Structure of oligomeric proanthocyanidines from <Emphasis Type="Italic">Hedysarum thienum</Emphasis> roots studied by thiolysis and MALDI-TOF MS

Oligomeric proanthocyanidines from Hedysarum theinum roots that were cleaved by benzylmercaptan were shown to be heterogeneous mixtures consisting of prodelphinine and procyanidine structural units with the former dominating. Fractionation of oligomeric proanthocyanidines on polyamide and MCI gel CHP20P sorbent isolated fractions containing primarily mixtures of di- and trimeric, tri- and tetrameric, or tetra- and pentameric proanthocyanidines. Analysis by mass spectrometry (MALDI-TOF) showed that fractions of trimers and tetramers contained more proanthocyanidines with a single A-type bond than fractions of dimers and trimers. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 30–36, January–February, 2009.     

沙棘叶水溶性多糖SJ21的研究

热水提取乙醇沉淀获得沙棘叶粗多糖，经酸性乙醇分级和DEAE-SephadexA-25纯化得多糖SJ21．纯度鉴定表明多糖SJ21为均一多糖，分子量约为70KD．单糖组成为Xyl、Ara、Man、Gal、Glc．摩尔比为1．0：2．1：5．3：3．7：2．9．多糖SJ21结构分析采用了UV、IR、高碘酸氧化、Smith降解、甲基化分析、GC、GC-MS和NMR等方法．结果表明：多糖SJ21主链由β-（1→4）Man基、β-（1→6）Gal基、β-（1→4）Glc基构成，其中Man在6-O处有分枝；Gal在3-O处和4-O处有分枝；支链由（1→4）、（1→3）Xyl基和（1→4）或（1→5）Ara基和（1→2、4）或（1→2、5）Ara；末端基为Glc、Gal、Ara．沙棘多糖SJ21是一新结构多糖，为首次从该植物中分离得到．     

多环芳烃致癌活性的支持向量机分类模型

采用留一交叉校验法,分别用支持向量分类法、反向传播人工神经网络和K最近邻法对72个多环芳烃类化合物致癌活性构建分类模型,并作比较.其错分样本数及预报准确率分别为：7、28和22个;90.28%、61.11%和69.44%.实验结果表明,支持向量机算法具有较强的稳健性和较好的鲁棒性,能够用于多环芳烃致癌活性的分类和预测.     

Phytochemical screening and metabolomic approach based on Fourier transform infrared (FTIR): Identification of α-amylase inhibitor metabolites in Vernonia amygdalina leaves

ContextVernonia amygdalina has been reported as a potential antidiabetic agent. One of the mechanisms in diabetes mellitus treatment is the inhibition of the α-amylase enzyme’s action.ObjectiveThis study is aimed to identify the presence of secondary metabolites in Vernonia amygdalina leaf extract, which has the potential as α-amylase inhibitors through phytochemical screening combined with metabolomic analysis.Materials and methodsMethanol extract from Vernonia amygdalina leaf was partitioned into n-hexane, dichloromethane (DCM), and ethyl acetate. From this process, methanol, hexane, DCM, and ethyl acetate extracts were obtained. These extracts were then being tested for phytochemical screening, α-amylase inhibition, and FTIR. Then FTIR data were used for metabolomic analysis (PCA and PLS).ResultsThe results of the α-amylase inhibition test showed that the ethyl acetate extract had the smallest IC50 average value, which was 3.00 μg/mL. Based on the phytochemical screening test results, the extract showed positive for the presence of compounds such as flavonoids, phenols, tannins, alkaloids, and saponins. From the PCA analysis (Bi-plot), the wavenumbers that were influential in the ethyl acetate extract were 1436 to 1681 and 3341 to 3348 cm^?1. In theory, functional groups such as CH, CC, CO, NH, and OH appeared on the absorption. From the PLS analysis, these wavenumbers affected the activity.ConclusionThe most potential extract as an α-amylase inhibitor was the ethyl acetate extract. Based on phytochemical screening tests and metabolomic analysis, it was proven that this extract contained compounds as hypoglycemic agents.     

Dynamics of three-body half collisions: Ultraviolet and visible photodissociation of s-tetrazine

Ultraviolet (266 nm) and visible (532 nm) photodissociation of collision-free s-tetrazine show asymmetric dynamics with production of one translationally cool and one translationally hot HCN molecule. Furthermore, visible and ultraviolet dynamics are nearly identical, arguing that two-photon excitation is necessary for photodissociation in the visible.     

沙生植物花棒气孔导度的周期波动

研究了沙漠地区典型的高温低温条件下，沙生植物花棒的气体交换特征。结果表明，花椿叶片气孔导度日变化呈现为周期波动曲线粒体其波动周期除中午外均为２ｈ，在１９：００时后波动消失。与气孔导率波动变化相对应，净光合速率和蒸腾速率也同步地呈现周期波动，但蒸腾速度周期波动起始时间滞后于气孔导度与光合速率的起始时间。     

蒙古高原岩黄芪属（Hedysarum）植物的分类学研究

确认了蒙古高原岩黄芪属植物１９种、３变种；合并了《内蒙古植物志）第二版中的ＨｅｄｙｓａｒｕｍｆｒｕｔｉｃｏｓｕｍＰａｌｌ．和Ｈ．ｍｏｎｇｏｌｉｃｕｍＴｕｒｃｚ．、Ｈ．ｆｒｕｔｉｃｏｓｕｍＰａｌｌ．ｖａｒ．ｌｉｇｎｏｓｕｍ（Ｔｒａｕｔｖ．）Ｋｉｔａｇ．和Ｈ．ｌｅａｖｅＭａｘｉｍ；发现了一新变种Ｈ．ｆｒｕｔｉｃｏｓｕｍＰａｌｌ．ｖａｒ．ｇｏｂｉｃｕｍＹ．Ｚ．Ｚｈａｏｅｔａｌ，否定了变种Ｈ．ｓｃｏｐａｒｉｕｍＦｉｓｃｈ．ｅｔＭｅｙ．ｖａｒ．ａｒｂｕｓｃｕｌａ（Ｍａｘｉｍ．）Ｙａｋｏｖｌ．和Ｈ．ｇｍｅｌｉｎｉｉＬｅｄｅｂ．ｖａｒ．ｌｉｎｅｉｆｏｒｍｅＨ．Ｃ．Ｆｕ的存在；订正了《内蒙古植物志》第二版中的Ｈ．ｐｏｌｙｂｏｔｒｙｓＨａｎｄ．－Ｍａｚｚ．为Ｈ．ｖｉｃｉｏｉｄｅｓＴｕｒｃｚ，并重新组合其毛果变种为Ｈ．ｖｉｃｉｏｉｄｅｓＴｕｒｃｚ．ｖａｒ．ａｌａｓｃｈａｎｉｃｕｍ（Ｂ．Ｆｅｄｔｓｃｈ．）Ｙ．Ｚ．Ｚｈａｏｅｔａｌ；比《内蒙古植物志》第二版增加了Ｈ．ｄａｈｕｒｉｃｕｍＴｕｒｃｚ．ｅｘＢ．Ｆｅｄｔｓｃｈ．和Ｈ．ｓｅｔｉｇｅｒｕｍＴｕｒｂｚ．两个种；更正了《内蒙古植物志》第二版中一些种的不确切分布．     

紫草科四种植物茎叶解剖结构的比较研究

观察比较了紫草科4种植物茎叶的组织结构。结果表明：4种植物茎的横切面结构相似，维管束的数量及排列的疏密成度表现出种问差异；叶的结构为表皮细胞呈单层，且上表皮细胞的体积较下表皮细胞的体积大，叶肉中通气组织发达；叶的类型除鹤虱为等面叶外，其余三种均为背腹叶。     

小麦叶片的电阻抗图谱参数对水分胁迫的响应

电阻抗图谱参数能够反映植物的基本生理信息,通过研究不同品种、生育期和水分胁迫下的小麦叶片,得到胞内电阻、胞外电阻、弛豫时间和弛豫时间分布系数等膜参数的变化特征.通过盆栽实验,测定了分属于旱地、水地和水旱兼用型3个不同抗旱类型的7个品种的小麦叶片在抽穗期、开花期和灌浆期3个生育期,以及适宜水分、中度干旱和严重干旱3个水分条件下的电阻和电抗,应用LEVM软件拟合出相应的电阻抗图谱参数,并分析了参数的变化特征.电阻抗图谱参数与不同小麦品种的抗旱性强弱没有明显的对应关系,水分胁迫使叶片的胞外、胞内电阻和弛豫时间分布系数增大,弛豫时间减小.不同生育期对胞外、胞内电阻和弛豫时间的影响表现为:开花期＞抽穗期＞灌浆期;对弛豫时间分布系数的影响则表现为:开花期＞灌浆期＞抽穗期.电阻抗图谱参数尚不能用于表征小麦品种的抗旱性强弱,但可以提供不同生育期小麦叶片在水分胁迫下细胞膜变化的电学信息.     

福建几种主要品种茶树鲜叶矿质元素含量

研究了福建几种主要品种茶树鲜叶中１８种矿质元素含量的数量级范围,大小顺序,（Ｋ〉Ｐ,Ｃａ,Ｍｇ〉ｌ,Ｎａ〉Ｍｎ,Ｆｅ〉Ｚｎ,Ｃｕ〉Ｓｒ,Ｂａ〉Ｎｉ,Ｔｉ〉Ｃｏ,Ｃｒ,Ｌａ〉Ｖ）,及其鲜叶中某些元素（如Ｃａ与Ｍｇ与Ｆｅ,Ｃｕ与Ｚｎ,Ｓｒ与Ｂａ）含量之间的相似性,除Ｋ,Ｎａ,Ｃｒ,Ｔｉ外,鲜叶中Ｃａ,Ｍｇ,Ｐ,Ａｌ,ｃＵ,Ｚｎ,Ｆｅ,Ｍｎ,Ｂａ,ＳＲ,Ｎｉ,Ｃｏ,Ｖ,Ｌａ的含量在茶树品种间差异显著,这