银杏外种皮提取物对病原菌﹙Cylindrocladium colhounii﹚的抑制作用

采用菌丝生长抑制法,研究了银杏外种皮3种不同提取物对病原菌（Cylindrocladium colhounii）的抑制作用并测定了这些提取物的MIC/MBC。结果表明,在相同实验天数内,抑菌效果（最小抑菌率）由高到低依次为银杏外种皮乙醇提取物（37.4%）、石油醚提取物（23.7%）和新鲜外种皮汁液（18.4%）。当提取物的浓度提升到一定程度时,三者的抑菌率均可达到100%;三种提取物的MIC/MBC分别为：86.25/86.25,172.5/276,293.25/345 mg·mL^-1。可见银杏外种皮具有明显抑制该病原菌生长的作用,且抑菌成分在乙醇中的溶解度较大。这为进一步研究该抑菌成分乃至生物农药的开发奠定了基础。     

银杏外种皮提取物对几种蔬菜病原菌的抑制作用

以银杏外种皮提取物对几种蔬菜病原菌进行抑菌效果检测,结果表明,乙醇提取物、甲醇提取物的抑菌效果较好。乙醇提取物浓度为500 mg·mL^-1时,抑菌效果除对甘蓝黑斑病菌为88.5%外,对白菜炭疽病菌、茄子立枯病菌、茄子白绢病菌、黄瓜枯萎病菌均为100%。甲醇提取物浓度为500 mg·mL^-1时,对上述5种病菌的抑菌率均为100%。这为今后田间防治5种病菌及开发银杏植物源杀菌剂提供科学依据。     

银杏外种皮提取物对酪氨酸酶的抑制作用

以银杏外种皮为材料,采用水、乙醇和乙醇-乙醚三种不同的方法分离提取其中的活性物质(分别命名为1#,2#,3#),研究它们对蘑菇酪氨酸酶催化L-多巴(L-DOPA)氧化活力的影响。结果表明,这3种提取物均对蘑菇酪氨酸酶有抑制作用,1#,2#和3#对酶抑制作用的IC50分别为2.25、1.75和0.32mg/mL。抑制作用动力学结果表明:三种提取物对酶的抑制作用均表现为混合型,相应的抑制常数KI依次为2.11、1.62和0.29mg/mL;KIS依次为2.80、2.33和0.45mg/mL。结果显示,采用乙醇-乙醚提取的银杏外种皮提取物对酪氨酸酶抑制作用最强。     

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。     

银杏外种皮提取物对致病性真菌生长抑制的研究

用乙醇和石油醚分别对银杏外种皮进行回流提炼,研制出乙醇提取物和石油醚提取物,其对致病性真菌有明显抑制生长作用,抑制真菌生长有效率分别为81%和73%,抑制真菌生长效价明显优于银杏外种皮总提取物,0.5%的银杏外种皮乙醇提取物及石油醚提取物抑制真菌生长的效能相当于0.5%的克霉唑药物。     

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…     

银杏外种皮的双黄酮成分

从银杏外种皮的乙酸乙酯提取中分离得到６个化合物,其中５个经物理常数及光谱分析鉴定为金松双黄酮、银杏素、奶杏素、１－５’－甲氧基白果素及白果素。这些化合物均首次从银杏外种皮分离。     

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。     

银杏外种皮的化学成分和用途

本文介绍了银杏外种皮的现状、化学成分和用途。     

银杏外种皮提取物对芽孢杆菌生长的影响

用萃取法将银杏外种皮中的银杏酚酸成分提取出来,制成提取液。再用部分提取液乳化成乳化剂。采用液体生长抑制法和平皿培养抑制法分别对土壤中的细菌总量和芽孢杆菌进行抑菌试验。结果显示,在药浓度不断上升的情况下,相对应的细菌的存活率就越低。在液体生长抑制法中,芽孢杆菌菌悬液的OD值随药浓度的升高降低。在平皿培养法中,在药液浓度升高的情况下,土壤中细菌总量及芽孢杆菌总量受抑制程度加强。平皿培养法中用平皿表面涂布法要优于药敏纸片法。     

Development of microsatellite markers in ginkgo (Ginkgo biloba L.)

Ginkgo biloba L. is one of the oldest unevolved tree species on Earth. We isolated five polymorphic microsatellite loci from G. biloba using a dual‐suppression polymerase chain reaction technique. These loci provided microsatellite markers with high polymorphism ranging from three to 13 alleles per locus. The observed and expected heterozygosities ranged from 0.667 to 0.952 and from 0.640 to 0.897, respectively. The markers will contribute to research on the conservation, genetic diversity and mating patterns of G. biloba.     

Potential effets of ginkgo (Ginkgo biloba,L.) on female reproduction

This minireview will briefly outline the basic knowledge concerning the provenance, biological active constituents of ginkgo (Ginkgo biloba, L.) and its general health effects. Ginkgo has been shown to affect female reproductive functions: it can affect ovarian folliculo- and oogenesis, embryogenesis, promote ovarian granulosa cell apoptosis, reduce their proliferation and the release of ovarian hormones. Usually, ginkgo extract mainly suppresses, but its constituents like amifostine, leuprorelin, quercetin and kaempherol can promote ovarian functions. This may indicate the existence of anti-reproductive ginkgo constituent(s), such as ginkgolide B and allopregnenolone which, like ginkgo extract, can promote ovarian cell apoptosis and suppress ovarian follicullogenesis and oogenesis. Ginkgo effects could be mediated by an action on brain functions, ovarian steroidogenesis, oxidative processes, intracellular regulators of ovarian cell proliferation and apoptosis and GABA receptors. Ginkgo and its molecules, ginkgolide B and allopregnenolone can be useful for prevention and treatment of reproduction-related disorders like ovarian cancer, ovarian ischemia and menopausal syndrome. On the other hand, its constituents amifostine, leuprorelin, quercetin and kaempherol could be potentially applicable as biostimulators of female reproductive processes in human and veterinary medicine and animal production. Nevertheless, application of ginkgo is still limited by insufficient or contradictory knowledge concerning its active constituents, characters, targets and mediators of its action and their functional interrelationships. Impact of ginkgo action on reproductive organs other than ovaries remains largely unknown. Addressing these issues with proper animal and clinical studies could help to understand the distinct efficacy and consequences of medical application of ginkgo.     

银杏叶中叶绿素衍生物的反相高效液相色谱分析

以检测植物色素降解过程中叶绿素衍生物的变化为主要目的,采用反相高效液相色谱,结合光电二极管阵列和荧光检测技术,分析了银杏叶中叶绿素衍生物的组成和含量变化,发现在衰老的银杏叶中主要存在叶绿素a、叶绿素b和脱镁叶绿素a,而其他降解产物并未大量累积。     

Antimicrobial activity and phytochemical screening of Ocimum americanum L extracts against pathogenic microorganisms

The aim of the present study is to assess the antimicrobial activities of various leaf extracts of Ocimum americanum were tested against pathogenic microorganisms. Preparation of different extracts viz., aqueous, acetone, ethyl acetate and methanol through soxhlet extraction method. Various extracts were investigated against MTCC strains of Bacillus cereus, Clostridium penfrigens, Klebsilla pnemoniae, Salmonella paratyphi, Candida albicans and Aspergillus niger by agar well diffusion and disc diffusion methods. Minimum inhibitory concentration (MIC), Minimum Bactericidal/Fungicindal Concentration (MBC/MFC) were determined through micro dilution method. Elucidation of phytochemicals and functional groups were observed by HPLC and FT-IR respectively. Ethyl acetate leaf extract of O.americanum showed significant antimicrobial activity against the all tested pathogens in agar well diffusion method in which B.cereus (17 mm) was observed high zone of inhibition. Whereas lowest inhibition was observed in aqueous extract against C.pentrigens (7 mm). The ranges of MIC values from 0.78 μg/ml to 50 μg/ml and MBC/MFC 1.56 μg/ml to 50 μg/ml were observed. Phytochemicals such as alkaloids, steroids, saponins, flavonoids, tannins, terepenes, phenolic compounds cardiac glycosides were detected. Saponinns, flavonoids, tannins, phenolic compounds were observed in only ethyl acetate leaf extracts. Functional group of the leaf extracts was exhibited by FTIR and HPLC analysis of the ethyl acetate leaf extract was elutated at six peaks. Based on the results we concluded that ethyl acetate leaf extract of O.americanum has proved to be potentially effective than the other extracts. Therefore, ethyl acetate leaf extract of O.americanum could act as antimicrobial agent and further studies are recommended for isolation of compounds and toxicological studies.     

银杏叶中聚戊烯醇含量及其季节性变化

银杏 (ＧｉｎｋｇｏｂｉｌｏｂａＬ .)叶中聚戊烯醇 (ｐｏｌｙｐｒｅｎｏｌｓ)含量较高[1] ,聚戊烯醇在人体中是多萜醇的中间体[2 ] ,对细胞膜糖蛋白生物合成具有重要作用[3 ] ,用于多发性硬化症 (痛风 ,红斑狼疮等 )等免疫功能疾病、糖尿病、慢性肝炎及肿瘤病人化疗的辅助治疗     

Cellulose structure and lignin distribution in normal and compression wood of the Maidenhair tree(Ginkgo biloba L.)

We studied in detail the mean micro fibril angle and the width of cellulose crystals from the pith to the bark of a 15-year-old Maidenhair tree(Ginkgo biloba L.). The orientation of cellulose micro fibrils with respect to the cell axis and the width and length of cellulose crystallites were determined using Xray diffraction. Raman microscopy was used to compare the lignin distribution in the cell wall of normal/opposite and compression wood, which was found near the pith. Ginkgo biloba showed a relatively large mean micro fibril angle,varying between 19° and 39° in the S2 layer, and the average width of cellulose crystallites was 3.1–3.2 nm. Mild compression wood without any intercellular spaces or helical cavities was observed near the pith. Slit-like bordered pit openings and a heavily lignified S2 L layer con firmed the presence of compression wood. Ginkgo biloba showed typical features present in the juvenile wood of conifers. The micro fibril angle remained large over the 14 annual rings. The entire stem disc,with a diameter of 18 cm, was considered to consist of juvenile wood. The properties of juvenile and compression wood as well as the cellulose orientation and crystalline width indicate that the wood formation of G. biloba is similar to that of modern conifers.     

银杏叶黄酮提取方法比较

比较不同溶剂提取银杏（ＧｉｎｋｇｏｂｉｌｏｂａＬ．）叶黄酮类化合物的提取效率,从成本效益角度考虑,以７０％乙醇作为提取溶剂更为有利。在分级沉淀中,黄酮含量与蛋白质含量呈正相关,在乙醇提取液中黄酮和蛋白质含量最高;蛋白质的存在有助于提高黄酮的溶解度。乙醇提取液用饱和（ＮＨ４）２ＳＯ４浓缩两次,可使醇相中的黄酮沉淀析出。根据试验结果,提出了银杏叶黄酮的优化提取方法。