Quercetin to enhance the bioavailability and activity of green tea polyphenols

槲皮素增强绿茶多酚的生物利用度和活性

基本信息

批准号：
8641331
负责人：
Susanne Margarete Henning
金额：
$ 7.47万
依托单位：
UNIVERSITY OF CALIFORNIA LOS ANGELES
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-04-01 至 2016-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8641331
关键词：
ABCC1 gene Adverse effects Animals Apple Berry Biological Biological Availability Blood Broccoli - dietary Carrier Proteins Catechol O-Methyltransferase Cell Culture Techniques Cell Line Chemical Structure Chemicals Chemoprevention Chemopreventive Agent Clinical Trials Combined Modality Therapy Consumption CpG Islands Cytosine DNA DNA Methylation DNA Methyltransferase DNA Modification Methylases Data Detection Diagnosis Dose Double-Blind Method Enterohepatic Circulation Enzyme Gene Epigallocatechin Gallate Erythrocytes Evaluation Excretory function Flavonoids Foundations Future Gene Expression Gene Proteins Genes Green tea Hepatotoxicity High Pressure Liquid Chromatography Hour Human Hypermethylation Induction of Apoptosis Intake Intervention Intervention Studies LNCaP MSH3 gene Malignant neoplasm of prostate Marketing Metabolism Methylation Methyltransferase Multi-Drug Resistance Multidrug Resistance Associated Protein 1 Mus Onions Participant Phase Placebo Control Placebos Plasma Prevention Promoter Regions Prostate Prostatectomy Prostatic Neoplasms Public Health Published Comment Quercetin Randomized Research Design SCID Mice Schedule Staging Tea Testing Time Tissues Toxic effect Tumor Tissue Tumor Volume Urine Western Blotting Xenograft procedure absorption arm base capsule carcinogenesis cell growth drinking enzyme activity epicatechin epicatechin gallate epigallocatechin-(4-8,2-O-7)epicatechin gallocatechol genome-wide inhibitor/antagonist men polyphenol prevent prostate cancer model prostatitis protein expression public health relevance subcutaneous sulfation tissue processing tumor tumor growth uptake

项目摘要

DESCRIPTION (provided by applicant): Based on the reviewers' comments and new findings we revised the study design, dose, timing, tissue processing and statistical evaluation. The objective of the proposed human intervention study remains to determine whether a combined administration of quercetin and green tea (GT) will increase the bioavailability and decrease the metabolism of GT polyphenols (GTPs) such as epigallocatechin gallate (EGCG). Factors limiting the biological activity of GTPs are the reduced bioavailability and extensive metabolism converting EGCG into methylated metabolites with decreased activity. In our previous human intervention study in men drinking 6 cups of green tea daily prior to prostatectomy we demonstrated that GTPs are present in human prostate tissue. However 50 percent of EGCG was found in methylated form. Quercetin, a flavonoid found in onions, apples, broccoli, berries and teas is a natural inhibitor of catechol-O-methyltransferase (COMT) and multidrug resistance transport proteins (MRP1 and MRP2). Our cell culture studies demonstrated that the combined treatment with EGCG and quercetin led to a 4 to 10-fold increase in intracellular concentration of EGCG and significant decrease in EGCG methylation, depending on the cell line used. We demonstrated in mouse prostate cancer xenograft studies that the administration of the combination of GT with quercetin significantly decreased tumor volume, increased EGCG tissue concentration and decreased the methylation of EGCG significantly compared to treatment with GT or quercetin alone. The combined administration also significantly decreased the protein expression of methyltransferases and MRP1. We therefore propose a placebo- controlled, double-blinded, randomized, parallel two arm human pilot intervention study to determine whether the consumption of GT extract and quercetin will increase the bioavailability of GTPs in blood and prostate tissue and decrease the methylation of EGCG. We will administer two capsules of GT extract combined with one capsule of quercetin (N=25) or with one placebo capsule (N=15) twice daily for 3 weeks to men scheduled for prostatectomy. After 10 participants will complete the intervention, liver toxicity will be evaluated. In the absence of lier toxicity the quercetin dose will be doubled (800 mg daily) (N=15). GTPs, quercetin and methylated metabolites will be analyzed in blood and prostate tissue using high performance liquid chromatography (HPLC) with coularray electrochemical detection (ECD). To evaluate the mechanism involved, COMT and DNA methyltransferase enzyme activities and gene and protein expression as well as MRP1 gene and protein expression and global DNA methylation will be determined in tumor and normal prostate tissue and COMT activity in erythrocytes using HPLC-ECD, real time qPCR and Western blot analyses. The results will lay the foundation for future clinical trials to evaluate the interaction of quercetin and GT in chemoprevention of early stages of prostate cancer.

描述（由申请人提供）：根据审稿人的评论和新发现，我们修订了研究设计，剂量，时机，组织处理和统计评估。拟议的人干预研究的目的尚未确定槲皮素和绿茶（GT）的综合给药是否会增加生物利用度，并减少GT多酚（GTP）的代谢（例如Epigallocatechin Gallate（EGCG））。限制GTP的生物学活性的因素是降低的生物利用度和广泛的代谢，将EGCG转化为甲基化代谢产物，其活性降低。在先前的人类干预研究中，每天在前列腺切除术前每天喝6杯绿茶的男性中，我们证明了GTP存在于人类前列腺组织中。但是，发现50％的EGCG以甲基化形式发现。槲皮素是一种在洋葱，苹果，西兰花，浆果和茶中发现的类黄酮，是Catechol-O-甲基转移酶（COMT）和多药耐药转运蛋白（MRP1和MRP2）的天然抑制剂。我们的细胞培养研究表明，与EGCG和槲皮素的联合治疗导致EGCG细胞内浓度增加4至10倍，EGCG甲基化显着降低，具体取决于所使用的细胞系。我们在小鼠前列腺癌异种移植研究中证明，与单独使用GT或槲皮素的治疗相比，GT与槲皮素的组合施用显着降低了肿瘤体积，EGCG组织浓度升高，EGCG组织浓度升高并降低EGCG的甲基化。联合给药还显着降低了甲基转移酶和MRP1的蛋白质表达。因此，我们提出了一项安慰剂控制的，双盲的，随机的，平行的两臂人试验干预研究，以确定GT提取物和槲皮素的消耗是否会增加血液和前列腺组织中GTP的生物利用度，并减少EGCG的甲基化。我们将使用两个胶囊与一个槲皮素（n = 25）或一个安慰剂胶囊（n = 15）（n = 15）的两次胶囊进行管理，每天两次，持续3周，安排预定的前列腺切除术。 10名参与者完成干预后，将评估肝毒性。在没有液化毒性的情况下，槲皮素剂量将加倍（每天800毫克）（n = 15）。 GTP，槲皮素和甲基化的代谢产物将使用高性能液相色谱（HPLC）在血液和前列腺组织中进行分析。为了评估所涉及的机制，COMT和DNA甲基转移酶活性以及基因和蛋白质表达以及MRP1基因和蛋白质表达以及全局DNA甲基化将在肿瘤和正常的前列腺组织中，并使用HPLC-ECD，实时QPCR和Western QPCR和Western Blot分析在肿瘤和正常的前列腺组织和COMT活性中确定。结果将为将来的临床试验奠定基础，以评估槲皮素和GT在前列腺癌早期化学预防中的相互作用。