Furfural Derivatives and Phenolic Constituents in Stemona tuberosa Lour

Chemical investigation on the water-soluble constituents of Stemona tuberosa Lour. resulted in the isolation of a previously undescribed furfural derivative namely (S)-5-((R)-hydroxy(5-(hydroxymethyl)furan-2-yl)methyl)-5-methylfuran-2(5H)-one and twenty-five known compounds from the water decoction of the dried root tubers. Their structures were determined by analysis of the extensive spectroscopic data, including 1D/2D NMR, HR-ESI-MS, and ORD, as well as the ECD simulation and comparison. Most of them were phenolic and among them, four compounds were isolated from Stemona plants for the first time. This study uncovers diverse constituents from water decoction of S. tuberosa dedicated for its quality control and allows for the exploitation of chemical markers with potential significance for discrimination of Stemona plants.     

Antioxidant dehydrotocopherols as a new chemical character of Stemona species

From the roots of various Stemona species four new dehydrotocopherols (chromenols) were isolated and their structures and stereochemistry elucidated by spectroscopic methods. The double bond between C-3 and C-4 proved to be a typical chemical character of the genus found in most of the species. Various C-methylations of the aromatic ring reflect differences in methyltransferase activities and agreed with the current species delimitations showing an exclusive accumulation of dehydro-delta-tocopherol for the Stemona tuberosa group, whereas different provenances of Stemona curtisii were characterized by dehydro-gamma-tocopherol accompanied by small amounts of dehydro-alpha-tocopherol. From Stemona collinsae all four tocopherols were isolated with a clear preponderance of dehydro-delta-tocopherol accompanied by smaller amounts of the rare dehydro-beta-tocopherol. Stemona burkillii and a group of unidentified species showed a weak accumulation trend towards dehydro-alpha-tocopherol, whereas Stemona cochinchinensis and especially Stemona kerrii clearly differed by a preponderance of chromanol derivatives. In Stemona cf. pierrei no tocopherols could be detected at all. Based on TLC tests and microplate assays with the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH*) the antioxidant capacities of all chromenol derivatives were comparable with that of alpha-tocopherol showing no significant differences among each other, except for a more rapid kinetic behaviour of the 5,7,8-methylated dehydro-alpha-tocopherol.     

Isolation and chemotaxonomic significance of tuberostemospironine-type alkaloids from Stemona tuberosa

An alkaloid named 6alpha-hydroxycroomine (1) as well as the known croomine (2), both belonging to the tuberostemospironine-alkaloid type, were isolated from Stemona tuberosa as the major components. The structure of 1 was elucidated through extensive spectroscopic analyses. Comparison of the HPLC profiles of the total alkaloids and the crude methanol extract showed that both compounds are naturally occurring. The first isolation of 1 and 2 from S. tuberosa has chemotaxonomic significance, confirming the close relationship between Stemona and Croomia. The trnL sequences of plants from the four genera of Stemonaceae cluster together as a clade, further lending support to retaining them in a single family.     

Antibacterial stilbenoids from the roots of Stemona tuberosa

Twelve dihydrostilbenes, stilbostemins N-Y (1-12), and a phenanthraquinone, stemanthraquinone (13), were isolated and identified from roots of Stemona tuberosa, along with five known dihydrostilbenes. Their structures were established on the basis of 1D and 2D NMR and other spectroscopic analyses. Dihydrostilbene 8 exhibited strong activity against Bacillus pumilus (MIT 12.5-25 microg/mL). Many tested compounds exhibited moderate antibacterial activities.     

Isolation of chlorogenic acids and their derivatives from Stemona japonica by preparative HPLC and evaluation of their anti-AIV (H5N1) activity in vitro

Two chlorogenic acids and five chlorogenic acid derivatives were simultaneously separated and purified from Stemona japonica by preparative high-performance liquid chromatography. Five of the collected compounds were over 95% pure while the other two compounds were over 90% pure. Their structures were elucidated as 3-O-feruloylquinic acid (1), 4-O-feruloylquinic acid (2), methyl 3-O-feruloylquinate (3), methyl 5-O-caffeyolquinate (4), methyl 4-O-feruloylquinate (5), ethyl 3-O-feruloylquinate (6) and the new compound ethyl 4-O-feruloylquinate (7) by UV, NMR and ESI-MS. All compounds were obtained from Stemona species for the first time, however compounds 6 and 7 are believed to be artefacts from the ethanol extraction. The anti-AIV (H5N1) activities were evaluated by Neutral Red uptake assay. Compounds 3 and 4 exerted moderate inhibitory effect against AIV (H5N1) in vitro.     

Insecticidal pyrido[1,2-a]azepine alkaloids and related derivatives from Stemona species

Eight new alkaloids, the pyrido[1,2-a]azepines stemokerrin, methoxystemokerrin-N-oxide, oxystemokerrin, oxystemokerrin-N-oxide, and pyridostemin, along with the pyrrolo[1,2-a]azepines dehydroprotostemonine, oxyprotostemonine, and stemocochinin were isolated from four Stemona species together with the known compounds protostemonine, stemofoline, 2'-hydroxystemofoline, and parvistemonine. Their structures were elucidated by 1H and 13C NMR including 2D methods and two key compounds additionally by X-ray diffraction. Besides the formation of a six membered piperidine ring, additional oxygen bridges and N-oxides contributed to structural diversity. The co-occurrence of pyrrolo- and pyridoazepines suggested biosynthetic connections starting from more widespread protostemonine type precursors. Bioassays with lipophilic crude extracts against Spodoptera littoralis displayed very strong insecticidal activity for the roots of S. curtisii and S. cochinchinensis, moderate activity for S. kerrii, but only weak effects for the unidentified species HG 915. The insect toxicity was mainly caused by the accumulation of stemofoline, oxystemokerrin, and dehydroprotostemonine displaying two different modes of action. Based on the various insecticidal activities of 13 derivatives structure-activity relationships became apparent.     

Dihydrophenanthrenes and other antifungal stilbenoids from Stemona cf. pierrei

Three new dihydrophenanthrenes, stemanthrenes A-C, along with the new dihydrostilbene stilbostemin G were isolated and identified from the underground parts of Stemona cf. pierrei together with the known pinosylvin, 4'-methylpinosylvin, dihydropinosylvin, stilbostemins B, D, and E as well as the pyrrolo[1,2-a]azepine alkaloids protostemonine and stemonine. The structures of all new stilbenoids, elucidated by NMR analyses, showed a common substitution pattern for aromatic ring A and characteristic C-methylations for ring B. The trivial name racemosol, previously reported for S. collinsae, was renamed to stemanthrene D due to its priority for another compound. Bioautographic tests on TLC plates with Cladosporium herbarum displayed high antifungal activity for compounds with an unsubstituted aromatic ring A, e.g. pinosylvin, but only weak effects for the higher substituted stilbostemin G and stemanthrenes A-C. Similar results were obtained by germ tube inhibition of five microfungi using 2-fold serial broth dilutions determined by a microplate reader. Because of weak inhibition and chemical instability of stemanthrenes, no EC(50) and EC(90) values could be calculated.     

白毛茛中生物碱的提取和HPLC分析

白毛茛根粉末经室温萃取后用HPLC分析其中的生物碱成分,色谱柱为Zorbax Eclipse XDBC18快速分离,该方法可准确测定白毛茛中主要的生物碱,包括小檗碱（berberine）和白毛莨碱（hydrastine）。萃取和HPLC分析还可用于其他几种生物碱的测定,包括氢化小蘖碱（canadine）、白毛莨分碱（hydrastinine）和巴马亭（palmatine）,也可以应用于其它含小檗碱的植物根。Eclipse XDBC18快速分离柱采用等梯度分离,所有组分在15min内获得了高的分离度。     

植物根构型的定量分析

植物根系具有锚定植株、吸收和运输土壤中的水分及养分、合成和贮藏营养物质等重要功能。根构型是根系在土壤中的空间造型和分布。对植物根构型进行定量分析,有助于人们了解根系结构和根系功能在生态系统中的重要作用。本文对植物根构型的概念及其定量分析研究进展进行了概述,并介绍了植物根构型的主要研究方法和定量分析技术。     

HPLC法测定花生根中白藜芦醇的含量

本文采用反相高效液相色谱法测定了花生根中白藜芦醇的含量.选用ODS-C18色谱柱(200 mm×4.6mm,5μm),以甲醇-水(4555)为流动相,流速为0.5 mL/min,紫外检测波长为303nm.结果表明,白藜芦醇峰面积与其浓度之间呈现良好的线性关系,线性回归方程为Y=15879.28X+12350.2,相关系数为0.9996.方法简单,快速,精密度好,回收率为98.8%,相对标准偏差为1.79%.     

金沙江河谷特有药用植物——云南百部的分类学处理

通过对云南百部（Stemona mairei（H.Lév.）K.Krause）及其形态相似种金沙江百部（S.jinshajiangensis X. D. Cong et G. J. Xu）和变种滇北百部（S.jinshajiangensis var.dianbeiensis X. D. Cong et G. J. Xu）模式标本采集地野外居群植株的实地调查和研究,发现金沙江百部及其变种滇北百部的形态特征变异式样均在云南百部形态特征的正常变异范围内,因此将金沙江百部及其变种处理为云南百部的异名,同时对云南百部的形态特征进行了补充描述。结合对云南百部6个野生居群成熟植株的开花结实特征、种子传播策略分析,对云南百部受威胁状况进行了评估。     

四种五加果实的活性成分的HPLC定量比较分析

首次系统地对短梗五加、糙叶五加、藤五加、窄叶藤五加四种五加属植物果实中的金丝桃苷、芦丁、槲皮素、山奈素、6,7-二甲氧基香豆素、紫丁香苷等6种活性成分进行了含量比较。采用RP-HPLC测定各个活性成分的含量。色谱柱为ODS C18柱,各活性成分的含量测定均选择最优的色谱条件和供试品溶液制备方法。结果显示:糙叶五加,藤五加,窄叶藤五加果实中除紫丁香苷外的其他活性成分含量均高于短梗五加,但尚未得到有效利用,具有相当好的开发前景。     

Pyrrolo- and pyridoazepine alkaloids as chemical markers in Stemona species

Broad-based phytochemical investigations on 31 Stemona species and geographical provenances led to an overview concerning characteristic accumulation trends and the distribution of different Stemona alkaloids. Two major metabolic differences suggested a taxonomic segregation of the complex Stemona tuberosa group from the other species, and was supported by morphological characters. Whereas most of the Stemona species were characterised by protostemonine type alkaloids, the S. tuberosa group clearly deviated by accumulation trends towards tuberostemonine or croomine derived alkaloids belonging to two different skeletal types. Also of chemotaxonomic relevance was the structural divergence of protostemonine type alkaloids into pyrrolo- or pyridoazepine derivatives represented by stemofoline or oxystemokerrine, respectively, as major constituents. Their common occurrence in different provenances of S. curtisii, also deviating from the other species by various chromosome numbers, deserves special taxonomic attention. Species specific chemical markers were given by the unique accumulation of didehydrostemofoline (=asparagamine A) in S. collinsae and stemokerrine in S. kerrii. In contrast to previous reports, no bisdehydro derivatives with an aromatic pyrrole ring were detected supporting the hypothesis that these alkaloids are artifacts. A new stereoisomer of tuberostemonine was isolated and identified by spectroscopic methods.     

百部总生物碱含量测定方法的研究

分别运用酸碱滴定法和雷氏盐吸收系数法对百部中总生物碱的含量进行了测定,并加以比较。结果表明：雷氏盐吸收系数法的测定结果比酸碱滴定法的测定结果稍高,提取步骤少,操作简单,更能最大限度的减少干扰因素的影响,方法学考察均符合规定,可以用来测定百部总碱的含量．     

坚龙胆环烯醚萜甙的HPLC分析

应用HPLC分析方法,建立了坚龙胆中5个主要环烯醚萜甙的含量测定方法。在ZORBAXSB—C18色谱柱,乙腈-0．2％磷酸水溶液为流动相,梯度洗脱,流速1．0mL/min,柱温为40℃,检测波长254nm的色谱条件下,化合物得到良好的分离,并具线性相关。本方法操作简便,重现性好,灵敏度高。对不同产地的样品进行比较分析的结果表明,产地对坚龙胆中环烯醚萜甙的组成和含量有显著的影响。     

Novel alkaloids from the roots of Stemona sessilifolia

Four new Stemona alkaloids, sessilistemonamines A-C (1-3, resp.) and dihydrostemoninine (4), were isolated from the roots of Stemona sessilifolia. Their structures and relative configurations were elucidated by means of in-depth 1D- and 2D-NMR-spectroscopic as well as mass-spectrometric experiments; and the structure of 4 was solved by X-ray single-crystal diffraction. The stereoisomeric compounds 1-3 share an unprecedented tetracyclic decahydro-1H-furo[2',3':4,5]cyclopenta[1,2-b]pyrrolo[1,2-a]azepine nucleus. Compounds 1 and 2 were found to be moderately active in terms of acetylcholinesterase (AchE) inhibition, with IC50 values of 68.8+/-9.5 and 17.1+/-2.5 microM, resp.     

HPLC Analysis of Neurophysin Proteins from Neurosecretory Granules

Abstract: Neurosecretory granules were obtained from neurolobes of porcine pituitary glands. From the granules, highly purified neurophysins were prepared by HPLC. According to polyacrylamide gel electrophoresis, isoelectric focusing, N- and C-terminal amino acid residue determination, and amino acid composition, the neurophysins I₁ I₂, and II were identical to the neurophysins obtained from whole posterior lobes. Since degradation could not have occurred, we conclude that neurophysin I₁ and I₂ originated in the neurosecretory granules.     

HPLC法测定抗宫炎凝胶剂中金石蚕苷含量的研究

目的:采用高效液相色谱法(HPLC)测定抗宫炎凝胶剂中金石蚕苷的含量,为制定其质量标准提供基础。方法:采用十八烷基硅烷键合胶为填充剂,乙腈-0.5%磷酸(18:82)为流动相;检测波长为332 nm;流速为1.0 ml/min,探讨HPLC测定抗宫炎凝胶剂中金石蚕苷含量的专属性、精密度、稳定性、重现性等。结果:金石蚕苷在0.104~0.468 mg/ml范围内呈良好的线性关系(r=0.9999),平均回收率为99.76%,RSD为1.56%。结论:采用HPLC测定抗宫炎凝胶剂中金石蚕苷含量的专属性、精密度、稳定性、重现性均良好,该方法简便可靠,可用于抗宫炎凝胶剂的质量标准的研究。     

单棕榈酰莽草酸的高效液相色谱-蒸发光散射检测法定量测定

本文建立一种采用高效液相色谱-蒸发光散射检测法定量测定单棕榈酰莽草酸的方法。色谱条件:色谱柱:反相Symmetry C18柱4.6×250 mm i.d.(填料粒度5μm),柱温30℃,流动相:乙腈-水-甲酸(80∶20∶0.2);流速0.8 mL/min;ELSD漂移管温度:80℃,载气流速:2 L/min。3-,4-和5-棕榈酰莽草酸纯品采用酶法合成,合成产物经柱层析和高效液相色谱制备纯化得到纯品。在该色谱条件下,3-,4-和5-棕榈酰莽草酸在0.21~4.12μg的范围内,其质量与其峰面积线性关系良好(r=0.9991,0.9998,0.9997),回收率分别为95.2~98.7%,96.1%~98.2%,96.3%~98.5%;RSD分别为1.6%,1.8%,1.9%。实验结果表明该方法具有简便、快速、准确、重现性较好的特点,可以用于定量分析单棕榈酰莽草酸,尤其适用于非水相酶促反应合成体系中的产物检测。     

植物根构型的定量分析

植物根系具有锚定植株、吸收和运输土壤中的水分及养分、合成和贮藏营养物质等重要功能。根构型是根系在土壤中的空间造型和分布。对植物根构型进行定量分析, 有助于人们了解根系结构和根系功能在生态系统中的重要作用。本文对植物根构型的概念及其定量分析研究进展进行了概述, 并介绍了植物根构型的主要研究方法和定量分析技术。