白术多糖指纹图谱和抗氧化活性的谱效关系分析北大核心CSCD

将高效液相色谱(HPLC)指纹图谱、抗氧化活性研究与多元统计分析相结合,对不同产地的38批白术多糖进行质量评价.以三氟乙酸水解白术多糖,用1-苯基-3-甲基-5-吡唑啉酮进行衍生化,采用高效液相色谱法测定其中单糖的衍生物,得到指纹图谱.以1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除能力、羟自由基清除能力和Fe^(3+)总还原能力为指标测定抗氧化活性,并对结果进行相似度分析、层次聚类分析和偏最小二乘法-判别分析等多元统计分析.结果表明,白术多糖指纹图谱鉴别了5个共有峰,分别为鼠李糖、半乳糖醛酸、葡萄糖、半乳糖和阿拉伯糖.基于多元统计分析,浙江、安徽、河北和四川的白术样品分离显著.此外,选择半乳糖醛酸和半乳糖作为潜在的化学标记物,DPPH自由基清除能力对应的抗氧化活性可作为辅助鉴别的候选检测指标.     

淫羊藿多糖的分子特征及免疫活性研究

用超声复合酶提取、离子交换凝胶分离、分子筛凝胶纯化得到3个淫羊藿叶多糖组分(EPs-1,EPs-2和EPs-3).3个多糖组分的分子特征通过气相色谱、高效凝胶渗透色谱进行了表征,并采用体外淋巴细胞增殖和巨噬细胞吞噬活性实验对多糖的免疫活性进行了评价.3个多糖组分EPs-1,EPs-2和EPs-3的总糖含量分别为90.36%,94.51%和89.19%.EPs-1,EPs-2和EPs-3主要由半乳糖醛酸(GalA)、半乳糖(Gal)、鼠李糖(Rha)、木糖(Xyl)、阿拉伯糖(Ara)和甘露糖(Man)组成,其平均相对分子质量分别为81.64×10~3,60.53×10~3,21.85×103;3个多糖都能够促进脾淋巴细胞增殖和激活巨噬细胞活性.这些结果说明淫羊藿多糖可以作为天然的免疫活性调节剂应用于医药和功能食品.     

高效液相色谱-电喷雾质谱法用于茶多糖蛋白的纯度和相对分子质量的测定

应用Sephadex G100凝胶色谱方法从江西产粗老茶叶中提取纯化得到茶多糖蛋白(TGC)。通过高效液相色谱法对其纯度进行了分析,表明其为均一组分,进而应用凝胶法和高效液相色谱 电喷雾质谱法测得该茶多糖蛋白的相对分子质量为51 500。     

沙蒿籽水溶性胶多糖ASPI-A的结构与免疫活性的初步研究

从沙蒿籽中提取出水溶性胶多糖,经柱色谱分离纯化得到一种中性多糖组分ASPI-A.采用高效凝胶渗透色谱法(HPGPC)测定其为均一性多糖,平均分子量为5.42×104Da.经IR,GC部分酸水解、甲基化分析等方法对该多糖的化学结构进行了表征.结果表明,该多糖由阿拉伯糖、甘露糖、葡萄糖及半乳糖组成,其物质的量的比为1∶2.8∶4.9∶1.9.ASPI-A为多分支结构,以(1→4)-β-Glc构成主链,部分葡萄糖C6存在分支,由甘露糖以-4)Man(1-连接在葡萄糖C6位,Glc(1-和Gal(1-连接在甘露糖C4位构成.免疫活性实验结果表明,ASPI-A在10～50μg·mL-1浓度范围内对ConA诱导的小鼠T淋巴细胞增殖反应具有促进作用.     

响应面法优化微波提取夏枯草多糖及其抗氧化活性

以夏枯草多糖为研究对象,在单因素实验的基础上,采用响应面法对夏枯草多糖的微波提取工艺进行优化,测定其抗氧化活性。结果表明,夏枯草多糖的最佳提取条件为:液料比29∶1(mL·g~(-1)),乙醇体积分数68%,微波功率295W,微波时间8min,在该条件下夏枯草多糖得率为5.28%,与理论值(5.19%)的相对误差为1.73%。在此条件下得到的多糖提取物具有较好体外抗氧化活性,对DPPH自由基、羟基自由基、超氧阴离子具有不同的清除能力,半数抑制浓度IC_(50)分别为0.58、0.49和1.19mg·mL~(-1 )。     

山药多糖的制备及其体外抗氧化活性

提取山药粗多糖并进行精制,分析了山药多糖的单糖组成,并研究了山药多糖的体外抗氧化活性.结果表明,山药精制多糖纯度较高,由鼠李糖、阿拉伯糖、甘露糖、葡萄糖和半乳糖组成.体外抗氧化活性测试结果表明,山药多糖具有一定的还原能力,对羟自由基具有较强的清除能力,并对小鼠肝匀浆自氧化有明显的抑制作用.因此,山药多糖具有较好的抗氧化活性,可作为潜在的抗氧化剂或抗衰老药物进行深入研究和开发.     

蒙药漏芦花多糖提取工艺及其抗氧化抗菌活性研究

本文优化了蒙药漏芦花多糖的提取工艺,并评价其抗氧化和抗菌活性。以超声功率、超声温度、超声时间和浸泡时间为影响因素,多糖提取率为评价指标,在单因素实验的基础上利用正交试验优化提取工艺,测定漏芦花多糖对DPPH自由基、羟基自由基清除效果,检测其抗氧化活性,涂布平板法测定多糖抗菌活性。超声波辅助法提取蒙药漏芦花多糖的最佳工艺条件为超声功率180W,超声温度70℃,超声时间30min,浸泡时间40min,在此条件下多糖得率为1.125%。抗氧化实验表明,漏芦花多糖浓度在0.5～2.5mg·mL~(-1)范围内,随着漏芦花多糖浓度增加,总还原能力不断增强;其体外清除DPPH自由基能力也随浓度增大而增强,清除率最高达72.98%;当多糖浓度为1.5mg·mL~(-1)时,漏芦花多糖体外清除羟基自由基能力最强,为7.24%。漏芦花多糖浓度为12.8mg·mL~(-1)时,对沙门氏菌的抑菌圈直径为9.72mm。超声法提取蒙药漏芦花多糖操作简便、准确、灵敏、重现性好,漏芦花多糖抗氧化能力良好,且对沙门氏菌有一定的抑菌效果。     

杏鲍菇多糖WPP2的结构表征及抗肿瘤活性

采用热水浸提法从杏鲍菇中提取粗多糖, 经纯化得到一种新的多糖WPP2.通过紫外光谱、色谱、质谱、核磁共振、红外光谱、环境扫描电子显微镜(ESEM)和原子力显微镜(AFM)等技术相结合的方法, 对WPP2结构进行了表征, 并对其体外抗氧化和抗肿瘤活性进行了初步探讨.结果表明, WPP2的平均分子量为4.499×10⁵, 主要由Glc组成, 每个重复单元存在2条支链,→1,2,3)-β-D-Manp和→1,2,6)-β-D-Manp位于支链位点, 支链由→1,6)-β-D-Glcp和→1,6)-β-D-Galp构成, 非还原末端基为→1)-β-D-Glcp, 主链主要由→1,3)-β-D-Glcp,→1,6)-β-D-Galp和→1,3)-β-D-Manp糖残基组成.刚果红实验结果表明其具有三螺旋结构; 用ESEM和AFM首次在纳米尺度观察到WPP2具有多分枝结构; 活性实验结果表明WPP2具有一定的抗氧化和抗肿瘤活性.     

佛手多糖的化学组成及体外抗氧化活性研究

佛手经热水提取和乙醇沉淀,得佛手多糖粗品(BP).BP经Servag法除蛋白,用DEAE离子交换柱梯度洗脱分离得到BP1和BP2两个组分,经凝胶色谱和SDS-聚丙烯酰胺凝胶电泳检验为均一组分.用凝胶渗透色谱法测得BP1和BP2的重均分子量分别为17773和65589.薄层色谱和高效液相色谱分析表明,BP1和BP2均由鼠李糖、甘露糖、葡萄糖、半乳糖和木糖组成.采用化学发光法在多种化学模拟体系中研究了佛手多糖清除活性氧的作用,观察了佛手多糖对HO^.导致DNA链损伤的抑制作用.结果表明,佛手多糖能有效地清除O₂^-.和HO^.等活性氧,对DNA链具有良好的保护作用.     

梁王茶茎皮多糖提取工艺的优化及其抗氧化活性研究

本文为优化梁王茶茎皮多糖(PND)的提取工艺,并评价其抗氧化活性,以多糖提取率为评价指标,在单因素实验的基础上采用响应面法对超声时间、超声温度和超声功率三个影响梁王茶多糖提取工艺的主要因素进行优化;再通过DPPH、ABTS自由基清除实验和FRAP法评估其抗氧化能力。结果表明,超声提取梁王茶茎皮多糖的最佳工艺条件为超声时间120 min、超声温度60℃、超声功率125 W、浸泡时间20 min、液料比10∶1及乙醇浓度80%,该条件下多糖提取率为4.780%。抗氧化实验表明,梁王茶茎皮多糖浓度在1～10 mg·mL~(-1)范围内,随多糖浓度增加DPPH自由基清除能力增强,IC_(50)值为7.591±0.205 mg·mL~(-1);以Trolox当量来表示其ABTS自由基清除能力为1.464±0.194 mmol Trolox/g PND;以Fe~(2+)当量来表示其还原能力为0.302±0.020 mmol Fe~(2+)/g PND。     

Optimization of extraction process and the antioxidant activity spectrum–effect relationship of Angelica dahurica

Despite the large number of studies indicating that Angelica dahurica has strong antioxidant capacity, there are no clear details on the specific antioxidant components involved. In this study, the chromatograms and antioxidant activity of A. dahurica were obtained by gas chromatography–mass spectrometry (GC–MS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and ferric ion reducing antioxidant power (FRAP) methods. The factors affecting free radical scavenging were investigated under different extraction conditions, on the basis of the single-factor experiment. The results showed that the optimum conditions for the DPPH method were ultrasonic extraction, using 80% methanol as extract the extraction solvent, a 20:1 (ml/g) ratio of liquid to material and an extraction time of 30 min. Furthermore, the spectrum–effect relationship between the GC–MS chromatograms and the antioxidant effect of A. dahurica was established to evaluate the antioxidant components of A. dahurica using multiple data analysis methods. Isoimperatorin and byakangelicol made the greatest contribution to scavenging DPPH free radicals and ferric-reducing antioxidant power. This result may provide the basis for developing new and effective products based on the antioxidant ingredients of A. dahurica.     

Extraction of flavonoids from Rhodiola sachlinesis A. Bor by UPE and the antioxidant activity of its extract

Rhodiola sachlinesis, A. Bor is one of the most popular traditional Chinese medicines and has been proved to have many effective compounds, such as flavonoids, anthraglycosides, essential oil with cinnamic aldehyde and citral and organic acids. In this article, a new method of ultrahigh pressure extraction (UPE) was used to extract flavonoids from R. sachlinesis. Uniform Design was employed to get the optimum extraction conditions. The optimum UPE conditions were as follows: pressure was 500 MPa; ethanol concentration was 40%; solid/liquid ratio (g mL(-1)) was 1 : 70. The optimum extraction yield of flavonoids was 52.33 mg g(-1). The antioxidant activity of the crude extract was tested with DPPH assay. It showed a higher activity, compared with tertiary butyhydroquinone (TBHQ) at the same concentration (1 mg mL(-1)).     

Antioxidant activity guided separation of major polyphenols of marjoram (Origanum majorana L.) using flash chromatography and their identification by liquid chromatography coupled with electrospray ionization tandem mass spectrometry†

Marjoram extracts have been separated into polar and nonpolar parts using liquid–liquid extraction. Both polar and nonpolar parts of the extracts were further fractionated by flash chromatography. The obtained fractions (90 polar and 45 nonpolar fractions) were investigated for their antioxidant activities by 2,2‐diphenylpicrylhydrazyl and ferric ion reducing antioxidant power assays. A direct, positive, and linear relationship between antioxidant activity and total phenolic content of the fractions was observed. Based on antioxidant and total phenolic content data, the three fractions with the high antioxidant activities from polar and nonpolar part of the extract were analyzed for their constituent polyphenols by liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Compounds were identified by matching the mass spectral data and retention time with those of authentic standards. Identification of the compounds for which there were no “in‐house” standards available was carried out by accurate mass measurement of the precursor ions and product ions generated from collision‐induced dissociation. Rosmarinic acid was found to be the strongest antioxidant polyphenol conferring the highest antioxidant activity to fractions 47 and 17 of polar and nonpolar part of the extract, respectively. The identification of the rosmarinic acid was further confirmed by ¹H NMR spectroscopy.     

Combined Ultrahigh Pressure Extraction and High-Speed Counter-Current Chromatography for Separation and Purification of Three Glycoside Compounds from Dendrobium officinale Protocorm

As an alternative to Dendrobium candidum, protocorm-like bodies (PLBs) of Dendrobium candidum are of great value due to their high yield and low cost. In this work, three glycoside compounds, β-D-glucopyranose 1-[(E)-3-(4-hydroxyphenyl)-2-propenoat] (I), β-D-glucopyranose 1-[(E)-3-(3, 4-dihydroxyphenyl)-2-propenoat] (II), and 1-O-sinapoyl glucopyranoside (III), were extracted and isolated by ultrahigh pressure extraction (UPE) coupled with high-speed counter-current chromatography (HSCCC) from PLBs of D. officinale. First, the target compounds were optimized and prepared with 50% ethanol solution at a 1:30 (g/mL) solid/liquid ratio in 2 min under 300 MPa by UPE. Then, the crude extract was chromatographed with a silica gel column, and primary separation products were obtained. In addition, the products (150 mg) were separated by HSCCC under the solvent system of MTBE-n-butyl alcohol-acetonitrile-water (5:1:2:6, v/v/v/v), yielding 31.43 mg of compound I, 10.21 mg of compound II, and 24.75 mg of compound III. Their structures were further identified by ESI-MS, ¹H NMR, and ¹³C NMR. The antioxidant results showed that the three compounds expressed moderate effects on the DPPH· scavenging effect. Compound II had the best antioxidant capacity and its IC₅₀ value was 0.0497 mg/mL.     

Analysis of essential oils from Voacanga africana seeds at different hydrodistillation extraction stages: chemical composition,antioxidant activity and antimicrobial activity

In this study, essential oils from Voacanga africana seeds at different extraction stages were investigated. In the chemical composition analysis, 27 compounds representing 86.69–95.03% of the total essential oils were identified and quantified. The main constituents in essential oils were terpenoids, alcohols and fatty acids accounting for 15.03–24.36%, 21.57–34.43% and 33.06–57.37%, respectively. Moreover, the analysis also revealed that essential oils from different extraction stages possessed different chemical compositions. In the antioxidant evaluation, all analysed oils showed similar antioxidant behaviours, and the concentrations of essential oils providing 50% inhibition of DPPH-scavenging activity (IC₅₀) were about 25 mg/mL. In the antimicrobial experiments, essential oils from different extraction stages exhibited different antimicrobial activities. The antimicrobial activity of oils was affected by extraction stages. By controlling extraction stages, it is promising to obtain essential oils with desired antimicrobial activities.     

Separation of Cytidine 5′-triphosphate Biosynthesized from Cytidine 5′-monophosphate on Ion-exchange Resin and HPLC Analysis of Cytidine Compounds

Conditions were studied in the biosynthesis of cytidine 5′-triphosphate (CTP) from cytidine 5′-monophosphate (CMP). A 201 × 7 anion ion-exchange resin was applied for the separation of CTP from CMP. Adsorption isotherm and elution conditions (eluant, eluant concentration, flow rate, sample volume loaded) were investigated. At the same time, a new high-performance liquid chromatography on an anion ion-exchange column WAX-1 with UV detector at 260 nm was developed to measure CMP, cytidine 5′-diphosphate (CDP), and CTP. The retention time for CMP, CDP, and CTP are 0.723, 1.448, and 4.432 min, respectively. This new rapid high-performance liquid chromatography (HPLC) method for the analysis of cytidine compounds in biological sample has a wide linear range with high precision and repeatability.     

Determination of polyphenols in three Capsicum annuum L. (bell pepper) varieties using high-performance liquid chromatography-tandem mass spectrometry: their contribution to overall antioxidant and anticancer activity

A mixture of polyphenol components was isolated from the fruits of C. annuum L. cv. Cupra, C. annuum L. cv. Orange glory, and C. annuum L. cv. ST4712 (CLST), via 70% methanol extraction followed by column chromatography over silica gel. The polyphenol components of the mixture were analyzed via HPLC-MS/MS and compared with the reported data. Three cinnamic acid derivatives and five flavonoid components in the fruits of the three varieties were identified for the first time in this study. The antioxidant activity and anticancer effect of the polyphenol mixtures of the three fruits were determined. The antioxidant and anticancer activities of CLST were substantially higher than those of C. annuum L. cv. Cupra and C. annuum L. cv. Orange glory. The high activities of CLST were attributed to the much higher concentration of quercetin derivatives in CLST.     

Optimization of Extraction Conditions for Flavonoid Composition and Antioxidant Activity of Radix Scutellariae

Microwave, ultrasonic, and reflux extraction were compared to provide an optimized method for flavonoids from Radix Scutellariae including the antioxidant activity of the extracts. The antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl and oxygen radical absorbance capacity assays. Baicalin, wogonoside, baicalein, wogonin, and oroxylin A were quantified using ultra-high performance liquid chromatography. For microwave extraction, with a ten minutes treatment, the extraction efficiencies of the analytes were higher than treatments by refluxing for 180 minutes and sonication for sixty minutes. In addition, the antioxidant activity of the microwave extracts was slightly higher than the extracts obtained by the other methods. Microwave extraction conditions were further optimized by a single-factor experiment and the optimum conditions were 50 percent ethanol–water (volume by volume), an extraction temperature of 100 degrees celsius, an extraction time of ten minutes, and a sample to solvent ratio of 1:50. This study combines extraction, phytochemistry, and bioactivity to screen the most efficient extraction procedure for flavonoids from Radix Scutellariae.     

Flavonoid profiling in three citrus varieties native to the Republic of Korea using liquid chromatography coupled with tandem mass spectrometry: contribution to overall antioxidant activity

A mixture of flavonoid components was isolated from the fruit peel of three varieties of citrus native to Republic of Korea, Citrus leiocarpa Hort. ex Tanaka (CLHT), Citrus aurantium L. (CAL) and Citrus erythrosa Hort. (CEH), via 70% methanol extraction followed by ethyl acetate elution over a silica gel cartridge. The flavonoid components of the mixture were analyzed via high‐performance liquid chromatography–tandem mass spectrometry (HPLC‐MS/MS) in positive‐ion mode and a comparison of the reported data. Among 17 characterized components, two flavanones, four flavones and two coumarin derivatives in the fruit peel of the three varieties were identified for the first time. The individual characterized components were quantified via HPLC‐UV. The flavanones dominated in CAL, whereas the flavones prevailed in CLHT and CEH. The antioxidant activity of the flavonoid mixture of the fruit peel was determined via DPPH^?, ABTS^?+ and reducing power assays. The antioxidant activity of CEH and CAL was greater than that of CLHT. Copyright © 2011 John Wiley & Sons, Ltd.     

Comparison of green extraction methods with conventional extraction method for extract yield,L-DOPA concentration and antioxidant activity of Mucuna pruriens seed

ABSTRACT

Mucuna pruriens is a plant of Fabaceae family. Seed of M. pruriens is considered as a rich source of levo-3,4 dihydroxyphenylalanine (L-DOPA), a non-protein phenolic amino acid. In the present study, three different extraction methods were compared for extract yield, concentration of bioactive compounds such as total phenol, L-DOPA and antioxidant capacity. Extracts were prepared using water acidified with hydrochloric acid (0.1?N) by conventional method of refluxing as well as two green methods namely ultrasound and microwave assisted solvent extraction. A rapid and qualified high-performance liquid chromatography method was also developed for quantification of L-DOPA in different extracts. Among the three extraction methods, microwave assisted extraction provided the best results for yield and quality of M. pruriens extract in much shorter time in comparison to refluxing method of extraction.