Protective role of tea polyphenols in combination against radiation-induced haematopoietic and biochemical alterations in mice

The purpose of this study was to investigate the radioprotective effects of tea polyphenols (TPs) in various combinations against radiation‐induced damage in mice. Mice were divided into different groups: non‐irradiated control, irradiated control, amifostine (43.6 mg/kg, i.v. 30 min before irradiation; positive control) and various combinations of tea polyphenols in different doses. The radioprotective effect on the haematopoietic system, serum cytokines and endogenous antioxidant enzymes were studied. TP50, containing approximately 50% of (‐)‐epigallochatechin‐3‐gallate in addition to other catechins, showed the greatest radioprotective effect against radiation‐induced changes in haematological parameters (red blood cell count, white blood cell count and haemoglobin), and maintained the spleen and thymus indices unchanged (spleen or thymus weight/body weight × 1000). Tea polyphenols also significantly decreased radiation‐induced lipid peroxidation (malondialdehyde levels), elevated endogenous antioxidant enzymes (superoxide dismutase) and reduced the serum cytokines which were elevated in radiation‐induced toxicity. This evidence shows the potential of tea polyphenols, particularly in the combination found in TP50, as radioprotectors in mice, especially regarding recovery of the haematopoietic system, antioxidant potential activity and reduction of inflammatory cytokines. Copyright © 2011 John Wiley & Sons, Ltd.     

基于诱导细胞凋亡产生显著抗癌活性的新型ent-贝壳杉烷型化合物CPUK02

CPUK02（15-羰基甜菊苷苄酯）是由甜菊苷半合成得到的一种新型化合物。采用多种体内体外模型验证了其抗肿瘤活性,并初步探索了其抗肿瘤活性的作用机理。使用MTT法测试了该化合物的体外抗肿瘤活性,发现CPUK02对于多种肿瘤细胞株都有显著地抑制作用;此外,对于肝癌细胞该化合物的作用相较于正常肝细胞有着显著地敏感性差异,尤其在低浓度下,该化合物对癌细胞表现出较强的选择性。在多种人癌细胞小鼠异种移植瘤模型中,CPUK02表现出接近五氟尿嘧啶的抗肿瘤活性。同时使用Annexin／PI双染流式细胞术和DAPI染色的方法观察了CPUK02引起的肿瘤细胞的细胞形态学上的变化,证明了该化合物确实可以诱导细胞凋亡,该作用同时表现出明显的浓度依赖性。还使用了westernblot探索了该化合物的抗肿瘤作用的机理,发现该化合物可以作用于细胞凋亡的线粒体途径激活凋亡信号的级联转导。这些结果显示CPUK02是一种良好的抗肿瘤候选化合物,并且有可能成为一种有前途的新型药物。     

青蒿酯钠抗人肝癌(BEL-7402)与诱导凋亡

应用体内外抑瘤实验、细胞形态学观察、流式细胞仪、Westernblot实验进行检测和观察，探讨青蒿酯钠抗肿瘤作用及机制。结果表明，青蒿酯钠对人肝癌有体内、外抗肿瘤作用；诱导人肝癌细胞凋亡，可能是其抗肿瘤作用机制之一；诱导体外人肝癌细胞凋亡通过P53非依赖性途径。     

槲皮素对人骨肉瘤细胞U-2OS/MTX300增殖和凋亡的影响及其机制研究

目的:研究槲皮素(quercetin,Qu)对骨肉瘤细胞系U-2OS/MTX300增殖和凋亡的作用及其机制。方法:MTT法观察细胞增殖活性;Annexin V/PI染色检测凋亡;线粒体膜电位及细胞色素C的Western blot检测线粒体凋亡途径;持续活化Akt瞬时转染、Western blot检测Akt通路相关蛋白表达水平变化。结果:槲皮素可明显抑制耐甲氨蝶呤骨肉瘤细胞U-2OS/MTX300生长,并呈时间和剂量依赖性;Annexin V/PI可明显检测到细胞凋亡;进一步发现其作用机制是通过下调线粒体膜电位,促进细胞色素C向胞浆释放及抑制Akt磷酸化来实现。结论:槲皮素可显著抑制耐甲氨蝶呤骨肉瘤细胞系U-2OS/MTX300细胞增殖并诱导其凋亡,其机制与线粒体凋亡途径及抑制Akt活性有关。     

四藤方对Bel-7402细胞增殖和凋亡作用研究

目的:观察清热解毒中药-四藤方对肝癌细胞Bel-7402增殖和凋亡的影响。方法:不同浓度四藤方处理人肝癌细胞Bel-7402、人肝细胞HL-7702,WST-8法检测细胞增殖,流式细胞术检测细胞凋亡,Hoechst 33258染色检测细胞凋亡形态变化,Western Blot法检测半胱天冬酶-3(caspase-3)活化。结果:与对照组比较,四藤方对人肝细胞HL-7702增殖无明显影响;100～400μg.mL-1四藤方作用24 h可显著抑制肝癌Bel-7402细胞增殖,促使细胞Bel-7402凋亡,呈现细胞凋亡形态,并可活化Bel-7402细胞caspase-3。结论:四藤方可以抑制Bel-7402细胞增殖,促Bel-7402细胞凋亡,并可能与活化caspase-3相关。     

青藤碱对人肝癌细胞HepG2增殖的抑制作用

目的:研究青藤碱对人肝癌HepG2细胞增殖的影响及其机制。方法:以不同浓度青藤碱处理体外培养的A549细胞,采用MTT法检测24h、48h、72h后HepG2细胞的增殖状态;流式细胞仪测定青藤碱处理过的细胞凋亡、细胞周期分布及凋亡率,相对定量RT-PCR测定Cox-2mRNA的表达、Western blot检测细胞凋亡相关基因Cox-2的表达。结果:青藤碱能显著抑制人肝癌HepG2细胞增殖,并具有时间和剂量依赖性。青藤碱处理组细胞早期凋亡率较对照组升高,呈时间剂量依赖性。相对RT-PCR结果显示其能下调HepG2细胞Cox-2mRNA的表达。Western blot检测Cox-2蛋白表达明显抑制。结论:青藤碱在体外能有效抑制肝癌细胞增殖。     

白叶单枞和黄观音茶树芽叶中茶多酚的HPLC-DAD/MS/MS分析

 目的对两个乌龙茶的代表茶树品种白叶单枞和黄观音芽叶中的茶多酚进行定性、定量比较分析。方法茶样经体积分数50%乙腈室温超声提取后进行HPLC-DAD/MS/MS分析;采用ODS柱,流动相为乙腈和1%甲酸水溶液,进行线性梯度洗脱,扫描波长范围为200～700 nm;ESI离子化,正负离子同时检测,m/z扫描范围为150～1 500 amu,MS2碰撞能量为35 eV。结果通过与8种儿茶素对照品的比较分析,在这两个茶树品种的芽叶中鉴定出了9种儿茶素类化合物,2种嘌呤生物碱以及2种非儿茶素类茶多酚,并测定了各儿茶素类化合物的含量,回收率在97.11%～99.73%之间。结论两个茶树品种芽叶中的儿茶素类化合物组成种类基本相近,白叶单枞中酯型儿茶素的含量比黄观音高,而非酯型儿茶素的含量却比较低;(-)-epigallocatechin-3-(3″-O-methyl)gallate和(-)-epigallocatechin-3,5-digallate在我国茶树现有栽培品种中的发现为首次报道。     

儿茶素及其衍生物抗癌研究进展

动物试验研究发现,儿茶素对不同器官肿瘤的形成及发展表现出明显的抑制作用.作用机制研究显示儿茶素通过抗氧化、抑制相关酶活性及抑制信号传导等来抑制肿瘤细胞入侵、细胞增殖、细胞血管再生及转移,并诱导细胞凋亡.该文综述了饮茶与癌症预防的相关性,概述了儿茶素及其衍生物防癌、抗癌作用机制,并对儿茶素未来的研究进行了展望.     

人参皂苷Rh_2通过激活p38诱导K562细胞自噬凋亡的实验研究

为了研究人参皂苷Rh2对人白血病细胞K562的凋亡作用,并从自噬角度来探讨其机制。实验采用CCK-8方法检测人参皂苷单体Rh2对人白血病K562细胞增殖抑制作用;流式细胞术检测细胞凋亡;Hoechest染色观察细胞核染色质的形态;吖啶橙和MDC染色观察Rh2对细胞自噬的影响;Western blot和RT-PCR检测Rh2对白血病细胞自噬重要基因的表达的影响;运用自噬抑制剂(3-MA)研究自噬对细胞增殖和凋亡的影响。CCK-8显示人参皂苷Rh2在低浓度时能有效抑制白血病细胞增殖,且其抑制作用具有浓度和时间依赖性;FCM和Hoechest显示Rh2能增加细胞的凋亡和染色质呈凋亡形态改变;吖啶橙和MDC染色发现Rh2组细胞的绿色荧光增强,并出现大量酸性自噬小泡;Western blot和RT-PCR结果发现Rh2能上调Beclin-1,LC3A,LC3B,激活型Caspase-3和p-p38的表达;运用细胞自噬剂(3-MA)会削弱Rh2对K562的增殖抑制和促凋亡作用。人参皂苷Rh2可能通过激活磷酸化的p38,诱导细胞自噬途径,从而抑制K562细胞增殖和促进凋亡作用。     

Modification of gamma-radiation response in mice by green tea polyphenols

In this study we evaluated the effect of water extracts of green tea (GT) and mixtures of green tea polyphenols (GTPs), epigallocatechin gallate (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC) and epicatechin (EC) on jejunal crypt survival, endogenous spleen colony formation, and apoptosis in jejunal crypt cells of mice irradiated with gamma-ray. The radioprotective effect of green tea was compared with the effect of diethyldithiocarbamate (DDC). Jejunal crypts were protected by pretreatment of GT and ECG. Administration of GT, GTPs and EC prior to irradiation resulted in an increase in the formation of endogenous spleen colonies. The frequency of apoptosis in crypt cells was also reduced by pretreatment of GT, GTPs, EGCG, ECG and EGC. In the experiment on the effect of catechins, the effects were partly contradicted in irradiated mice. The rank order of activity was ECG > EGC > EGCG > EC on intestinal crypt survival assay, EC > EGC > ECG > EGCG on the spleen colony formation assay, EGCG > EGC > EC > ECG on inhibiting the death of cells caused by apoptosis. The results indicate that GT and GTPs may have a major radioprotective effect. Each one of the catechins was a much less effective radioprotector, suggesting that total extract or a mixture of GTPs may be more effective than individual catechins.     

3种温阳健脾汤药对非酒精性脂肪肝细胞增殖与凋亡的影响

通过油酸诱导正常肝细胞株LO2构建非酒精性脂肪肝细胞模型,探讨四君子汤、理中汤和附子理中汤对非酒精性脂肪肝细胞增殖与凋亡的影响。不同浓度的油酸诱导正常肝细胞株LO2构建非酒精性脂肪肝细胞模型,油红O染色观察非酒精性脂肪肝细胞的脂滴形成状况;全自动生化分析仪检测细胞上清液中天冬氨酸氨基转移酶(AST)、丙氨酸氨基转移酶(ALT)、总胆固醇(TC)和甘油三酯(TG)水平。分别设正常组、模型组、模型+四君子汤组、模型+理中汤组和模型+附子理中汤组,MTT检测各组细胞增殖情况;流式细胞仪检测各组细胞凋亡情况;Western blot检测各组细胞中PCNA,cleaved caspase-3,cleaved caspase-8,cleaved caspase-9,Bax和Bcl-2蛋白的表达情况。油红O染色结果显示,与低浓度诱导相比,80 mg·L~(-1)油酸诱导非酒精性脂肪肝细胞模型效果最佳,且诱导成功后细胞上清液中AST,ALT,TC和TG含量显著升高(P0.01)。MTT和流式细胞仪检测结果显示,四君子汤、理中汤和附子理中汤均能有效促进非酒精性脂肪肝细胞的增殖并抑制其凋亡(P0.01),且附子理中汤的作用效果最佳。Western blot检测结果显示,四君子汤、理中汤和附子理中汤能下调非酒精性脂肪肝细胞中cleaved caspase-3,cleaved caspase-8,cleaved caspase-9和Bax蛋白表达量,上调PCNA和Bcl-2蛋白的表达量,且附子理中汤的调节效果较其他2组药物处理更显著。该实验表明四君子汤、理中汤和附子理中汤均能有效促进非酒精性脂肪肝细胞的增殖并抑制其凋亡,且附子理中汤的作用效果最佳,其药效机制可能与3种汤药介导增殖与凋亡相关通路中关键因子的表达有关。     

雷公藤红素对白血病细胞Akt信号通路的影响及在细胞凋亡中的作用

目的 研究雷公藤红素（celastrol)对人类白?∠赴闗562细胞Akt信号通路的影响及其作用。     

茶多酚和粉防己碱联合抗肿瘤药物对鼻咽癌耐药细胞株HNE-1(200)增殖的抑制作用

目的研究天然有效成分茶多酚(TP)和粉防己碱(TET)分别联合4种常见抗肿瘤药物对鼻咽癌耐药细胞株HNE-1(200)增殖的抑制作用。方法以鼻咽癌耐药细胞株HNE-1(200)为研究对象,用MTT法测定无毒剂量的TP和TET分别联合顺铂(DDP)、5-氟尿嘧啶(5-Fu)、长春新碱(VCR)、阿霉素(ADM)对实验细胞的增殖抑制率。结果无毒剂量的TP分别与4种抗肿瘤药物联合应用后,药物对HNE-1(200)细胞的抑制率增加约200%;无毒剂量的TET分别与4种抗肿瘤药物联合应用后,药物对HNE-1(200)细胞的抑制率增加约300%。结论无毒浓度的天然药物TP、TET分别与抗肿瘤药物联合应用能提高药物对鼻咽癌耐药细胞株的增殖抑制率,降低药物的IC50。     

Excretion of Four Catechins in Tea Polyphenols in Rats

Objective To investigate excretion profiles of the four major anti-oxidant active catechins, (–) epigallo- catechin-3-gallate (EGCG), (–) epicatechin-3-gallate (ECG), (–) epigallocatechin (EGC), and epicatechin (EC) in tea polyphenols (TP) in rats in order to provide experimental data for clinical uses and development of TP as a novel drug. Methods The above four catechins in urine, bile, and feces were simultaneously determined by high performance liquid chromatography coupled with ultraviolet absorption detector (HPLC-UV) assay with a binary gradient elution. The samples were extracted by ethyl acetate prior to HPLC. The quantification was carried out by peak area internal standard method. Following iv dosing TP 100 mg/kg to rats, the samples were collected at different time intervals up to 8 h (urine and bile) and 24 h (feces). Results The urinary Ae, 0-8 h (cumulative excretion amount over 8 h) of EGCG, ECG, EGC, and EC were, on the average, 150.83, 30.75, 116.69, and 254.56 μg, corresponding to fe, 0-8 h (cumulative excretion fraction of dose over 8 h) of 1.45%, 0.84%, 7.88%, and 10.73%, respectively; the biliary Ae, 0-8 h were 12.61, 42.64, 6.61, and 1.24 μg, corresponding to the fe, 0-8 h of 0.12%, 1.16%, 0.45%, and 0.053% , respectively. For fecal excretion, only EGCG and EGC were detected with Ae, 0-24 h of 7.38 μg (fe, 0-24 h of 0.07%) and 157 μg (fe, 0-24 h of 9.99 %), respectively. The fe, total (the total fe of 3 excretory routes) were 18.32%, 10.78%, 2.00%, and 1.64% for EGC, EC, ECG, and EGCG, respectively. Conclusion EGCG and EC are mainly excreted in urine, ECG in bile, and EGC in feces by reference to their Ae and fe. The excretion of the four catechins based on fe, total is ranked in order of EGC > EC > ECG > EGCG. Only small amount of four catechins are recovered in urine, bile, and feces, indicating an extensive metabolic conversion of catechins in the rat body.     

DNA degradation by water extract of green tea in the presence of copper ions: implications for anticancer properties

In recent years a number of reports have documented the chemopreventive effect of green tea consumption on various types of cancers such as those of bladder, prostate, esophagus and stomach. This property is attributed to the presence in green tea of polyphenols known as catechins. These include epigallocatechin-3-gallate, epigallocatechin and epicatechin. In addition to their antioxidant properties plant derived polyphenolics are also capable of oxidative DNA damage particularly in the presence of transition metal ions. We have recently proposed a mechanism for cytotoxic action of plant-derived polyphenols against cancer cells that involves mobilization of endogenous copper and consequent prooxidant action. In partial support of the idea, in the present paper we show that water extract of green tea is considerably more efficient than black tea extract in DNA cleavage in the presence of copper ions. Green tea extract also shows a higher rate of Cu(II) reduction and consequent hydroxyl radical formation. Cu(II) reduction is presumably accompanied by the formation of 'oxidized species' of tea polyphenols, which in turn also appear to catalyze the reduction of Cu(II) leading to redox cycling of copper ions. The results are discussed in relation to the structural differences between polyphenols of green and black tea.     

重楼皂苷D对人胰腺癌细胞增殖和凋亡的影响

重楼皂苷D(polyphyllin D)是重楼中的一种甾体皂苷单体,具有抗菌、镇痛、镇静、抗肿瘤等多种药理作用,但在胰腺癌中少有报道。该研究通过检测凋亡相关指标,探讨polyphyllin D对人胰腺癌Panc-1细胞增殖和凋亡的影响及相关作用机制。采用CCK-8法检测不同浓度的(0,1,2,3,4,5μg·μL-1)polyphyllin D分别处理胰腺癌Panc-1细胞24,48,72 h后,观察对细胞增殖的影响。采用流式细胞术对细胞周期、细胞线粒体膜电位(mitochondrial membrane protential,MMP)进行检测,Annexin-V-FITC/PI双染法检测细胞凋亡情况,Western blot法检测细胞色素C (cytochrome C,Cyto C),Bax,Bcl-2,cleaved caspase-3,cleaved caspase-9的蛋白表达情况。结果表明,与对照组相比,polyphyllin D能够时间和浓度依赖性地抑制Panc-1细胞的增殖活性。流式细胞术检测显示polyphyllin D能浓度依赖性使细胞阻滞于S期和G2/M期,MMP明显降低,细胞凋亡率随polyphyllin D作用浓度增加而增加。Western blot结果显示,polyphyllin D能浓度依赖性地上调Bax,Cyto C,cleaved caspase-3和cleaved caspase-9的蛋白表达水平,下调Bcl-2的蛋白表达水平。以上研究结果提示,polyphyllin D能抑制胰腺癌Panc-1细胞的增殖,其机制可能与阻滞细胞的生长周期以及通过线粒体途径诱导细胞的凋亡相关。     

The effect of a catechin-rich extract of Cocos nucifera on lymphocytes proliferation

Catechins are polyphenols with antioxidant activity. The fruit Cocos nucifera (Palmae) has a fi ber husk rich in catechins and the local population of northeast Brazil uses it as a medicine against various diseases. An anti-bacterial and anti-viral activity has been already observed using this substance. Plant extracts, from other sources, rich in catechins are inhibitory to tumour cells, suppressing their proliferation. The aim of the present work was to verify if catechins isolated from Cocos nucifera were capable of inhibiting cell proliferation. An extract obtained from Cocos nucifera was purified through adsorption chromatography using the resin XAD-2. The purified material was used in cultures of an erythroleukaemia cell line (K562) and on normal human peripheral blood lymphocytes. Cell viability was assessed using MTT. Cellular proliferation was measured by [(3)H]-thymidine incorporation and cell cycle analysis in a fl ow cytometer. A dose-dependent inhibitory effect was observed on tumour cells and on lymphocytes activated by phytohemaglutinin (PHA) or phorbol ester. For PHA this effect was irreversible being already established on the fi rst four hours of culture.     

马兜铃酸诱导TM3小鼠睾丸间质细胞凋亡机制

目的:探讨马兜铃酸(AAs)对TM3细胞凋亡的作用及分子机制。方法:用2.5、10、25、100、400、1000 μmol/L浓度的马兜铃酸分别对TM3细胞作用24、48、72 h后,CCK-8法测定细胞活力; 25、100、400 μmol/L的马兜铃酸对TM3细胞作用48 h后,TUNEL检测细胞凋亡率,实时荧光定量法检测Caspase通路相关基因Caspase-3、Caspase-9和Bax mRNA相对表达情况,并通过Western blot法检测凋亡相关蛋白Caspase-3、Caspase-9和Bax蛋白表达水平变化。结果:不同浓度的马兜铃酸对小鼠睾丸间质细胞的活力有一定的抑制作用; 用25、100、400 μmol/L浓度的马兜铃酸处理TM3细胞48 h后,通过TUNEL染色发现,不同浓度的马兜铃酸能够促进细胞的凋亡,Caspase-3、Caspase-9、Bax mRNA和蛋白表达水平升高。结论:马兜铃酸通过Caspase途径促进TM3细胞的凋亡来影响生殖细胞的发育。     

茶多酚对大鼠血管平滑肌细胞增殖的影响

目的　探讨茶多酚对离体大鼠胸主动脉血管平滑肌细胞增殖的影响。方法　体外培养大鼠主动脉血管平滑肌细胞 ,应用不同剂量的茶多酚作用 2 4 h后 ,采用 MTS/ PES法确定血管平滑肌细胞的增殖状态。应用流式细胞术测定细胞周期。结果　与对照组相比 ,茶多酚对血管平滑肌细胞增殖具有明显的抑制作用 (P<0 .0 0 1)。流式细胞术检测结果表明 ,茶多酚可以使血管平滑肌细胞大部分处于 G0 / G1 期 ,与对照组相比有明显差异 (P<0 .0 5 ) ,并且可以诱导其凋亡。结论　茶多酚可明显抑制离体大鼠血管平滑肌细胞的增殖。     

普洱茶药理作用研究进展

随着社会发展以及人们保健意识的增强,普洱茶逐渐受到关注。普洱茶属后发酵茶,富含黄酮类、儿茶素类、芬酸类、黄烷醇聚合物、嘌呤类生物碱、可水解鞣质等活性成分,具有降脂、降糖、抗氧化、抗肿瘤、抗菌、消炎、抗病毒等多种药理活性。该文主要就其药理活性进行综述,希望为普洱茶的进一步研究提供依据。