Characterization of flavonoids in the traditional Chinese herbal medicine-Huangqin by liquid chromatography coupled with electrospray ionization mass spectrometry

The root of Scutellaria baicalensis, called Huangqin in Chinese, is one of the most commonly used traditional Chinese medicines for the treatment of hepatitis, tumors, diarrhea, and inflammatory diseases. The major chemical constituents of Huangqin are flavonoids. In the present paper, HPLC-DAD-ESI-MS(n) was used to analyze flavonoids in the roots of S. baicalensis. A total of 26 flavonoids were identified or tentatively characterized, including 5 C-glycosides, 12 O-glycosides, and 9 free aglycones. Two C-glycosides, apigenin-6-C-glucyl-8-C-arabinoside and chrysin-6,8-di-C-glucoside, together with some O-glycosides, are reported from S. baicalensis for the first time. This method is simple, reliable and sensitive, and could be used for the quality control of Huangqin and its related preparations.     

松嫩平原针茅草原的特征及其生态地理规律的探讨

 经考察,松嫩平原的针茅草原主要有4个群落类型：贝加尔针茅(Stipa baicalensis)群落、贝加尔针茅+线叶菊(Filifolium sibiricum)群落、大针茅(S．grandis)+贝加尔针茅群落和大针茅群落。通过对针茅草原各类型基本结构特征和生态地理分布规律的分析,并根据它们所反映的水土条件的差异,认为贝加尔针茅群落为该地区的地带性植被。在中国温带草原区划中的位置属于草甸草原,应与内蒙古高原典型草原分开,成为一个独立的分区     

不同花色黄芩中dfr基因的克隆及时空表达分析

二氢黄酮醇-4-还原酶(Dihydroflavonol-4-reductase,Dfr)是类黄酮生物合成途径中调控花青素和原花青素合成的关键酶。为探究dfr基因在同一生态环境下不同花色黄芩中的差异,以白色、紫红色和紫色3种花色的黄芩花瓣cDNA为模板,基于同源克隆和RACE技术从中克隆得到3个完整的dfr基因全长序列,分别命名为Sbdfr1、Sbdfr2、Sbdfr3,并采用生物信息学软件对其相关结构进行分析。结果表明,3个Dfr蛋白均存在高度保守的NADPH结合位点和底物特异性结合位点。系统进化分析表明,三者与已知粘毛黄芩(GenBank登录号:ACV49882.1)聚为一簇,亲缘关系最近;关键结构域和3D模型分析发现3个Dfr蛋白表面催化活性区域均存在差异,其独特的结构特性为研究Dfr底物特异性提供了有利条件。qRT-PCR分析显示,dfr在3种花色黄芩盛花期除根外的其他组织中均有不同程度的表达;在花瓣发育进程中,dfr基因在白花和紫花黄芩中的表达量均呈上升趋势,在紫红花黄芩中的表达量先缓慢上升后下降,之后再迅速上升至最大值。研究结果为进一步深入探究Dfr底物选择性的机理及功能提供一定的理论基础,对阐明黄芩花色差异变化的分子机理具有重要的科学研究价值。     

内蒙古高原针茅摹群落β多样性研究

用比较样地法调查了内蒙古高原４类地带性针茅（Ｓｔｉｐａ）草原群落的β多样性特征。结果表明,Ｗｈｉｔｔａｃｋｅｒ指数βＷＳ与尺度有关,随取样面积的增加,βＷＳ逐渐降低,取样面积相同时,４类群落的βＷＳ比较接近,各群落 的Ｃｏｄｙ指数最初也随样方面积的扩大而增大,当样方面积扩大到一定尺度时,贝加尔针茅群落和大针茅群落为〉０．５ｍ＾２,克氏针茅群落和小针茅群落为〉２ｍ＾２,Ｃｏｄｙ指数趋于稳定。同一尺度     

Identification and determination of major flavonoids in rat serum by HPLC-UV and HPLC-MS methods following oral administration of Dalbergiaodorifera extract

The major flavonoids in rat serum after oral administration of Dalbergia odorifera extract were analyzed qualitatively and quantitatively by high performance liquid chromatography (HPLC) and its coupling to mass spectrometry (HPLC-MS). Utilizing HPLC-MS technique, 18 flavonoids including five isoflavones, four isoflavanones, four neoflavones, two flavanones, two chalcones, one isoflavanonol were identified in free form in serum sample based on comparison with the authentic standards. Furthermore, the amounts of the four prominent flavonoids, (3R)-4'-methoxy-2',3,7-trihydroxyisoflavanone, vestitone, formononetin and sativanone were determined in serum by HPLC-UV with internal standard method. The method was validated and utilized in pharmacokinetic studies of these four analytes. This is the first report on identification and determination of the major flavonoids in rat serum after oral administration of D. odorifera extract and the results provided a firm basis for clarifying the pharmacological effect of D. odorifera and evaluating the clinical applications of this medicinal herb.     

葡萄果粒表皮酵母菌多样性研究

从新疆、甘肃、陕西、宁夏、山东主要酿酒葡萄产区收集葡萄果粒并分离得到酵母258株, 利用26S rDNA的D1/D2区序列分析并结合形态学、生理学特征对这些菌株进行了分类学研究, 探讨了这些地区葡萄果粒表皮酵母的物种多样性及其分布。共鉴定出13属26种, 其中优势属为汉逊酵母属Hanseniaspora(5种), 假丝酵母属Candida(4种), 毕赤酵母属Pichia(4种)和伊萨酵母属Issatchenkia(2种)。对分离自不同地域的同种内不同菌株进行了D1/D2序列分析比较, 以探讨不同地理起源地酵母种内序列稳定性及其变异。     

葡萄果粒表皮酵母菌多样性研究

从新疆、甘肃、陕西、宁夏、山东主要酿酒葡萄产区收集葡萄果粒并分离得到酵母258株,利用26S rDNA的D1/D2区序列分析并结合形态学、生理学特征对这些菌株进行了分类学研究,探讨了这些地区葡萄果粒表皮酵母的物种多样性及其分布.共鉴定出13属26种,其中优势属为汉逊酵母属Hanseniaspora(5种),假丝酵母属Candida(4种),毕赤酵母属Pichia(4种)和伊萨酵母属Issatchenkia(2种).对分离自不同地域的同种内不同菌株进行了D1/D2序列分析比较,以探讨不同地理起源地酵母种内序列稳定性及其变异.     

Anticancer diarylheptanoid glycosides from the inner bark of Betula papyrifera

Phytochemical investigations of the MeOH extract of Betula papyrifera inner bark led to the isolation of ten phenolic compounds of the following types: diarylheptanoid glycosides (1-4), a diarylheptanoid (5), a lignan (6), flavonoids (7-8) and chavicol glycosides (9-10). Among them, the diarylheptanoid glycoside, (S)-1,7-bis-(4-hydroxyphenyl)-heptan-3-one-5-O-alpha-L-arabinofuranosyl-(1-->6)-beta-D-glucopyranoside, papyriferoside A (1), was isolated and its structure was determined on the basis of 1D and 2D NMR, HPLC-MS, as well as high resolution mass spectroscopic data. Platyphylloside (4) exerted the strongest cytotoxic activity of all isolated compounds with IC(50) values ranging from 10.3 to 13.8 microM.     

Constituents of Afzelia bella stem bark

The stembark of Afzelia bella yielded an acylated dihydroflavonol glycoside identified as 2R,3R-trans-aromadendrin-7-O-beta-D-glucopyranoside-6'-(4'-hydroxy-2'-methylene butanoate), along with five known flavonoids and the lignan glycoside (+)-isolariciresinol 9-O-xyloside. Their structures were determined by detailed 1D and 2D NMR analyses.     

Polysaccharides of diatoms occurring in Lake Baikal

Polysaccharide composition of neutral, acid- and alkali-soluble fractions of the diatoms Stephanodiscus meyerii Genkal et Popovsk and Aulacoseira baicalensis (K. Meyer) Simonsen of Lake Baikal has been studied. Neutral polysaccharides were represented by chrysolaminarans (1-->3;1-->6-beta-D-glucans). The chrysolaminaran from S. meyerii consists of the high- and low-molecular-weight fractions (40 and 2-5 kDa, respectively) and contains a large number of beta-1-->6-bound glucose residues. The chrysolaminaran from A. baicalensis is a low-molecular-weight 1-->3:1-->6-beta-D-glucan containing a small number of beta-1-->6 bonds, with mannitol being attached to the reducing unit of its chain. Acid- and alkali-soluble polysaccharide fractions are practically absent in S. meyerii. The alkali-soluble fraction from A. baicalensis is a low-molecular-weight (2-kDa) glycoprotein, the carbohydrate moiety of which is represented by a heteropolysaccharide.     

Analysis of Grassland Vegetation of the Southwest Heilongjiang Steppe (China) Using the Power Law

In 1997, we conducted a vegetation survey in three semi-arid natural grasslands (steppes) withdifferent livestock grazing intensities in Southwest Heilongjiang Province, China. The dominant grasslandspecies was the grass Stipa baicalensis Roshev. Grasslands with light, intermediate, and heavy grazingintensities were located 10, 5, and 2 km from a village, respectively. Villagers use the steppe to raise cattle,horses, sheep, and goats. Each of the three grasslands was surveyed by placing 100 quadrats (50 cm×50 cm)along a 50 m line transect. Each quadrat was divided into four equal areas (25 cm×25 cm; S-quadrats) and allplant species occurring in each of these smaller areas were identified and recorded. These data were summa-rized into frequency distributions and the percentage of S-quadrats containing a given species and thevariance of each species were estimated. The power law was applied to these estimates. The power law wasused to evaluate the spatial heterogeneity and frequency of occurrence for each species in the grasslandcommunity. The lightly grazed grassland exhibited high spatial heterogeneity (caused by large plant size),the highest species diversity, and a high occurrence of S. baicalensis. In contrast, the heavily grazedgrassland exhibited high spatial heterogeneity (caused by patchy populations of small plant size), lowspecies diversity, and a low occurrence of S. baicalensis. We judged that the heavily grazed grassland wasovergrazed and exclusion of livestock from the degraded areas is necessary for recovery.     

黄芩种质资源ISSR遗传多样性的分析及评价

采用ISSR分子标记技术对6个野生或栽培居群共147份黄芩种质进行遗传多样性分析和评价。分析结果表明,51个ISSR引物中筛选出18条扩增条带清晰、重复性好和多态性高的引物,共扩增出485条清晰的条带,其中466条具有多态性,平均多态性位点比率为96.08%,平均Nei’s基因多样性指数和Shannon’s信息指数分别为0.244 4和0.388 9,等位基因数（Na）和有效等位基因数（Ne）分别为1.993 8和1.383 9,遗传分化指数G_st=0.122 3,遗传一致度（I）和遗传距离（D）分别为0.951 5和0.050 1,说明收集的黄芩种质资源在总体上具有较高的遗传多样性,不同居群间存在一定的遗传分化和基因交流,遗传变异主要存在于居群内。分子聚类结果表明,同一地区的种质并没有按照收集来源完全聚类,可能与种质不同起源或民间栽培引种有关。在DNA分子水平揭示黄芩种质资源的遗传多样性水平,将为进一步黄芩种质资源评价、保存和新品种选育等利用提供依据。     

Analysis of Grassland Vegetation of the Southwest Heilongjiang Steppe （China） Using the Power Law

In 1997, we conducted a vegetation survey in three semi-arid natural grasslands （steppes） with different livestock grazing intensities in Southwest Heilongjiang Province, China, The dominant grassland species was the grass Stipa baicalensis Roshev. Grasslands with light, intermediate, and heavy grazing intensities were located 10, 5, and 2 km from a village, respectively. Villagers use the steppe to raise cattle, horses, sheep, and goats. Each of the three grasslands was surveyed by placing 100 quadrats （50 cm×50 cm） along a 50 m line transect. Each quadrat was divided into four equal areas （25 cm×25 cm; S-quadrats） and all plant species occurring in each of these smaller areas were identified and recorded. These data were summarized into frequency distributions and the percentage of S-quadrats containing a given species and the variance of each species were estimated. The power law was applied to these estimates. The power law was used to evaluate the spatial heterogeneity and frequency of occurrence for each species in the grassland community. The lightly grazed grassland exhibited high spatial heterogeneity （caused by large plant size）, the highest species diversity, and a high occurrence of S. baicalensis. In contrast, the heavily grazed grassland exhibited high spatial heterogeneity （caused by patchy populations of small plant size）, low species diversity, and a low occurrence of S. baicalensis. We judged that the heavily grazed grassland was overgrazed and exclusion of livestock from the degraded areas is necessary for recovery.     

Chemosystematic value of flavonoids from Crataegus x macrocarpa (Rosaceae) with special emphasis on (R)- and (S)-eriodictyol-7-O-glucuronide and luteolin-7-O-glucuronide

The chemotaxonomic investigation of Crataegus x macrocarpa, a hybrid of C. laevigata and C. rhipidophylla, presents the qualitative and quantitative composition of its flavonoid pattern in relationship to its parent species for the first time. Six flavonoids were identified as vitexin-2'-O-rhamnoside (1), vitexin (2), isovitexin (3), rutin (4), hyperoside (5), and isoquercitrin (6). Furthermore, two flavonoids were isolated from C. x macrocarpa and identified as a diastereoisomeric mixture of (R)- and (S)-eriodictyol-7-O-beta-D-glucuronide (7) and luteolin-7-O-beta-D-glucuronide (8) by means of 1D- and 2D-NMR, MS, and UV experiments. Compounds 7 and 8 were isolated for the first time from Crataegus species. While missing in C. laevigata, their occurrence in C. rhipidophylla additionally emphasizes its chemotaxonomic relationship to C. x macrocarpa.     

Free radical scavenging and antioxidant activities of flavonoids extracted from the radix of Scutellaria baicalensis Georgi

Free radical scavenging and antioxidant activities of baicalein, baicalin, wogonin and wogonoside, the four major flavonoids in the radix of Scutellaria baicalensis Georgi, were examined in different systems. ESR results showed that baicalein and baicalin scavenged hydroxyl radical, DPPH radical and alkyl radical in a dose-dependent manner, while wogonin and wogonoside showed subtle or no effect on these radicals. Ten micromol/l of baicalein and baicalin effectively inhibited lipid peroxidation of rat brain cortex mitochondria induced by Fe(2+)-ascorbic acid, AAPH or NADPH, while wogonin and wogonoside showed significant effects only on NADPH-induced lipid peroxidation. In a study on cultured human neuroblastoma SH-SY5Y cells system, it was found that 10 micromol/l of baicalein and baicalin significantly protected cells against H(2)O(2)-induced injury. Baicalein was the most effective antioxidant among the four tested compounds in every system due to its o-tri-hydroxyl structure in the A ring. Compared with a well-known flavonoid, quercetin, the antioxidant activity of baicalein was lower in DPPH or AAPH system, but a little higher in those systems which might associate with iron ion. These results suggest that flavonoids in the radix of Scutellaria baicalensis with o-di-hydroxyl group in A the ring, such as baicalein and baicalin, could be good free radical scavengers and might be used to cure head injury associated with free radical assault.     

Antibacterial activity of flavonoids against methicillin-resistant Staphylococcus aureus strains

An experimental and theoretical study was performed on the anti-staphylococcal activity of 18 natural and synthetic flavonoids against methicillin-resistant Staphylococcus aureus strains. The analysed flavonoids belong to three well-differentiated structural patterns: chalcones, flavanones and flavones. The quantitative analysis of the anti-staphylococcal activity of the compounds was carried out by determining their percent inhibition degree. The hierarchical cluster analysis method was used to analyse the anti-MRSA activity of the compounds. With this methodology, the flavonoids were classified into four groups according to their anti-staphylococcal activity (high, sufficient, intermediate and low). The carbonylic region is of importance because it is part of the bioactive region inducing anti-MRSA activity in the flavonoid molecules. The introduction of OH groups in positions 2' of chalcones and 5 of flavanones (or flavones) increases flavonoid activity, while the OCH(3)groups produce the reverse effect. Using the experimental anti-MRSA activity data of flavonoids and six quantum chemical parameters calculated by means of the AM1 semiempirical molecular orbital method, a very good quantitative structure-activity relationship was obtained (confidence range: 95%; significance level for tests: 0.05; correlation coefficient=0.9842). The selected parameters explain 96.86% of the percent inhibition degree. The obtained relation is consistent with the conclusions formulated in this paper and serves as a theoretical support for some of them. Finally, it is concluded that the flavonoids chalcone, 2'(OH)-chalcone, 2',4'(OH)(2)-chalcone and 2',4(OH)(2)-chalcone might constitute promising therapeutic agents against infections with methicillin-resistant S. aureus strains.     

Tyrolobibenzyls E and F from Scorzonera humilis and distribution of caffeic acid derivatives,lignans and tyrolobibenzyls in European taxa of the subtribe Scorzonerinae (Lactuceae,Asteraceae)

A chemosystematic study of the subtribe Scorzonerinae, a subtribe of the Lactuceae tribe of the Asteraceae family was performed, using the recently discovered tyrolobibenzyls as well as lignans and caffeic acid derivatives as diagnostic characters. In addition to the known compounds two new tyrolobibenzyls (E and F) were isolated and their structures were established by mass spectrometry and 1D and 2D NMR spectroscopy. Twenty four samples from rootstocks of seventeen different Scorzonerinae taxa, comprising members of three genera (Podospermum, Scorzonera, and Tragopogon), were analyzed. Tyrolobibenzyls A (1), B (2), C (5), D (3), E (6), and F (4) were identified in crude extracts by means of HPLC retention times, on-line UV spectra and on-line MS/MS spectra. Quantification of these compounds was performed by HPLC, using 2,2-bis-(4-hydroxyphenyl)-propane as an internal standard. Tyrolobibenzyls A-F were only detected in samples from Scorzonera humilis, while chlorogenic acid and 3,5-dicaffeoylquinic acid were detected in all samples investigated. In contrast, caffeoyl tartaric acid and cichoric acid were not detectable in any member of the subtribe Scorzonerinae.     

Quantitative determination of flavonoid content in the aerial part of Baical scullcap (<Emphasis Type="Italic">Scutellaria baicalensis</Emphasis> Georgi)

A pharmacognostic study of aerial parts of Scutellaria baicalensis Georgi (Lamiaceae family) has been carried out. A merchandising analysis has been performed to determine the basic quality parameters of S. baicalensis. A chemical composition analysis has revealed the presence of organic acids, free carbohydrates, polysaccharides, amino acids, alkaloids, flavonoids, phenolic acids, anthocyanins, tannins, photosynthetic pigments, lipids, and triterpene compounds. Ethyl acetate and ethanol fractions, extracted from the aerial parts of S. baikalensis, have shown a significant antiradical activity.