普洱茶的抗氧化酚类化学成分的研究

从云南省双江县勐库产的普洱茶中分离得到11个化合物,分别为:(-)-没食子儿茶素(GC,1),(-)-表儿茶素(EC,2),(+)-儿茶素(C,3),杨梅素(4),没食子酸(5),山奈酚(6),山奈酚-3-O-β-D-葡萄糖甙(7),山奈酚-3-O–芦丁糖甙(8),槲皮素(9),槲皮素-3-O-β-D葡萄糖甙(10)以及2,5-二羟基苯甲酸(11)。其中,化合物6~11为首次从普洱茶中分离得到。DPPH自由基清除活性测试结果表明,化合物2、3、5的活性与阳性对照品抗坏血酸接近。化合物的结构与其活性的关系比较分析表明,简单儿茶素(2,3)和简单酚类化合物(5)的抗氧化活性较高,与阳性对照品抗坏血酸接近;黄酮类化合物(4,6,9)次之,黄酮类配糖体(7,8,10)及化合物11则较差。     

大麦花后四种主要黄酮物质含量的动态变化

为了解开花后大麦不同器官黄酮类物质的变化,以富含黄酮的大麦品系94-19-1为材料,在开花后10、25和40d时,分析测定了其根、茎、叶和穗中儿茶素、杨梅素、槲皮素和山奈酚四种主要黄酮类物质的含量。结果表明,在开花10~40d,四种黄酮类物质的含量在根、茎、叶和穗部均随着时间的变化而变化,且趋势不同,其总含量在根和叶中以花后25d最高,在茎和穗部中呈增加趋势。不同器官中四种黄酮物质含量在同一时期均存在差异,且其总含量都以穗部最高。     

药食同源植物鼠曲草中6种黄酮类成分的含量测定

建立了高效液相色谱法同时测定鼠曲草中6种黄酮类成分:槲皮素,木犀草素,芹菜素,山奈酚,金丝桃苷,木犀草素-4’-O-β-D-葡萄糖苷含量的方法。样品用80%甲醇超声提取,采用HPLC法检测,色谱柱:Agilent Eclipse XDB C18Column (250×4.6 mm I.D.,5μm);流动相:乙腈-0.1%甲酸梯度洗脱;流速:1.0 mL/min;柱温:30℃;检测波长:360 nm。结果表明,在一定的浓度范围内6种黄酮的浓度与峰面积线性关系良好,相关系数R~2为0. 9997～0. 9999,样品的加样回收率为95. 20%～108. 5%,RSD均≤2. 8%。本方法简便、快捷、精密度高、重现性好,可用于鼠曲草中黄酮类成分的含量测定。研究结果为明确鼠曲草作用的物质基础以及制定质量标准提供很好的依据。     

柳蒿化学成分的含量测定及肝损伤保护作用的研究

目的建立HPLC同时测定柳蒿(Artemisia integrifolia Linn.)中绿原酸、芦丁、木犀草苷、槲皮素含量的方法,并研究柳蒿提取液对肝脏的保护作用,探讨其可能机理。方法采用高效液相色谱法。色谱柱为Inertsil ODS-3柱,流动相为乙腈-0.2%磷酸水溶液(梯度洗脱),流速为1.0 mL·min~(-1),检测波长270 nm,柱温25℃,进样量为10μL;60只雄性小鼠随机分为6组,每组10只,除正常组外,其余各组均腹腔注射0.1%的CCl_4橄榄油溶液致小鼠急性肝损伤,测定小鼠血清中谷丙转氨酶(ALT)和谷草转氨酶(AST)活力;肝组织中丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-Px)、总抗氧化能力(T-AOC)和总超氧化物歧化酶(T-SOD)。结果绿原酸、芦丁、木犀草苷、槲皮素检测进样量线性范围分别为1.015 2～16.243 2μg(r=0.999 9),0.257 1～4.113 6μg(r=0.999 9),0.081 6～1.305 6μg(r=0.999 8),0.027 3～0.436 8μg(r=0.999 9);精密度、稳定性、重复性试验的RSD2.0%;加样回收率分别为98.73%～100.42%(RSD=0.52%,n=5),95.64%～102.07%(RSD=1.52%,n=5),94.05%～99.79%(RSD=1.73%,n=5),96.22%～101.89%(RSD=2.45%,n=5)。柳蒿提取液可明显抑制CCl_4致小鼠肝损伤后血清中ALT和AST升高,肝组织中MDA含量升高,提高肝组织中T-SOD、GSH-PX、T-AOC活性。结论建立的HPLC方法,简便、精确、灵敏度高,可用于柳蒿药材中4种成分含量的同时测定。柳蒿对CCl_4所致小鼠急性肝损伤具有保护作用。该结果可为今后柳蒿的开发利用和深入研究提供一定的参考。     

不同茶树品种中黄酮苷含量的测定

本研究采用液相质谱技术分离、鉴定了茶叶中的12种黄酮苷类化合物,包括1种芹菜素苷、2种杨梅素苷、5种槲皮素苷和4种山奈酚苷。结合标准品及高效液相色谱系统,测定了8种不同茶树品种中黄酮苷类化合物的含量。结果显示,不同茶树品种中黄酮苷含量分布广泛,以槲皮苷为主。紫芽品种中12种黄酮苷含量最高,达6.12 mg/g;福建水仙品种中含量最低,仅2.31 mg/g,茶树品种间存在显著性差异(P<0.05)。     

分光光度法测定茶叶中总黄酮含量

黄酮类与儿茶素类物质对茶叶感官品质和生物活性起重要作用,因此建立一种茶叶中总黄酮(包括黄酮类和儿茶素类)含量的测定方法很有必要.采用70％甲醇提取茶样,以芦丁为对照品,利用亚硝酸钠-硝酸铝-氢氧化钠溶液显色,在510 nm下测定吸光度,建立测定茶叶中总黄酮含量的分光光度法,并对其进行方法学考察.应用该法测定了绿茶、白茶、乌龙茶和红茶4个茶类15个茶样中总黄酮含量,采用福林酚法测定其茶多酚含量,并比较二者相关性.结果表明,芦丁质量浓度在0.2～1.0 mg·mL-1范围内与吸光度线性关系良好,回归方程为Y=1.2465X+0.0074(R2=0.9997).方法学考察结果表明,该方法精密度、重复性和稳定性的吸光度RSD为1.17％、2.92％和6.01％,平均加标回收率为84.35％(RSD=4.15％).15个茶样中总黄酮含量范围为5％～10％,总黄酮含量规律为:绿茶、白茶>乌龙茶>红茶.福林酚比色法测得茶多酚含量范围为7％～15％.双变量相关性分析显示,总黄酮含量与茶多酚含量呈极显著正相关,Pearson相关系数达0.874.由此表明,该方法操作简便,精密度、重复性与稳定性好,可用于茶叶总黄酮含量测定.     

RP-HPLC测定委陵菜中槲皮素含量研究

[目的]建立测定委陵菜中槲皮素含量的方法.[方法]采用Zorbax SB C18柱(250mm×4.6 mm,5μm),流动相为乙腈-水-磷酸(50∶50∶0.04),检测波长为360 nm,测定委陵菜中槲皮素含量.[结果]槲皮素在0.2～2.1 μg/mL(r=-0.999 7)范围内与峰面积呈良好的线性关系(n=6);样品平均回收率(n=9)为99.4％,RSD为2.57％.[结论]建立的方法简便、快速、准确,重现性好,可用于委陵菜中槲皮素含量的测定.     

茶多酚中儿茶素类的HPLC分析方法学考察

本文建立了一种非梯度洗脱的儿茶素HPLC定性定量分析方法 ,同时对茶多酚中的四种主要儿茶素(EC ,EGCG ,ECG ,EGC)考察了其方法学。得到最佳色谱条件为 :ODS (5 μm ,4 6× 2 5 0mm)柱 ,以重蒸水∶乙睛∶乙酸乙酯 =86∶12∶2 (v v v)为流动相 (浓硫酸调pH值至 3 0～ 4 0 ) ,流速为 1 0ml min ,UV检测波长 2 80nm。探讨了分离测定条件并验证其精密度及方法的稳定性     

红茶主要多酚类化合物的HPLC分析

以正山小种、坦洋工夫等16种不同产地的典型红茶为供试材料,采用HPLC法分析比较了红茶中主要多酚类物质含量的差异.结果表明,红茶主要多酚类物质含量差异较大,其中儿茶素总量、没食子酸、绿原酸、黄酮醇及其苷类物质的含量分别为4.50-41.65mg/g,1.139 ～ 3.689mg/g,0～ 530mg/kg,0.63 ～ 4.48mg/g,苏红工夫、海南红茶、台湾红茶、越红工夫中的酯型儿茶素较高;英德红茶、台湾红茶中的黄酮醇类物质含量较高;正山小种的多酚类物质含量较低,且种类少.槲皮素、杨梅素苷类物质仅在部分样品中有检出,含量分别不高于3.00mg/g和1.50mg/g,芹菜素未被检测出.根据红茶中主要多酚类化合物含量的差异将16种红茶划分为3个类群.     

黄麻韧皮纤维活性物质鉴定及抑菌效果分析

采用溶剂法从黄麻韧皮纤维中提取黄酮、多糖、生物碱3种成分,并对提取物的化学组分及抑菌效果进行测定分析。结果表明,3种提取物中总黄酮、总多糖、总生物碱含量分别为17.36 mg/g、3.57 mg/g、61.01μg/g。高效液相色谱法(HPLC)检测出黄酮类提取物主要包括异槲皮素(167.47μg/g)、槲皮素(12.35μg/g)、木犀草素(6.41μg/g)、山奈酚(6.26μg/g)等;多糖类提取物中的单糖组分有半乳糖(0.41 mg/g)、半乳糖醛酸(0.43 mg/g)、阿拉伯糖(1.03 mg/g)等;生物碱类提取物主要组分为盐酸小檗碱(9.97μg/g)。纸片扩散法、二倍稀释观察法、扫描电镜分析显示,3种提取物对金黄色葡萄球菌、大肠杆菌、痢疾杆菌均能产生不同程度的抑制效果。综上,黄麻韧皮纤维中的活性物质较为丰富,且具有良好的抑菌性能。     

The Content of Dietary Fibre and Polyphenols in Morphological Parts of Buckwheat (<Emphasis Type="Italic">Fagopyrum tataricum</Emphasis>)

In this report, we presented the profile of polyphenolic substances in flowers, leaves, stalk and roots of Fagopyrum tataricum estimated by using RP–UHPLC–ESI-MS equipment (reversed-phase ultra-high-performance liquid chromatography electrospray ionisation mass spectrometry). The neutral detergent fibre, acid detergent fibre, acid detergent lignin, cellulose and hemicellulose were also determined. Flowers, leaves, stalk and roots showed varying levels of dietary fibre and polyphenols. The highest content of neutral and acid detergent fibre were found in the roots (63.92 and 45.45% d.m., respectively) while the most rich in phenolic compounds were flowers (4.8 mg/1 g d.m.). Root and stalk contained the highest level of cellulose, 38.70 and 25.57% d.m., respectively. Among the investigated polyphenolic substances such as: 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 4-hydrobenzoic acid, caffeic acid, catechin, chlorogenic acid, fagopyrin, ferulic acid, myricetin, gallic acid, isovanilic acid, isovitexin, kaempferol, luteolin, p-coumaric acid, procyanidin B2, quercetin, quercetin 3-D galactoside, rutin, syringic acid and vitexin, we observed that the contents of rutin and chlorogenic acid were the highest. We found some correlation between dietary fibre fractions and individual phenolic substances. The levels of acid detergent fibre (ADF), cellulose and hemicellulose were negatively correlated with isovitexin, kaempferol, vitexin, fagopyrin, caffeic acid and procyanidin B2 content. In this investigation, two solvents (water and methanol) were estimated regarding their extraction efficiency of phenolic compounds. Taking these results into consideration, we recommend using methanol as the extractor to isolate chlorogenic acid, fagopyrin, kaempferol, procyanidin B2, quercetin, quercetin 3-D-galactoside, rutin, vitexin, and water for other investigated polyphenolic substances obtained from Fagopyrum tataricum.     

茶叶儿茶素对发根农杆菌的抑制作用及抗酚菌株筛选研究

本文研究了茶叶儿茶素对发根农杆菌的抑制作用并进行了抗酚菌株的筛选。结果表明：儿茶素（TC80）对发根农杆菌有明显的抑制作用,其MIC90为25~100 μg/ml,这阐明了茶树中富含儿茶素等多酚类是制约农杆菌介导法对茶树进行遗传转化的关键因子。通过抗酚筛选获得的抗酚菌株R1000AP,其抗酚性提高10~40倍,其诱导茶树的发根频率提高46.5%（P<0.05）。     

Polyphenolics Profile, Antioxidant and Radical Scavenging Activity of Leaves and Stem of Raphanus sativus L.

Aerial parts (leaves and stem) of Raphanus sativus, which are usually discarded were found to possess potent antioxidant and radical scavenging activity, as measured by standard antioxidant assays. Methanolic and acetone extracts of R. sativus leaves had total polyphenolic content of 86.16 and 78.77 mg/g dry extract, which were comparable to the traditional rich sources such as green tea and black tea. HPLC identification of polyphenolics indicated the presence of catechin, protocatechuic acid, syringic acid, vanillic acid, ferulic acid, sinapic acid, o-coumaric acid, myricetin, and quercetin in leaves and stem. Among the different extraction solvents, methanolic extract of leaves and stem showed potent reductive capacity, significantly inhibited linoleic acid peroxidation and displayed metal chelating activity. Further, they scavenged free radicals effectively with IC₅₀ (half maximal inhibitory concentration) of 31 and 42 μg/ml for DPPH radical, 23 and 52 μg/ml for superoxide radical, 67 and 197 μg/ml for hydrogen peroxide, and 56 and 62 μg/ml for nitric oxide, respectively. Leaves showed most potent antioxidant and radical scavenging activity as compared to stem, which may be accounted for the high polyphenolic content. Leaves and stem of R. sativus, often under-utilized part of this vegetable, thus possessed considerable amount of polyphenolics. Hence, it should be regarded as a potential source of natural antioxidants and could be effectively employed as an ingredient in health or in functional food.     

The Phenolic Contents and Antioxidant Activities of Infusions of <Emphasis Type="Italic">Sambucus nigra</Emphasis> L.

The aim of this work was to evaluate the antioxidant potential of teas prepared from twenty-four commercially available berries and flowers of Sambucus nigra L. in relation to their phenolic profile, as reflected by the most representative phenolic acids (caffeic, chlorogenic, p-coumaric, ferulic, gallic and syringic acids); flavonols (quercetin, kaempferol, myricetin and rutin); and total phenolic (TPC), phenolic acid (TAC) and flavonoid (TFC) contents. The infusions prepared from elderflowers contained more abundant phenolic compounds than the elderberry infusions. The TPC of these infusions ranged from 19.81 to 23.90 mg of gallic acid equivalents/g dry weight of sample (GAE/g DW) for elderberries and from 15.23 to 35.57 mg GAE/g DW for elderflowers, whereas the TFC ranged from 2.60 to 4.49 mg of rutin equivalents/g dry weight of sample (RUTE/g DW) in elderberry infusions and from 5.27 to 13.19 mg RUTE/g DW in elderflower infusions. Among the phenolic compounds quantified in this study, quercetin (2.07–9.48 mg/g DW) and myricetin (1.17–9.62 mg/g DW) had the highest concentrations in the teas prepared from berries and flowers, respectively. Moreover, the antioxidant potential of elder infusions assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and ferric reducing antioxidant power (FRAP) assays revealed that the teas prepared from flowers had higher mean DPPH and FRAP activities than the teas prepared from berries. Therefore, elder beverages could be important dietary sources of natural antioxidants that contribute to the prevention of diseases caused by oxidative stress.     

贵州绿茶中咖啡碱和儿茶素含量分析

对贵州省243份绿茶样品中咖啡碱和儿茶素类物质采用高效液相色谱方法进行检测。结果表明：贵州省绿茶中儿茶素含量范围为9.14%~27.28%,平均含量15.71%;咖啡碱含量为1.08%~3.33%,平均含量2.24%。各地区茶叶儿茶素品质指数多数为1000~2000,其中黔南地区的最高为1975.51;各地区的儿茶素苦涩味指数主要在8.00~17.04之间,黔西南地区的苦涩味指数最低为8.00。据此分析可得,贵州绿茶具有很高的利用价值,春茶适合开发高品质的名优茶,秋茶适合用于茶叶深加工或有效成分的提取。     

Accumulation of Polyphenolic Compounds and Osmolytes under Dehydration Stress and Their Implication in Redox Regulation in Four Indigenous Aromatic Rice Cultivars

Present work was undertaken to screen some drought tolerant indigenous aromatic rice cultivars (IARCs), commonly cultivated in West Bengal, India, based on their capacity to produce osmolytes, redox-sensitive phenolic acids and flavonoids, as contrivances for redox-regulation under drought stress. Polyethylene glycol induced post imbibitional dehydration stress mediated changes in redox regulatory properties of the germinating seeds of the four IARCs (Jamainadu, Tulaipanji, Sitabhog, Badshabhog), which were assessed in terms of changes in prooxidant accumulation (in-situ localization of reactive oxygen species (ROS) by confocal microscopy, DCFDA (2′,7′-dichlorofluorescin diacetate) oxidation, O₂⁻ and H₂O₂ accumulation), cumulative antioxidative defense (radical scavenging property and total thiol content), ROS scavenging phenolic acids (gallic acid, protocatechuic acid, gentisic acid, para-hydroxy benzoic acid, chlorogenic acid, caffeic acid, syringic acid, salicylic acid, sinapic acid and p-coumaric acid) and flavonoids (catechin, naringin, rutin, quercetin, kaempferol, myricetin and apigenin). The capability of germinating seeds to accumulate osmolytes (like glycinebetaine, proline, soluble carbohydrates and K⁺ ion) and polyphenolic compounds was also correlated with their corresponding redox status and redox biomarkers (conjugated diene, hydroperoxide, thiobarbituric acid reactive substances and free carbonyl content) produced under the same conditions. The results in general showed that accumulation of osmolytes along with the redox-sensitive phenolics and flavonoids conferred the ability to maintain the redox homeostasis under drought stress for the tolerant IARCs (Badshabhog and Tulaipanji).     

Transparent Polycaprolactam Electrospun Nanofibers Doped with 1,10-phenanthroline Optical Sensor for Colorimetric Determination of Iron (II) and Vitamin C

A novel optical chemical sensor based on a transparent electrospun nanofibrous scaffold, composed of polycaprolactam (PA6) and 1,10-phenanthroline (Phen), deposited on a glass slide and impregnated with polyvinyl alcohol (PVA) was coupled with UV-vis spectrophotometry and used for colorimetric determination of ferrous ion (Fe²⁺) and ascorbic acid (AA). The electrospun nanofibers were characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) techniques. The main factors affecting performance of the optical sensor (PA6-Phen/PVA@glass) including Phen dosage, pH of sample solution, electrospinning time, polymer solution flowrate, electrospinning voltage, and PVA amount were investigated and the related optimum values were obtained. The analytical merits of the sensor for quantitative determination of Fe²⁺ and ascorbic acid was evaluated. The limit of detection (LOD) and limit of quantification (LOQ) for Fe²⁺ were 1 and 3 μg mL^-1, respectively. The linear dynamic range (LDR) was 3–150 μg mL^-1 with the determination coefficient (R²) of 0.991. The relative standard deviation (RSD %, n=3) for a solution of 60 μg mL^-1 was 5.4 %. For determination of AA, LOD and LOQ were obtained equal to 0.5 and 2 μg mL^-1, respectively. The linear dynamic range was in the 2–200 μg mL^-1 range with a R2 of 0.994. The RSD % at 100 μg mL^-1, n=3) was equal to 7.0 %. The sensor was applied successfully to the detection of Fe(II) and AA in real water samples and aspirin tablets.     

Evaluation of Ultrasound,Microwave, Ultrasound–Microwave,Hydrothermal and High Pressure Assisted Extraction Technologies for the Recovery of Phytochemicals and Antioxidants from Brown Macroalgae

This study aims to explore novel extraction technologies (ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), ultrasound–microwave-assisted extraction (UMAE), hydrothermal-assisted extraction (HAE) and high-pressure-assisted extraction (HPAE)) and extraction time post-treatment (0 and 24 h) for the recovery of phytochemicals and associated antioxidant properties from Fucus vesiculosus and Pelvetia canaliculata. When using fixed extraction conditions (solvent: 50% ethanol; extraction time: 10 min; algae/solvent ratio: 1/10) for all the novel technologies, UAE generated extracts with the highest phytochemical contents from both macroalgae. The highest yields of compounds extracted from F. vesiculosus using UAE were: total phenolic content (445.0 ± 4.6 mg gallic acid equivalents/g), total phlorotannin content (362.9 ± 3.7 mg phloroglucinol equivalents/g), total flavonoid content (286.3 ± 7.8 mg quercetin equivalents/g) and total tannin content (189.1 ± 4.4 mg catechin equivalents/g). In the case of the antioxidant activities, the highest DPPH activities were achieved by UAE and UMAE from both macroalgae, while no clear pattern was recorded in the case of FRAP activities. The highest DPPH scavenging activities (112.5 ± 0.7 mg trolox equivalents/g) and FRAP activities (284.8 ± 2.2 mg trolox equivalents/g) were achieved from F. vesiculosus. Following the extraction treatment, an additional storage post-extraction (24 h) did not improve the yields of phytochemicals or antioxidant properties of the extracts.     

Effect of Boiling in Water of Barley and Buckwheat Groats on the Antioxidant Properties and Dietary Fiber Composition

In recent years, there has been an ever-increasing interest in the research of polyphenols obtained from dietary sources, and their antioxidative properties. The purpose of this study was to determine the effect of boiling buckwheat and barley groats on the antioxidant properties and dietary fiber composition. Antioxidative properties were investigated using methyl linoleate model system, by assessing the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and metal chelating activity. The results were compared with butylated hydroxytoluene (BHT). Raw barley and buckwheat groats extracts showed higher DPPH scavenging ability compared to boiled barley and buckwheat groats extracts. Raw barley groats extract exhibited higher antioxidant activity than boiled groats extract in the methyl linoleate emulsion. Higher chelating ability in relation to Fe (II) ions was observed for boiled groats extracts as compared to raw groats extracts. BHT showed small antiradical activity and metal chelating activity, while showing higher antioxidative activity in emulsion system. The analysis of groats extracts using HPLC method showed the presence of rutin, catechin, quercetin, gallic, p-hydroxybenzoic, p-coumaric, o-coumaric, vanillic, sinapic, and ferulic acids. Differences in the content of dietary fiber and its fractions were observed in the examined products. The highest total dietary fiber content was detected in boiled buckwheat groats, while the lowest - in boiled barley groats. The scientific achievements of this research could help consumers to choose those cereal products available on the market, such as barley and buckwheat groats, which are a rich source of antioxidative compounds and dietary fiber.