities for isoflavone contents in soybean seeds and the correlation between isoflavone and protein contents. Commercial variety IAC-100 (high isoflavone and normal protein contents) and the line BARC-8 (low isoflavone and high protein contents) were crossed, and one single F₁ plant derived 97 F₂ seeds, which were used to obtain F₃ seeds. A sample of F₃ seeds from each F₂ plant was used for isoflavone determination by HPLC and protein by the Kjeldahl method. Six isoflavone forms were detected: daidzin, genistin, glycitin, malonyldaidzin, malonylgenistin and malonylglycitin. Total isoflavone contents ranged from 427.92 to 965.89 μg per gram of dry seed and the protein content ranged from 45.17 to 34.95% in BARC-8 and IAC-100, respectively. Our results indicate that it is possible to select for high isoflavone content in early breeding generations because the broad sense heritabilities for the contents of the various isoflavone forms were higher than 90%. In addition, high correlation values among the contents of the individual isoflavone forms were observed (between 0.80 and 0.98). However, negative correlation values were obtained between isoflavone and protein contents, ranging from −0.51 to −0.37 for the different isoflavone forms. The correlation value of −0.47 between total isoflavone and protein contents confirmed the negative correlation between these two parameters, as reported by other authors. This revised version was published online in August 2006 with corrections to the Cover Date.