Henning Susanne M, Aronson William, Niu Yantao, Conde Francisco, Lee Nicolas H, Seeram Navindra P, Lee Ru-Po, Lu Jinxiu, Harris Diane M, Moro Aune, Hong Jenny, Pak-Shan Leung, Barnard R James, Ziaee Hossein G, Csathy George, Go Vay L W, Wang Hejing, Heber David
Department of Pathology, VA West Los Angeles, CA 90073, USA.
J Nutr. 2006 Jul;136(7):1839-43. doi: 10.1093/jn/136.7.1839.
Green and black tea have shown promise in the chemoprevention of prostate cancer. The objective of this study was to determine the bioavailability and bioactivity of tea polyphenols (PP) and theaflavins in human serum and human and mouse tissues. A decaffeinated black tea diet was administered to C57BL/6 mice. PPs and theaflavins were found in the small and large intestine, liver, and prostate in conjugated and free forms. The relative prostate bioavailability of theaflavin was 70% higher than that of epigallocatechin gallate (EGCG). In the second mouse study, a green tea (GT) diet was administered followed by the control diet for 1-5 d. Epicatechin (EC), EGCG, and epicatechin gallate (ECG) concentrations in prostate tissue were significantly decreased after 1 d of consuming the control diet. Epigallocatechin gallate (EGC), however, did not decrease significantly. For the human study, 20 men scheduled for surgical prostatectomy were randomly assigned to consume 1.42 L daily of GT, BT, or a caffeine-matched soda control (SC) for 5 d before radical prostatectomy. Tea PPs were greater in prostate samples from men consuming BT and GT than in men consuming SC (P = 0.0025). Although tea PP were not detectable in serum, ex vivo LNCaP prostate cancer cell proliferation was less when cells were grown in media containing patient serum collected after BT (P < 0.001) and GT (P = 0.025) consumption relative to baseline serum This is the first human study to show that tea polyphenols and theaflavins are bioavailable in the prostate where they may be active in the prevention of prostate cancer.
绿茶和红茶在前列腺癌的化学预防方面已显示出前景。本研究的目的是确定茶多酚（PP）和茶黄素在人血清以及人和小鼠组织中的生物利用度和生物活性。给C57BL/6小鼠喂食脱咖啡因红茶饮食。在小肠、大肠、肝脏和前列腺中发现了结合型和游离型的PP和茶黄素。茶黄素在前列腺中的相对生物利用度比表没食子儿茶素没食子酸酯（EGCG）高70%。在第二项小鼠研究中，先给小鼠喂食绿茶（GT）饮食，然后再喂食对照饮食1 - 5天。食用对照饮食1天后，前列腺组织中的表儿茶素（EC）、EGCG和表儿茶素没食子酸酯（ECG）浓度显著降低。然而，表没食子儿茶素（EGC）浓度没有显著下降。在人体研究中，20名计划接受前列腺切除术的男性在根治性前列腺切除术前5天被随机分配，每天饮用1.42升GT、BT或咖啡因含量匹配的苏打水对照品（SC）。食用BT和GT的男性前列腺样本中的茶PP含量高于食用SC的男性（P = 0.0025）。尽管血清中未检测到茶PP，但与基线血清相比，当LNCaP前列腺癌细胞在含有食用BT（P < 0.001）和GT（P = 0.025）后采集的患者血清的培养基中生长时，其体外增殖较少。这是第一项表明茶多酚和茶黄素在前列腺中具有生物利用度且可能在预防前列腺癌方面发挥作用的人体研究。
