科學家證實了在綠茶中的有益健康的物質——它們以強大的抗氧化和抗病性質而知名——確實能滲透到眼組織中。他們的一份新的報告首次記錄了晶狀體、視網膜和其他眼組織如何吸收這些物質,這增加了用綠茶預防青光眼和其他常見眼病的可能性。該報告發表在了美國化學會的《農業與食品化學雜誌》雙周刊上。
Chi Pui Pang及其同事指出,所謂的綠茶「兒茶素」是許多被認為能夠保護眼睛的抗氧化劑之一。這些抗氧化劑包括維生素C、維生素E、葉黃素和玉米黃素。然而,迄今為止,沒有人知道綠茶中的兒茶素是否真正能夠從胃腸道進入眼組織。
Pang和他的同事用喝綠茶的實驗室大鼠的實驗解決了這種不確定。對眼組織的分析表明,眼的結構無疑吸收了顯著數量的某些兒茶素。例如,視網膜吸收了最高濃度的沒食子兒茶素,而房水傾向於吸收表沒食子兒茶素。綠茶兒茶素在減少眼的有害氧化脅迫的效果持續了至多20小時。這份報告得出結論說:「我們的結果顯示喝綠茶可能幫助眼睛應對氧化脅迫」。(生物谷Bioon.com)
生物谷推薦原文出處:
J. Agric. Food Chem. DOI: 10.1021/jf9032602
Green Tea Catechins and Their Oxidative Protection in the Rat Eye
Kai On Chu??, Kwok Ping Chan?, Chi Chiu Wang?, Ching Yan Chu?, Wai Ying Li?, Kwong Wai Choy?, Michael Scott Rogers? and Chi Pui Pang*?
1 Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, Kowloon, Hong Kong
2 Department of Obstetrics and Gynecology, Prince of Wales Hospital, Shatin, New Territories, Hong Kong.
Catechins, active constituents of green tea, are well-known antioxidative natural products. It was proposed that green tea extract (GTE) consumption could benefit the eye, and the pharmacokinetics of catechins and oxidation status in rat eye were investigated after oral administration. Sprague?Dawley rats were fed GTE and sacrificed at different time intervals. Their eyes were dissected into cornea, lens, retina, choroid-sclera, vitreous humor, and aqueous humor for analysis of catechins and 8-epi-isoprostane by HPLC-ECD and GC-NCI-MS, respectively. Catechins were differentially distributed in eye tissues. Gallocatechin was present at the highest concentration in the retina, 22729.4 ± 4229.4 pmol/g, and epigallocatechin in aqueous humor at 602.9 ± 116.7 nM. The corresponding area-under-curves were 207,000 pmol × h/g and 2035.0 ± 531.7 nM × h, respectively. The time of maximum concentration of the catechins varied from 0.5 to 12.2 h. Significant reductions in 8-epi-isoprostane levels were found in the compartments except the choroid-sclera or plasma, indicating antioxidative activities of catechins in these tissues.