金钱龟酶解多肽的分离、纯化及抗肿瘤活性研究

本研究以金钱龟肉糜为原料,通过可控的酶解技术制备抗肿瘤活性肽,研究中分别用胰蛋白酶、碱性蛋白酶、木瓜蛋白酶和复合蛋白酶protamex对金钱龟肉糜进行酶解并结合超滤初步分离得到了12种酶解产物,MTT实验表明其中胰蛋白酶酶解所得分子量小于3000 u的多肽E其抗肿瘤效果最强,当浓度为1 mg/m L时,对人肝癌细胞(Hep G-2)和人乳腺癌细胞(MCF-7)的抑制率分别为92.95%和67.08%。将E利用Sephadex G-15进一步纯化,经MTT实验筛选得到两组活性较强的多肽组份E1和E2,对Hep G-2的抗增殖效果来看E1(IC50为77.29μg/m L)强于阳性对照5-氟尿嘧啶(IC50为136.27μg/m L),对于MCF-7的抗增殖效果来看E2(IC50为214.17μg/m L)同样要强于阳性对照5-氟尿嘧啶(IC50为245.82μg/m L)。本研究中,抗肿瘤活性肽首次从金钱龟中分离得出,对于以金钱龟为原料的抗肿瘤药物和保健品的开发具有重要指导意义。     

茜草精油抗氧化及抗癌活性研究

以水蒸气蒸馏法提取茜草精油,以天然和合成的抗氧化剂为对照,用4种不同的抗氧化体系(ABTS+·,过氧化氢,FRAP和还原力)检测法估价精油的抗氧化活性。精油呈现出在不同体系中剂量依赖式不同程度的功效。抗癌活性的检测使用人体乳腺癌MCF-7和宫颈癌Hela细胞株,结果发现精油对于2种肿瘤细胞均有较强活性,IC_(50)分别为(1.052±0.396)mg/m L和(0.275±0.026)mg/m L,MTT和LDH检测均表明精油抗癌活性对Hela细胞明显更强;1 g精油中总酚含量为0.220 mg/m L没食子酸当量。研究结果表明茜草精油可作为重要的天然抗氧化剂。     

普洱茶水提物抗肿瘤的实验研究

应用甲基噻唑基四唑(MTT)比色法检测普洱茶水提物对6种不同肿瘤细胞株生长抑制作用以及流式细胞仪分析普洱茶水提物对Hela细胞凋亡的影响;采用裸鼠移植瘤模型,观察普洱茶水提物对宫颈癌的治疗作用。体外细胞毒活性检测显示,普洱茶水提物对人肝癌BEL-7402、胃癌MGC-823、乳腺癌MCF-7、子宫颈癌He La及结肠癌HT-29均有抗肿瘤作用,其中普洱茶水提物200μg/m L浓度下肿瘤细胞生长抑制率可达79%以上。普洱茶水提物能诱导Hela细胞发生凋亡,当浓度为100μg/m L,细胞凋亡率为(50.92±5.38)%。荷瘤鼠实验结果显示:连续给药28 d,普洱茶水提物1.0 g/kg剂量组、0.5 g/kg剂量组对人宫颈癌Hela移植瘤抑制率分别为40.3%、22.4%。普洱茶水提物在体外和体内均具有一定的抗肿瘤作用。     

藏红花水提取物抑制人卵巢癌细胞HO-8910的增殖作用

本文研究了藏红花水提取物抑制HO-8910人卵巢癌细胞的增殖作用。将实验分为细胞组、藏红花水提物低剂量组（0.4 mg/L）、中剂量组（0.8 mg/L）、高剂量组（1.0 mg/L）,HO-8910细胞培养成功后,分别用不同浓度的藏红花水提物进行处理,检测卵巢癌细胞的增殖能力及细胞外调节蛋白激酶（ERK）、Bcl-2、Bax蛋白的含量。结果表明,在实验浓度范围内,随着藏红花水提物浓度的提高,卵巢癌细胞的增长率明显受到抑制,其中,高剂量组作用时,24 h、48 h、72 h的增殖率分别为14.13%、12.15%、和11.16%,显著低于其他各实验组（p<0.05）;另外,高剂量组藏红花水提物作用后,其对卵巢癌细胞的凋亡率以及对癌细胞侵袭能力的抑制率分别为20.11%和64.24%,其ERK、Bcl-2、Bax蛋白表达量分别为0.61、0.48和0.95,与其他实验组均具有显著性差异（p<0.05）。说明藏红花水提取物能够明显抑制卵巢癌细胞活性,降低卵巢癌细胞增殖能力及侵袭能力,其作用机制可能与ERK信号通路有关。     

柘树果实的抗乳腺癌活性部分的提取、分离及结构鉴定

为了得到柘树果实中具有抗乳腺癌活性的化合物,以人乳腺癌细胞MDA-MB-231和人乳腺癌细胞MCF-7为细胞模型,通过噻唑蓝（methyl thiazolyl tetrazolium,MTT）比色法评价柘树果实石油醚浸膏、乙酸乙酯浸膏、以及正丁醇浸膏粗提取物部位的功能,实验发现乙酸乙酯部位具有明显的抑制乳腺癌细胞的活性,其对乳腺癌细胞MDA-MB-231和MCF-7的IC50分别为：75.4 μg/mL和66.8 μg/mL。采用Sephadex LH-20柱层析和硅胶柱层析对乙酸乙酯部位进行分离,采用单晶X衍射对得到的化合物进行结构鉴定,得到2 种晶体主成分,分别为4’-O-甲基-吡喃异黄酮、吡喃异黄酮。采用MTT方法对获得的2 种单体进行抗乳腺癌活性研究,发现吡喃异黄酮对乳腺癌细胞MCF-7的生长抑制率达到56.7%。结果表明,柘树果实乙酸乙酯部位含有抗乳腺癌成分,且分离得到2 种类异黄酮化合物,其中吡喃异黄酮体现出一定的抗乳腺癌活性。     

番茄红素对体外肿瘤细胞抑制作用的研究

以纯度≥99%的番茄红素晶体为研究对象,通过体外培养入宫颈癌细胞（Hela）、人黑色素瘤细胞（LiBr）进行抑制肿瘤能力试验。MTT法、细胞生长曲线测定、平板克隆形成试验结果显示,番茄红素对体外培养Hela、LiBr细胞有显著的抑制作用（p＜0．01）,培养96h后半数抑制浓度(IC50)分别为10．2μmol/L和10．8μmol/L．存在显著的剂量-效应、时间-效应关系。培养10d后Hela各处理孔未见细胞集落形成,LiBr各处理孔仅有少量细胞集落形成。培养48h后,两种细胞培养上清液中乳酸脱氢酶（LDH）水平显著升高,番茄红素使Hela、LiBr细胞膜损伤,提示番茄红素对Hela、LiBr细胞的抑制与直接杀伤有关。     

龙须菜藻红蛋白对Hela细胞增殖抑制及其机制的研究

目的:探讨龙须菜藻红蛋白(PE)对人宫颈癌细胞Hela体外的抑制作用及其作用机制。方法:采用MTT法检测不同浓度的藻红蛋白对Hela细胞增殖抑制效果。流式细胞仪和Annexin V-FITC/PI双荧光染色法观察藻红蛋白对Hela细胞周期及细胞凋亡的影响。结果:PE可显著抑制Hela细胞的生长,并呈剂量-效应关系(p<0.01,r=0.84),剂量为20μg/ml,作用48h,其抑制率达70.88%,其48h的IC50值为4.12μg/ml。PE可阻滞Hela细胞从G2/M期进入S期,诱导细胞凋亡。结论:PE对Hela细胞有较强的抑制作用,其作用机制部分与诱导Hela细胞调亡有关。     

酸浆五种部位醇提物的活性比较研究

目的:探讨酸浆根、茎、叶、宿萼和浆果醇提物的抑菌、抗氧化、抗肿瘤和抑炎活性。方法:采用牛津杯法检测酸浆五种部位醇提物对金黄色葡萄球菌、大肠杆菌和枯草芽孢杆菌的抑菌活性;DPPH清除法检测其抗氧化活性;Alamar Blue法检测其对人乳腺癌细胞株MCF-7、MDA-MB-231和肝癌细胞株Bel7402的抑制效果;一氧化氮检测试剂盒测定其抗炎活性。结果:浆果对金黄色葡萄球菌和大肠杆菌的抑菌效果最好,叶对枯草芽胞杆菌抑菌活性较明显,抑菌圈分别为(16.63±0.49)、(14.97±0.37)、(15.83±0.29)mm。宿萼的抗氧化活性最高,浓度为5 mg/m L时对DPPH的清除率为96.79%±2.09%,基本和同剂量的VC效果相当。酸浆各部位醇提物对肿瘤细胞的抑制作用呈现浓度依赖性,其中根对MCF-7的抑制活性较强,宿萼对MDA-MB-231和Bel7402的活性较强,IC50分别为(31.46±1.49)、(48.84±1.69)、(65.48±1.82)μg/m L。叶的抗炎效果最佳,茎抗炎效果较弱,10μg/m L时NO产生量分别为11.01、27.73μmol/L。结论:酸浆具有一定的抑菌、抗氧化、抗肿瘤和抗炎活性,为酸浆的功能开发及活性成分分离提供一定的理论依据。     

橘皮素的提取分离、改性及对人体肝星状细胞LX-2的抑制作用

通过分离纯化及改性得到橘皮素和5-去甲氧基橘皮素,并研究其对人体肝星状细胞株LX-2的抑制作用。通过无水乙醇提取、氯仿萃取从陈皮中得到多甲基黄酮混合物,再以不同浓度的乙酸乙酯和石油醚的混合液为洗脱剂,采用硅胶柱层析分离纯化多甲基黄酮混合物,得到橘皮素纯品。将橘皮素置于盐酸乙醇溶液中回流,对所得产物进行纯化即可得5-去甲氧基橘皮素,采用质谱和核磁共振谱进行结构确证。利用人体肝星状细胞株LX-2细胞作为工具细胞,研究其生物活性。结果表明,5-去甲氧基橘皮素在12.5 μmol/L条件下对人肝星状细胞株LX-2的抑制率即可达到50%,而橘皮素需要在近150 μmol/L条件下才能达到50%的抑制率,即改性后的橘皮素对人体肝细胞的抑制有效率增加了10 倍以上。     

离子交换层析法分离猪股骨降血压肽的研究

猪股骨酶解液经超滤、凝胶层析初步分离后,为了得到高活性且纯度较高的降血压肽,采用离子交换层析对凝胶层析分离后的高活性组分进一步分离。通过对洗脱液p H、离子强度、流速三个因素进行研究,确定了最佳分离条件:以p H=6.0、0.05mol/L磷酸盐缓冲液为A液、B液为含1mol/LNa Cl的p H=6.0、0.05mol/L磷酸盐缓冲液,洗脱流速为0.8m L/min。结果显示:离子交换层析分离得3个组分,其中组分1的活性最高,其IC50值为0.1012mg/m L;再利用凝胶层析将组分1进行脱盐,其峰2的IC50值达到0.0836mg/m L,脱盐率达到86.60%±0.5%。     

乳制品消费与癌症风险控制

乳制品是营养价值很高的食物,但近年来对于乳制品的健康意义有了质疑之声。本文综述了乳制品与结肠癌、乳腺癌、前列腺癌、卵巢癌4种癌症发生风险关系的营养流行病学研究,对近年"牛奶致癌论"作出客观评价。证据表明,乳制品与前列腺癌和卵巢癌可能有一定的正相关性,但研究结果并不一致;乳制品对结肠癌的预防具有益处,对乳腺癌的影响未有定论;尚无证据表明每日摄入200g以下会显著增加癌症的风险。     

红肉及加工肉制品与结直肠癌风险关系的研究进展

近年来我国结直肠癌的发病率和死亡率逐年上升。据研究,结直肠癌发生率的升高可能与红肉及加工肉制品消费的增长具有一定相关性,但该关联性一直存在争议。为此,本文分析了现阶段研究红肉及加工肉制品与结直肠癌相关性的方法及其局限性,并综述了与红肉及加工肉制品相关的潜在结直肠癌致病因素,为确定结直肠癌及其他癌症与红肉及加工肉制品之间的关系提供了新的思路。     

瘦素与癌症

综述瘦素的生物学特性、作用机制及与癌症的关系。     

植物甾醇及其抗癌作用

早期研究证明植物甾醇具有降低血浆胆固醇的作用,随着对植物甾醇的深入研究和广泛应用,人们发现其对多种癌症亦有预防和治疗作用。概述了植物甾醇的抗癌作用和机理。     

Vitamin E and its anticancer effects

Abstract

Vitamin E is a lipid soluble vitamin comprising of eight natural isoforms, namely, α, β, δ, γ isoforms of tocopherol and α, β, δ, γ isoforms of tocotrienol. Many studies have been performed to elucidate its role in cancer. Until last decade, major focus was on alpha tocopherol and its anticancer effects. However, major clinical trials using alpha-tocopherol like SELECT trial and ATBC trial did not yield meaningful results. Hence there was a shift of focus to gamma-tocopherol, delta-tocopherol and tocotrienol. Unlike alpha-tocopherol, gamma-tocopherol and delta-tocopherol can scavenge reactive nitrogen species in addition to reactive oxygen species. Antiangiogenic effect, inhibition of HMG CoA reductase enzyme and inhibition of NF-κB pathway make the anti-cancer effects of tocotrienols unique compared to other vitamin E isoforms. Preclinical research on non-alpha tocopherol isoforms of vitamin E showed promising data on their anticancer effects. In this review, we deal with the current understanding on the potential mechanisms involved in the anticancer effects of vitamin E and the controversies in this field over last three decades. We also highlight the need to conduct further research on the anticancer effects of non-alpha-tocopherol isoforms in larger population and clinical setting.     

Exercise and cancer: Linkages with obesity?

This review examines possible protection against various types of tumors from both occupational and leisure‐time physical activity. A growing number of well‐controlled studies suggest that both hard physical work and an active leisure reduce the overall incidence of cancer. Benefit is demonstrated most clearly for colonic tumors; here, benefit persists after control of the data for body mass index, and a likely mechanism is the speeding of colonic transit, with a resulting decrease in exposure to carcinogens. There are occasional reports of protection against tumors of the breast, reproductive tract, and other body organs. In some of these latter sites, potential mechanisms of protection include a suppression of sex hormone secretion and a reduction of body fat depots, where androgens are converted to toxic estrogen derivatives. While vigorous athletic participation may well modulate hormone output, a reduction of body fat is a more likely explanation of any benefit from more moderate physical activity. Protection against cancer is unlikely to become a major argument for an active lifestyle, but it is nevertheless a useful byproduct of physical activity undertaken with other health objectives.     

Milk and kefir maintain aspects of health during doxorubicin treatment in rats

Doxorubicin (DOX), a powerful anthracycline antibiotic commonly used to treat a wide variety of cancers, is associated with the production of reactive oxygen species that cause oxidative damage, resulting in cardiac dysfunction. Components of dairy may have protective effects against DOX-induced cardiac damage. Kefir is a naturally fermented milk product containing antioxidants, probiotic bacteria, and yeast in addition to the protective components of dairy. We explored the effects of dietary milk and kefir on DOX-induced cardiotoxicity in rats. We used singly housed, 10-wk-old male Sprague Dawley rats assigned to 1 of 3 isocaloric diets, control (CON n = 24), milk (MLK, n = 24), or kefir (KEF, n = 24), with equivalent macronutrient profiles. After a 9-wk dietary intervention, all animals were given either a bolus injection (15 mg/kg) of DOX (CON-DOX n = 12; MLK-DOX n = 12, KEF-DOX n = 12) or saline (CON-SAL n = 12; MLK-SAL n = 12; KEF-SAL n = 12). Body weight, grip strength, echocardiographic evaluation of cardiac geometry, and cardiac function were evaluated using echocardiography at 5 d postinjection and data were analyzed using ANOVA. Survival at d 5 post-DOX injection was 92 and 100% in KEF-DOX and MLK-DOX, respectively, and 75% in CON-DOX. By the last week of the dietary intervention, and just before injection with saline or DOX, CON weighed significantly (14%) more than the MLK and KEF. The DOX treatment resulted in significant reductions in body weight; however, we found no diet × drug interactions. The DOX treatment reduced peak grip strength compared with SAL; when compared with pre-injection measures, MLK-DOX rats did not experience a significant reduction in peak grip strength compared with CON-DOX and SAL-DOX rats. Heart mass in MLK and KEF was significantly higher when compared with CON. In summary, 9 wk of milk or kefir ingestion resulted in lower body size and higher heart mass after DOX treatment. Additionally, MLK preserved peak grip strength after DOX treatment, whereas KEF or CON did not. We observed no consistent protective effects with respect to heart dimensions and function. These findings suggest that long-term milk or kefir ingestion may be helpful in optimizing health before and during doxorubicin treatment.     

番茄红素抗癌作用的研究及进展

番茄红素系烃类类胡萝卜素,具有抗癌和降低癌症发病几率的功能,尤其是胃肠道癌和前列腺癌。目前,流行病学通过对照研究发现,番茄红素主要通过对单线态氧的猝灭作用和诱导细胞间隙连接通讯等机制来抑制癌细胞的生长,使癌症的危险性与其摄入呈负相关。本文就番茄红素的抗癌作用从其分子结构、代谢分布、作用机制和细胞分裂等方面进行研究。     

Dietary Acrylamide and Cancer Risk in Humans: A Review

In April 2002, researchers from the Swedish National Food Administration reported that they had detected elevated levels of acrylamide in commonly consumed baked and fried foods. Acrylamide is known as a neurotoxin in humans and as a carcinogen in experimental animals, and it is classified as a probable human carcinogen by the International Agency for Research on Cancer (IARC, 1994). Therefore, the discovery that the compound forms naturally during high-heat cooking of starchy foods caused substantial alarm in Sweden and worldwide. Within months of the initial Swedish report, national governments and food companies began their own investigations on acrylamide in foods and discussed the potential impact of dietary acrylamide on the public’s health. The discovery also provoked public debate among scientists about the importance of the finding because of the relative lack of data in humans on the one hand and the knowledge that acrylamide in high doses is genotoxic in cell and animal studies on the other. Since 2002, researchers have engaged in a wide range of studies spanning across disciplines. In this review, we summarize the current state of knowledge on acrylamide in foods. We discuss the formation and intake of acrylamide in foods, present evidence for carcinogenicity in cell and animal studies, and examine the findings from epidemiological studies of occupational and dietary exposures. We conclude with a discussion of future directions in the field.

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Zusammenfassung (Redaktion). Im April des Jahres 2002 berichteten Forscher der nationalen, schwedischen Lebensmittelbeh?rde über den erh?hten Gehalt an Acrylamid in gebackenen oder frittierten, üblicherweise verzehrten Lebensmitteln. Acrylamid gilt in Bezug auf den Menschen als Neurotoxin und hat sich in Tierversuchen als karzinogen erwiesen; die International Agency for Research on Cancer (IARC) hat Acrylamid als potenziell karzinogen für den Menschen eingestuft. Daher hat die Entdeckung, dass sich diese Substanz natürlicherweise beim starken Erhitzen von st?rkereichen Lebensmitteln bildet, erhebliche Beunruhigung in Schweden und weltweit ausgel?st. Schon wenige Monate, nachdem der schwedische Report über Acrylamid in Lebensmitteln erschienen war, wurden von den Regierungen verschiedener Staaten und auch von der Lebensmittelindustrie eigene, diesbezügliche Forschungsprogramme veranlasst. Der potenzielle Einfluss des Acrylamids in Lebensmitteln auf die Gesundheit der Bev?lkerung wurde ebenso diskutiert wie die Bedeutung dieser Entdeckung angesichts der Tatsache, dass für Menschen zwar kaum Daten vorliegen, dass aber Acrylamid in hohen Dosen auf Zellkulturen und Versuchstiere genotoxisch wirkt. Seit dem Jahr 2002 ist diesen offenen Fragen im Rahmen mehrerer Disziplin-übergreifender Forschungsvorhaben nachgegangen worden. Im vorliegenden Review wird der derzeitige Wissensstand über Acrylamid in Lebensmitteln vorgestellt. Die Autoren diskutieren die Bildung von Acrylamid in und seine Aufnahme mit Lebensmitteln, besprechen seine karzinogenen Eigenschaften in Versuchen mit Zellkulturen oder Tieren und analysieren die Ergebnisse epidemiologischer Studien. Zukünftige Entwicklungen werden er?rtert.