Molecular mechanisms of bitterness and astringency in the oral cavity induced by soyasaponin

The interaction mechanism between soyasaponin(Ssa)and bitter receptors/mucin,as well as the saliva interface behavior of Ssa,were investigated to explore the presentation mechanism of Ssa bitterness and astringency(BA).Strong bitterness arising from high Ssa concentrations(0.5–1.5 mg/mL)had a masking effect on astringency.At Ssa concentrations of 1.0–1.5 mg/mL,Ssa micelles altered the structure of mucin,exposing its internal tryptophan to a more polar environment.At Ssa concentrations of 0.05–1.50 mg/mL,its reaction with mucin increased the aggregation of particles in artificial saliva,which reduced the frictional lubricating properties of oral saliva.Ssa-mucin interactions affected the salivary interfacial adsorption layer,and their complexes synergistically reduced the interfacial tension.Ssa monomers and soyasapogenols bind to bitter receptors/mucin via hydrogen bonding and hydrophobic interactions.Class A Ssa binds more strongly than class B Ssa,and thus likely presents a higher BA.In conclusion,Ssa interacts with bitter receptors/mucin causing conformational changes and aggregation of salivary mucin,resulting in diminished frictional lubricating properties of oral saliva.This,in turn,affects taste perception and gustatory transmission.

Evaluating effects of gypenosides and soyasaponins on differentiation of neural stem cells as an in vitro model

Neural stem cell has a potential to differentiate into neurons, astrocytes and oligodendrocytes. It provides an in vitro model to screen herbal medicines on the cellular differentiation and development level. In this work, active component from gypenosides and soyasaponins was prepared to investigate their effects on the differentiation of neural stem cells.. Both gypenosides and soyasaponins promote the differentiation of neural stem cells. This method provides speed and practicality for screening effective herbal medicine. It is well suited for studying the mechanism of cell differentiation and development.

Identification of QTLs Associated with Total Soyasaponin Content in Soybean (Glycine max (L.) Merr.)

Soyasaponins are valuable compounds in certain drugs, industry, food additives and surfactants. Selecting cultivars with higher-soyasaponin content along with agronomic traits is a main goal for many soybean breeders. The aim of the present study was to identify the quantitative trait loci （QTLs） associated with total soyasaponin content through a F2 population, which was derived from a cross between Ha 91016 （higher soyasaponin content cultivar, 16.8 mg gl） and N98-9445A （lower soyasaponin content, only 5.7 mg g-l）. A genetic linkage map including a total of 162 simple sequence repeat markers was constructed, which covered the total length 2 735.5 cM, and the average distance between markers was 16.96 cM. Two QTLs associated with total soyasaponin content were identified. One, qSAP1 （located in sat_044-satt102 of linkage group （LG） K）, could explain 12.6% of phenotypic variance. The other, qSAP_2, was located between satt368 and sat413 of LG Dla, which could explain 15.8% of phenotypic variance. It was concluded that the two QTLs would have some potential value for marker-assisted selection for high-soyasaponin content breeding in soybeans.

皂苷类似物与肾素的分子对接和结合能分析

肾素是治疗高血压疾病的重要靶标之一,对肾素抑制剂大豆皂苷I及其类似物大豆皂苷II、甘草皂苷、单葡萄糖醛酸甘草皂苷元与肾素进行分子对接,采用分子动力学模拟和MMPBSA相结合的方法计算对接复合物的结合自由能,并且对各部分贡献能以及分子间相互作用进行分析。结果表明范德华力和静电相互作用是复合物形成的主要驱动力,S2和S3是肾素和皂苷相互作用重要的活性口袋,Ala229、Asp38、Asp226、Gly228和Tyr83是肾素中与这类抑制剂形成疏水作用的重要氨基酸残基,Ser230、Tyr231、Ser84则可与抑制剂形成氢键。对接结果与皂苷抑制能力吻合性较好,可为新的肾素抑制剂的发现奠定基础。

大豆皂苷Ⅰ抑制唾液酸转移酶的分子机理研究

从晶体结构出发,应用分子对接和结合自由能分析,研究了唾液酸转移酶(Sialyltransferase,ST)与其抑制剂大豆皂苷Ⅰ的相互作用机理,确定了它们的作用位点、作用力类型及大小。结果表明:范德华力和静电相互作用是复合物形成的主要驱动力,极性溶剂化能则起相反作用;8个氨基酸残基Gly149、Ser151、Met172、Asn173、Phe292、Trp300、His301、Ser325与大豆皂苷Ⅰ形成疏水相互作用,11个氨基酸残基Asn150、Tyr194、Ser271、Thr272、Gly273、Ile274、Gly291、Gly293、His302、Glu305、Glu324与大豆皂苷Ⅰ形成氢键作用;大豆皂苷Ⅰ占据了ST与底物胞苷一磷酸-β-N-乙酰神经氨酸相互作用的12个氨基酸残基中的11个,可起到竞争性抑制的作用。

A recently evolved BAHD acetyltransferase,responsible for bitter soyasaponin A production,is indispensable for soybean seed germination

Soyasaponins are major small molecules that accumulate in soybean(Glycine max)seeds.Among them,type-A soyasaponins,fully acetylated at the terminal sugar of their C22 sugar chain,are responsible for the bitter taste of soybean-derived foods.However,the molecular basis for the acetylation of type-A soyasaponins remains unclear.Here,we identify and characterize Gm SSAc T1,encoding a BADH-type soyasaponin acetyltransferase that catalyzes three or four consecutive acetylations on type-A soyasaponins in vitro and in planta.Phylogenetic analysis and biochemical assays suggest that Gm SSAc T1 likely evolved from acyltransferases present in leguminous plants involved in isoflavonoid acylation.Loss-of-function mutants of Gm SSAc T1 exhibited impaired seed germination,which attribute to the excessive accumulation of null-acetylated type-A soyasaponins.We conclude that Gm SSAc T1 not only functions as a detoxification gene for high accumulation of type-A soyasaponins in soybean seeds but is also a promising target for breeding new soybean varieties with lower bitter soyasaponin content.

大豆皂苷专利技术综述

本文从专利技术的角度,概述了大豆皂苷的提取和应用情况。大豆皂苷的制备方法有基本固定的工艺流程,继续研发的空间有限,而大豆皂苷作为功能活性成分,在医药、食品、日用品等领域应用广泛,尤其在医药领域,大豆皂苷能够预防或治疗多种疾病,表现出强大的发展潜力。本文旨在为大豆皂苷今后的技术发展提供一定的借鉴作用。

腹腔注射大豆皂甙在脑和外周组织中的分布

采用１２５Ｉ标记大豆皂甙，观察了腹腔注射放射性示踪大豆皂甙在大鼠体内和脑内的分布。结果表明：大鼠腹腔内注入放射性大豆皂甙３０ｍｉｎ后，脑和外周组织器官中浓度达到高峰，其中含量较高的组织是脑和肾上腺，在脑中含量最高的区域是下丘脑。证明了外周给予大豆皂甙可以通过血脑屏障进入脑组织，并支持大豆皂甙作用于下丘脑、参与中枢心血管调节的观点；还发现大豆皂甙对肾上腺有很高的亲合性，很可能同时具有外周心血管调节作用。