银杏落叶化学成分研究

采用硅胶与Sephadex LH-20柱色谱等手段从银杏落叶中分离得到22个化合物,通过理化性质和波谱数据分别鉴定为白果醇(1)、二十八烷酸(2)、棕榈酸(3)、三十七烷(4)、二十四烷(5)、4,10-二十九烷二醇(6)、β-谷甾醇(7)、胡萝卜苷(8)、银杏内酯A(9)、银杏内酯B(10)、银杏内酯C(11)、白果内酯(12)、对羟基苯甲酸(13)、莽草酸(14)、芫花素(15)、芹菜素(16)、银杏素(17)、异银杏素(18)、金松双黄酮(19)、白果黄素(20)、芦丁(21)和甘露醇(22),其中化合物2、4～6和22为首次从该种植物中分离得到,这些研究为银杏落叶及银杏资源的综合利用奠定了基础。     

银杏外种皮中银杏酚酸的分离和抑菌试验

本文介绍了用薄层层析分离银杏外种皮中银杏酚酸的方法,分离得到白果酸和氢化白果酸,经抑菌试验表明,两种物质都有较强的抑制真菌的效果,并且白果酸比氢化白果酸的抑菌效果好。     

银杏外种皮研究进展

银杏(GinkgobilobaL.)为银杏科银杏属多年生落叶乔木,又名白果,是我国特有树种,也是世界上珍贵的药用植物资源。对银杏叶和果的研究,尤其是对银杏叶黄酮的研究,已取得了多项成果〔1,2〕,但对银杏外种皮的研究还不多。银杏外种皮是种子硬壳外面的肉质部分,长期以来,被视为废物丢弃,既浪费资源又污染环境。国内自90年代末,扬州大学、中国药科大学等单位开展了银杏外种皮研究工作,但目前还没有规模生产的产品投向市场〔3〕。笔者在综合检索的基础上对银杏外种皮研究工作作一综述,希望引起对银杏外种皮开发利用工作的广泛重视。1　资源状况目前…     

银杏外种皮中银杏酸的分离方法

本文简单介绍了一种从银杏外种皮中分离银杏酸的方法,使用了皂化和酯化反应为后的两次柱层析分离提供便利条件。     

显齿蛇葡萄（藤茶）化学成分研究

从显齿蛇针萄的乙酸乙酯提取中分离得到９个化合物,经波谱分析,化学分析及与已知化事物对照,分别鉴定为;棕榈酸（１）,β－谷甾醇（２）,大黄素（３）,没食子酸甲酯（４）,槲皮素（５）,槲皮素－３－０－β－Ｄ葡萄糖甙（６）,花旗松素（７）,洋芹菜（８）和蛇葡萄素（９）。９个化合物无为首次从该植物中分离得到。     

银杏种核的多样性

银杏属于银杏科单属单种的植物，这在植物界中少有。目前，全世界５０多个国家和地区的银杏都是从中国和日本引种去的。我国银杏种植面积已达１２．３万公顷，栽植株数达１２亿株，银杏种核（白果）年产量约７０００吨。众所周知，银杏的寿命可达上千年，实生树的始种期为１０—２０年，嫁接树的始种期为５—７年。银杏种核（去掉种子外种皮）的大小和形状各异。根据笔者收集到的实物，谈谈银杏种核的生物多样性。作为单属种的银杏，其种核大小与形状应无太大变化，然而却不然，请看：银杏种核单粒重最大的为‘喜干’（产于日本），单粒重为…     

长管假茉莉的化学成分

从药用植物长管假茉莉（Ｃｌｅｒｏｄｅｎｄｒｕｍｉｎｄｉｃｕｍ）中分离鉴定了８个化合物,通过波谱分析及已知数据对照,分别鉴定为３,４－二羟基苯乙醇（３,４－ｄｉｈｙｄｒｏｘｙｐｈｅｎｙｌｅｔｈａｒｏｌ,１）,粗毛豚草素（ｈｉｓｐｉｄｕｌｉｎ,２）粗毛豚鼠素葡萄糖醛酸苷（ｈｉｓｐｄｕｌｉｎ７－Ｏ－ｇｌｕｃｕｒｏｎｉｄｅ,３）泽兰叶黄素（ｅｕｐａｆｏｌｉｎ,４）黄芩素苷（ｓｅｃｕｔｅｌｌａｒｅｉｎ,５）     

显齿蛇葡萄(藤茶)化学成分研究

从显齿蛇葡萄的乙酸乙酯提取物中分离得到9个化合物,经波谱分析、化学分析及与已知化合物对照,分别鉴定为：棕桐酸（1）、β－谷甾醇（2）、大黄素（3）、没食子酸甲酯（4）、槲皮素（5）、槲皮素－3－0－β－D－葡萄糖甙（6）、花旗松素（7）、洋芹素（8）和蛇葡萄素（9）。9个化合物均为首次从该植物中分离得到。     

银杏外种皮对钉螺的杀灭机理

银杏外种皮是银杏加工过程中的废弃物,人们很早就将其干燥后粉碎用于抗菌、杀虫(Isao,1986),杨小明等(2004)还发现其具有显著的抗肿瘤效果。为进一步挖掘银杏外种皮的价值,我们以石油醚为溶剂提取银杏外种皮后得到一种淡黄色物质(其主要成分为银杏酸),将其命名为银杏外种皮石油     

银杏中种皮化学成分的分离及鉴定

银杏（Ginkgo biloba Linn．）在中国种植广泛,其产量占全世界总产量的70％[1]。中药白果仁是银杏种子去除肉质外种皮和骨质中种皮后得到的,具有敛肺定喘、止带缩尿的功效。目前,有关银杏种子的研究主要集中在具有药食同源的白果仁[2]及具有潜在应用价值的外种皮[3]上,鲜见对银杏种子中种皮的研究报道。生产中大量的银杏中种皮被废弃,因此,开展银杏中种皮的相关研究对于充分利用该类资源非常必要。鉴于此,作者对银杏中种皮的化学成分进行了系统分析,以期为其开发应用提供参考依据。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Synthesis and antimicrobial studies of hydrazone derivatives of 4-[3-(2,4-difluorophenyl)-4-formyl-1H-pyrazol-1-yl]benzoic acid and 4-[3-(3,4-difluorophenyl)-4-formyl-1H-pyrazol-1-yl]benzoic acid

Microbial resistance to antibiotics is an unresolved global concern, which needs urgent and coordinated action. One of the guidelines of the Centers for Disease Control and Preventions (CDC) to combat antibiotic resistance is the development of new antibiotics to treat drug-resistant bacteria. In our effort to find new antibiotics, we report the synthesis and antimicrobial studies of 30 new pyrazole derivatives. These novel molecules have been synthesized by using readily available starting materials and benign reaction conditions. Some of these molecules have shown activity with MIC values as low as 0.78?µg/mL against four bacterial strains; Staphylococcus aureus, methicillin-resistant S. aureus, Bacillus subtilis, and Acinetobacter baumannii. Furthermore, active molecules are non-toxic to mammalian cell line.

     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.