红茶及其多酚类茶黄素茶玉红精的抗诱变活性

作者通过检测染色体畸变(CA)和姐妹染色单体交换(SCE),研究了红茶及其所含多酚类茶黄素(TF)和茶玉红精(TR)对环磷酰胺(CP)和二甲基苯并蒽(DMBA)诱导的基因损伤的抑制作用。1)在 CA 实验中,红茶水提取物分为     

红茶中多酚类物质的抗氧化机制及其构效关系

绿茶中主要多酚类物质为儿茶素。儿茶素抗氧化作用与机制已经较明确。茶黄素作为红茶中主要多酚类物质,是衡量红茶品质的重要指标,也是红茶中发挥生物学作用的主要物质。根据目前关于红茶中多酚类物质的研究报道,分析了茶黄素结构对抗氧化活性的影响,并阐明其发挥抗氧化作用的机制。     

茶黄素-3,3′-双没食子酸酯对人骨肉瘤细胞的抑制作用及转录组学分析

目的 采用转录组学等技术探讨茶黄素-3,3′-双没食子酸酯(theaflavin-3,3′-digallate,TF3)对人骨肉瘤(HOS)细胞的抑制作用及其潜在机制。方法 分别使用不同浓度的TF3和体积分数0.05%的二甲基亚砜(dimethyl sulfoxide, DMSO)处理HOS细胞后,采用CCK-8(cell counting kit-8)法、结晶紫染色、集落形成实验和流式细胞术来检测TF3对HOS细胞增殖的影响; Hoechst33258染色实验及流式细胞术检测TF3对HOS细胞凋亡的影响;Western blot检测HOS细胞增殖和凋亡相关蛋白的水平;采用转录组测序检测TF3处理组和对照组HOS细胞的差异基因表达情况,并使用生物信息学分析潜在分子机制。根据转录组测序结果,采用实时荧光定量PCR法检测各组细胞中分泌粒蛋白Ⅱ(SCG2),蛋白酪氨酸激酶受体B1(EPHB1)和紧密连接蛋白7(CLDN7) mRNA 的表达。结果 与对照组相比,TF3处理组中HOS细胞的增殖能力明显受到抑制(P＜0.05),同时细胞凋亡率显著增高(P＜0.05),呈浓度依赖性;增殖相关蛋白增殖细胞核抗原(PCNA)和细胞增殖抗原(Ki67)及抗凋亡蛋白B细胞淋巴瘤/白血病-2(Bcl-2)表达量降低,凋亡相关蛋白半胱氨酸天冬氨酸蛋白酶3(caspase-3)的水平下降,凋亡标志蛋白B细胞淋巴瘤/白血病-2相关X蛋白(Bax)、活化的半胱氨酸天冬氨酸蛋白酶3(cleaved caspase-3)和细胞色素C的表达量升高(P＜0.01);HOS细胞转录组测序结果显示,TF3处理组与对照组相比有809个差异表达基因(P-adjust＜0.05),其中596个上调,213个下调;基因本体论 (gene ontology,GO)主要富集于DNA复制的正调控、膜及蛋白结合等功能方面,京都基因与基因组百科全书(Kyoto Encyclopedia of Genes and Genomes,KEGG)主要富集于缺氧诱导因子1信号通路、癌症通路及肿瘤坏死因子信号通路等包括凋亡在内与肿瘤相关的信号通路。与对照组相比,TF3处理组的SCG2, EPHB1, 和CLDN7 mRNA 表达水平下调(P＜0.05)。结论 TF3可能通过多靶点调控多种信号通路的活性,从而抑制HOS细胞增殖并促进其凋亡。     

大孔吸附树脂纯化红茶中茶黄素的研究

目的研究大孔吸附树脂纯化红茶中茶黄素的工艺。方法通过静态吸附实验比较不同树脂对茶黄素的吸附和解吸能力,考察HPD-300树脂对茶黄素的吸附性质,比较不同溶液的动态解吸效果。结果 HPD-300树脂具有较高的吸附和解吸能力,在25℃和45℃下HPD-300树脂对茶黄素的吸附等温线符合Freundlich方程。经过动态吸附解吸后茶黄素由18.4%提高到67.2%,回收率达到73.7%。结论 HPD-300树脂对茶黄素具有良好的分离能力,为茶黄素的大规模制备提供了科学参考。     

茶黄素复合物中单体对照品的制备研究

目的 研究茶黄素复合物和单体的对照品分离制备.方法 AB-8树脂吸附茶黄素,乙醇梯度洗脱得茶黄素复合物,进一步用半制备液相色谱分离茶黄素单体.结果 AB-8大孔树脂进行吸附,20%、30%、40%、50%、60%乙醇溶液梯度洗脱.洗脱速度为2 BV/h,制得质量分数80%的茶黄素复合物.以制备色谱进一步分离获得质量分数90%以上茶黄素-3-没食子酸酯、茶黄素-3'-没食子酸酯和茶黄素-3,3'-双没食子酸酯,以及质量分数大于70%的茶黄素的单体.结论 大孔吸附树脂和制备色谱结合可以从茶黄素复合物中获得比较理想的单体对照品.     

茶黄素衍生物抗甲型流感病毒的作用研究

目的 研究茶黄素衍生物的混合物(含茶黄素、茶黄素-3-没食子酸酯、茶黄素-3'-没食子酸酯和茶黄素-3,3’-双没食子酸酯,简称茶黄素衍生物)抗甲型流感病毒的作用及其机制.方法 采用H5N1假病毒检测体系,观察茶黄素衍生物对A/Thailand/Kan353/2004 H5N1毒株假病毒的抑制作用;采用血凝抑制实验和神经氨酸酶抑制实验进一步分析茶黄素衍生物抗甲型流感病毒的作用机制;采用H1N1 FM 1病毒检测体系,观察茶黄素衍生物对甲型流感病毒FM1的抑制作用;采用MTT法评价茶黄素衍生物对MDCK细胞的毒性.结果 茶黄素衍生物能明显的抑制H5N1假病毒的感染力,IC50为(151.88±18.95)μg/nL;对血凝素HA1亚基无抑制作用;对神经氨酸酶具有抑制作用,IC50为(129.09±1.33)μg/mL;能明显抑制甲型流感病毒FM 1株.此外,茶黄素衍生物对MDCK细胞的毒性较小,CC50为(879.89±4.54) μg/mL.结论 茶黄素衍生物可能通过与血凝素HA2亚基结合而抑制禽流感病毒的感染,同时能够在一定程度上抑制病毒的神经氨酸酶活性,提示茶黄素衍生物是通过多靶点发挥抗H5N1亚型禽流感病毒的作用.     

三七和茶黄素对成人Ⅳ期股骨头坏死表面软骨生长的影响

目的观察三七和茶黄素对成人Ⅳ期股骨头坏死表面软骨生长情况的影响。方法收集在全髋置换手术中获得的成人股骨头表面软骨标本,将标本打碎后分离培养软骨细胞。实验分为三七组、茶黄素组、三七+茶黄素组、对照组,对照组细胞培养不添加任何药物,三七组添加30μg/mL三七粉培养,茶黄素组添加20μg/mL茶黄素培养,三七+茶黄素组添加10μg/mL三七粉+10μg/mL茶黄素培养。分别于培养第3天、第7天、第10天在显微镜下观察软骨细胞形态与生长情况,并采用噻唑蓝(MTT)法检测各组培养48 h后软骨细胞增殖情况。结果培养基中可见接种细胞为小圆形细胞,并伸长形成突起状,早期多呈多角形,符合软骨细胞形态。各药物组培养第3天、第7天、第10天显微镜下的细胞形态与对照组相比没有明显差异。软骨细胞增殖活力OD值三七组为0.34±0.02,茶黄素组为0.36±0.03,三七+茶黄素组为0.37±0.01,对照组为0.36±0.03,各组间相互比较差异均无统计学意义(P均0.05)。结论单独应用三七和茶黄素,或者两者混合物都不能改善成人股骨头表面软骨细胞的生长活性。     

茶黄素降低缺血再灌注损伤大鼠心室肌细胞内游离钙浓度的研究

目的研究茶黄素对大鼠心室肌细胞内游离钙浓度([Ca2+]i)的影响并探讨其可能机制。方法在正常台氏液和模拟缺血液中,用激光共聚焦显微镜探测[Ca2+]i,结果用相对荧光强度表示。结果茶黄素(20μmol/L)对正常台氏液中心室肌细胞内[Ca2+]i有影响,但可降低模拟缺血液中心室肌细胞[Ca2+]i的增加。应用钠钙交换体抑制剂NiCl2(100μmol/L)可模拟茶黄素(20μmol/L)在模拟缺血液中的作用。预先应用肌浆网钙泵抑制剂Thapsigar-gin(0.5μmol/L)可大部分取消茶黄素(20μmol/L)在模拟缺血液中的作用。结论茶黄素可通过抑制钠钙交换体转运和增强肌浆网钙泵活动,抑制缺血再灌注损伤中细胞[Ca2+]i的增加。     

木瓜果实中具有体外组织因子抑制活性的新三萜类化合物

组织因子(组织促凝血酶原激酶,TF)作为辅因子,激活内、外源性途径而促进凝血。为了从木瓜(Chaenomelessinensis)果实中分离TF抑制剂,从中得到4个化合物。干燥的木瓜果实(20kg)用甲醇提取3次。甲醇提取物(4.6kg)依次在正己烷(140g)、乙酸乙酯(350g)、正丁醇(973g)和水(2960g)中分配。乙酸乙酯提取部分于50%甲醇中分为50%甲醇可溶部分(79g)和不溶部分(223g)。50%甲醇可溶部分经反复SephadexLH-20柱层析,用甲醇-水(1∶1)洗脱,得到活性部分A(19g)和无活性部分B(38g)。活性部分A经硅胶柱层析,用氯仿-甲醇-水(5∶1∶0.1,3∶1∶0.1)洗脱,得到…     

茶黄素对大鼠缺血性脑损伤的预防作用

目的:观察茶黄素对大鼠缺血性脑损伤的预防作用。方法:64只健康成年SD大鼠随机分为4组:假手术组、模型组与茶黄素低、高剂量组。茶黄素低、高剂量组分别ig 20,40 mg·kg-1茶黄素,假手术组和模型组分别ig等体积生理盐水。连续给药7 d后,采用大脑中动脉线栓法(MCAO)复制大鼠实验性脑缺血模型。缺血24 h后,观察大鼠行为并用Longa法进行神经行为学评分。从每组中随机取6只计算大鼠的脑组织含水量,其余10只测定脑组织超氧化物歧化酶(SOD),丙二醛(MDA),一氧化氮(NO)水平。结果:与假手术组相比,模型组大鼠出现明显的行为学障碍,脑组织含水量,MDA,NO含量升高,SOD活性降低。与模型组相比,茶黄素低、高剂量组大鼠行为学评分显著提高,脑组织含水量和MDA含量显著降低,SOD活性显著提高,高剂量组NO含量显著降低。结论:茶黄素对大鼠缺血性脑损伤有一定的预防作用。     

Effects of black tea extract on carbon tetrachloride-induced lipid peroxidation in liver, kidneys, and testes of rats

Previous studies have shown that green tea and black tea have antioxidant effects and chemopreventive activity against chronic disease including some forms of cancer. We have, therefore, examined the effects of an aqueous extract of black tea against carbon tetrachloride-induced lipid peroxidation as determined by the formation of thiobarbituric acid reactive substances in liver, kidneys and testes of rats. A 0.7% black tea extract was used which contained 2 mg of black tea extract solids per mL. Black tea was administered as drinking water for 3, 6, 9 and 12 months before and during carbon tetrachloride (CCl(4)) treatment in female and male rats. Rats were treated with a single oral dose of CCl(4) 1.0 mL/kg. All rats were killed 24 h after CCl(4) treatment. All animals were dosed with CCl(4) at the end of the 3, 6, 9, and 12 month of treatment. Black tea treatment for 75 days produced a decrease in CCl(4)-induced hepatic lipid peroxidation but significant decreases in thiobarbituric acid reactive substances occurred 3 months after treatment in both female and male rats. In liver and kidneys, black tea alone increased lipid peroxidation by 30%-50% in female and male rats. However, black tea decreased CCl(4)-induced lipid peroxidation in liver of female and male rats by approximately 49% and 37%, respectively. Black tea decreased CCl(4)-induced lipid peroxidation in testes by approximately 37% at a dose of 1.0 mL CCl(4)/kg. These results suggest that the protective effects of black tea against CCl(4)-induced lipid peroxidation in liver, kidneys and testes is due at least partly to its antioxidant properties, scavenging CCl(4)-associated free radicals.     

Inhibition of tumour growth and inflammation by consumption of tea

The antitumour effect of tea was evaluated in the 3-methylcholanthrene (3-MC) induced solid tumour model in mice. Both black and green tea inhibited tumour growth and prevented metastasis. Histopathological study showed that tea treatment was able to reduce malignancy. Superoxide dismutase (SOD), a free radical scavenger, was found to be significantly increased in the serum of mice administered tea. Moreover, tea extracts were able to reduce the level of thiobarbituric acid reactive substance (TBARS) in the sera of mice. Tea extracts (both black and green) also showed antiinflammatory activity in the carrageenan-induced paw oedema model in the rat.     

Anti-oxidative,anti-inflammatory and hepato-protective effects of Ligustrum robustum

Aqueous extract of processed leaves of Ligustrum robustum could dose-dependently scavenge superoxide radicals, inhibit lipid peroxidation, and prevent AAPH-induced hemolysis of red blood cells. In comparison with green tea, oolong tea and black tea, processed leaves of L. robustum exhibited comparable antioxidant potency in scavenging superoxide radicals and in preventing red blood cell hemolysis. By activity-guided fractionation, a glycoside-rich fraction named fraction B2 was separated and demonstrated to possess strong antioxidant effect. It was evaluated for its anti-inflammatory and hepato-protective activities. A single oral dose of fraction B2 at 0.5 g/kg could provide 51.5% inhibition on the vascular permeability change induced by intraperitoneal injection of acetic acid, but it could not inhibit croton oil-induced ear edema. On the other hand, fraction B2 exhibited moderate hepato-protective effect. Intragastric application of fraction B2 at 1.25, 2.5 or 5 g/kg 6 h after carbon tetrachloride administration could reduce the elevations of serum levels of aminotransferases (AST and ALT). Also, liver integrity was preserved, as liver sections from rats post-treated with fraction B2 showed a milder degree of fatty accumulation and necrosis. These results offer partial support to the traditional uses of the leaves of L. robustum as Ku-Ding-Cha.     

Effect of nutrient mixture and black grapes on the pharmacokinetics of orally administered (-)epigallocatechin-3-gallate from green tea extract: a human study

(-)Epigallocatechin-3-gallate (EGCG), a green tea component, has been attributed with anticarcinogenic and antioxidant activities. The extent and rate of absorption of EGCG by the small intestine depends on various factors such as molecular size, lipophilicity, solubility, pKa, gastric and intestinal transit time, lumen pH, membrane permeability and first pass metabolism. The bioavailability of EGCG can be increased by decreasing the presystemic elimination by stabilizing EGCG in the lumen, helping its transfer across the intestinal apical membrane and its accumulation and thus its availability by inhibiting phase I and II enzymes and phase III transporters. In a crossover study, five human volunteers were given a single oral dose of GTE (A), nutrient mixture (NM) containing GTE (B) and formulation B along with black grapes 250 g (C). Blood samples were drawn at 0, 2, 4, 6 and 8 h. The pharmacokinetic parameters were analysed by WinNonLin (Vs 5.0.1.) using a non-compartmental approach. Supplementation with nutrient mixture normally prescribed to cancer patients containing ascorbic acid, selenium, N-acetyl cysteine and other nutrients (formulation B) resulted in an increase of the systemic availability of EGCG by 14% and formulation C further increased it by 13%, thus leading to a total increase of 27%.     

Investigation of in vitro antioxidant activity of dihydromyricetin and flavonoids rich extract from vine tea(Ampelopsis grossedentata)

Background:Vine tea from fermented Ampelopsis grossedentata leaves has been used as a herbal tea and folk medicine in the southern region of China for hundreds of years.The aim of this investigation was to analyze the total flavonoids found in vine tea,including three bioactive flavonoids,and the total phenolic contents in the aqueous methanol extracts of 10 vine tea samples.In addition,this study also aimed to examine the antioxidant activity of dihydromyricetin and vine tea’s flavonoid-rich extract.Methods:The total flavonoids and total phenolic content assay of extracts from vine tea were performed by ultraviolet-visible spectroscopy and epoch microplate spectrophotometer,respectively.Three bioactive flavonoids were quantified simultaneously using high performance liquid chromatography.The antioxidant activity of dihydromyricetin and vine tea’s flavonoid-rich extract was evaluated in vitro using six different methods.Results:Vine tea contained a large number of flavonoids,with dihydromyricetin as its main constituent.The flavonoid-rich extract exhibited a significant scavenging effect on superoxide anion radicals,and on 3-ethylbenzthiazoline-6-sulphonic acid and 1,1-diphenyl-2-picrylhydrazyl radicals.It also possessed definite activity in lipid peroxidation inhibition,ferric reduction,and the moderation of Fe2+ion chelation ability.There was a significant negative correlation between dihydromyricetin content and antioxidant activity in the vine tea samples,including superoxide anion radical scavenging activity(P=−0.754,P<0.05),lipid peroxidation inhibition activity(P=−0.759,P<0.05),ferric-reducing antioxidant power(P=−0.843,P<0.01),respectively.Dihydromyricetin played a dominant role in the antioxidant activities of the flavonoid-rich extract.Conclusion:Vine tea’s flavonoid-rich extract could be used as a new antioxidant source to safeguard against oxidative stress.     

Correlation between the in vitro antioxidant activity and polyphenol content of aqueous extracts from Bulgarian herbs

The water phase antioxidant activity of extracts from 23 Bulgarian medicinal plants was studied in relation to their polyphenol content in comparison with mate, black tea, honeybush and rooibos foreign species. Antioxidant activity was measured by the ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)) cation radical decolorization assay, and the total polyphenol content was assayed according to the Folin-Ciocalteu method. Five Bulgarian plant extracts exhibited higher antioxidant activity than that of mate, which is 21.7% of all Bulgarian herbs included in this study. These were Alchemilla vulgaris L. (4.79 +/- 0.14 mm), Sambucus ebulus L. (4.03 +/- 0.07 mm), Mentha spicata L. (3.90 +/- 0.03 mm), Fragaria vesca L. (3.74 +/- 0.06 mm), Crataegus monogyna Jacq. (3.63 +/- 0.05 mm). Another eight Bulgarian medicinal plant extracts exhibited an intermediate antioxidant activity - lower than that of mate and higher than that of honeybush, which makes 34.8% of all Bulgarian herbs included in the study. More than half of the herbal extracts included in the present study exhibited antioxidant activity higher than or comparable to the reference foreign plants. A positive correlation (r = 0.92) between antioxidant activity and polyphenol content was found, suggesting that the antioxidant capacity of the aqueous plant extracts is due to a great extent to their polyphenols.     

Tea and Citrus maxima complex induces apoptosis of human liver cancer cells via PI3K/AKT/mTOR pathway in vitro

Objective In this study, black tea and Citrus maxima (BT-CM), yellow tea and C. maxima (YT-CM), green tea and C. maxima (GT-CM) as subjects, the active ingredient content and antioxidant activity of three tea and C. maxima (T-CM) were analyzed. The effects of three T-CMs on apoptosis of liver cells in vitro and its mechanism were further explored. Methods National standard method and HPLC were used for active ingredient analysis. MTT, cell flow cytometry and Western blot were used to analyze the effects of three T-CMs on cell proliferation, apoptosis, and its underlying molecular mechanism. Results The content of tea polyphenols, free amino acids, ratio of polyphenols and amino acids, ester catechins, non-ester catechins and caffeine in YT-CM and GT-CM was significantly higher than that of BT-CM. The in vitro antioxidant capacity of YT-CM and GT-CM was also significantly stronger than that of BT-CM. Three T-CMs had the effects of inhibiting proliferation, arresting cell cycle and inducing apoptosis in HepG2 and Bel7402 cells, especially YT-CM and GT-CM. Western blot analysis showed three T-CMs activated PI3K/AKT/mTOR signaling pathway and regulated the expression levels of apoptosis-related proteins Bax, Bcl-2 and Caspase-3/9. YT-CM and GT-CM had better ability to change the signal pathway than BT-CM. Conclusion In short, T-CMs, which combined different degrees of fermentation tea with C. maxima, were rich in nutrients and biologically active substances. T-CMs, especially YT-CM and GT-CM, are healthy drinks that help to prevent and treat liver cancer.     

Polyphenolic constituents of Actaea racemosa

A new lignan, actaealactone (1), and a new phenylpropanoid ester derivative, cimicifugic acid G (2), together with 15 known polyphenols, protocatechuic acid, protocatechualdehyde, p-coumaric acid, caffeic acid, methyl caffeate, ferulic acid, ferulate-1-methyl ester, isoferulic acid, 1-isoferuloyl-beta-d-glucopyranoside, fukinolic acid, and cimicifugic acids A, B, and D-F, were isolated from an extract of the rhizomes and roots of black cohosh (Actaea racemosa). The structures of the new compounds were determined on the basis of NMR spectroscopic analysis. Compounds 1 and 2 displayed antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical assay with IC(50) values of 26 and 37 microM, respectively. Other antioxidants identified from A. racemosa include cimicifugic acid A (3), cimicifugic acid B (4), and fukinolic acid (5). Compounds 1 and 2 also exhibited a small stimulating effect on the growth of MCF-7 breast cancer cell proliferation 1.24-fold (14 microM) and 1.14-fold (10 microM), respectively, compared to untreated cells.     

Bioactive brominated metabolites from the red sea sponge Suberea mollis

Reinvestigation of the Red Sea sponge Suberea mollis afforded two new bromotyrosine-derived alkaloids, subereamollines A (1) and B (2), two new brominated phenolic compounds, subereaphenols B (7) and C (9), and the known compounds aerothionin (3), homoaerothionin (4), 11,19-dideoxyfistularin-3 (5), aeroplysinin-1 (6), and aeroplysinin-2 (8). The structure determination of the isolated compounds was assigned using one- and two-dimensional NMR spectra and HRFABMS data. The antimicrobial and antioxidant activities of the isolated compounds have been evaluated. Aeroplysinin-1 displayed significant antimicrobial activity against S. aureus, P. aerugenosa, and K. pneumoniae. The isolated compounds were examined for their antioxidant activity using a 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) solution-based chemical assay. Among the tested compounds, only subereaphenols B and C displayed a significant effect.     

Benzophenones from Hypericum carinatum

Two new benzophenones were isolated from the leaves of Hypericum carinatum. Their structures were established on the basis of 2D NMR spectroscopic analyses and mass spectrometry as cariphenone A (6-benzoyl-5,7-dihydroxy-2,2,8-trimethyl-2H-chromene) (1) and cariphenone B (8-benzoyl-5,7-dihydroxy-2,2,6-trimethyl-2H-chromene) (2). Five known compounds, the phloroglucinol derivative uliginosin B (3), 1-eicosanol, sitosterol, stigmasterol, and campesterol, were also characterized. Compounds 1-3 were evaluated for their total antioxidant capacity through a total radical-trapping parameter assay. Only compound 1 showed moderate antioxidant activity, exhibiting inhibition of chemiluminescence similar to that of quercetin at the same concentration.