| 摘要: | 嚴重特殊傳染性肺炎是一種由冠狀病毒引起的特殊傳染病，於 2019 年底在中國武漢首次發現，並於 2020 年至 2022 年期間迅速傳播到世界各地，2022 年造成全球至少 600 萬人死亡。COVID-19可以通過其棘蛋白與血管緊張素轉換酶 2 (ACE2) 的結合來感染至宿主，而這種結合可以通過營養物質來調節。眾所周知，臺灣茶中不但擁有許多的機能性成分，甚至其品種繁多，並且經過不同的發酵過程，可加工製成綠茶、包種茶、烏龍茶和紅茶。因此，本論文的目的是研究臺灣茶對 COVID-19 與 ACE2 受體結合的調節作用，以及描述茶多酚對結合能力的影響。使用COVID-19之武漢株病毒，我們發現從臺茶17號和臺茶18號品種中加工製成的綠茶、包種茶、GABA 烏龍茶和紅茶的萃取物可以抑制棘蛋白與 ACE2 受體結合。臺茶18號 茶萃取物的效果比臺茶17號 茶萃取物更有效，並且綠茶比其他發酵度的茶類效果更好。從臺茶12號、臺茶20號和 臺茶22號品系中加工和萃取分離的其他臺灣茶之萃取物也可以抑制 COVID-19 的受體結合域 (RBD) 與 ACE2 之間的結合能力。更進一步的表兒茶素多酚類對RBD 與 ACE2 之間的結合能力的研究表明，表沒食子兒茶素沒食子酸酯(EGCG) 比其他兒茶素多酚類結構相關的 C、CG、EC、ECG、EGC、GC 和 GCG 更能有效地抑制棘蛋白與 ACE2 受體結合，這表明了兒茶素特異性作用。此外，茶黃素二沒食子酸酯(TF3)比其他茶黃素多酚類結構相關的TF、TF2A 和 TF2B 更能有效地抑制棘蛋白與 ACE2 受體的結合，這也表明了茶黃素的特異性作用。咖啡酸對結合沒有顯著性影響。當檢測 COVID-19 的變種株時，我們發現從上述品系中分離的茶萃取物能夠抑制所有 α、β、δ 和 ο 變種株與 ACE2 受體的結合。此外，發現 EGCG 和 TF3 可抑制所有變種株與 ACE2 受體的結合。總而言之，臺灣茶對 COVID-19 與 ACE2 受體結合的抑制作用雖然會因為茶品系、茶發酵程度和所含有的多酚類類型而有所差異，但是對於 COVID-19 與 ACE2 受體結合的抑制作用均有一定抑制效果。本研究的結果支持使用臺灣茶和茶多酚作為預防宿主感染 COVID-19 的潛在用途。
;Coronavirus disease 2019 (COVID-19) is a coronavirus that was first found in Wuhan, China in late 2019 and quickly spread over the world from 2020-2022 to cause at least 6 million people deaths in 2022. The infection of COVID-19 to the host could be determined by the binding of its spike protein with receptor so-called angiotensin-converting enzyme 2 (ACE2), and such a binding can be regulated by nutrients. Taiwan tea (Camellia sinensis) possesses many well-known functional ingredients, contains many varieties, and can be processed into green tea (unfermented tea), paochong tea (light fermented tea), oolong tea (light fermented tea) and black tea (full fermented tea) through different processes of fermentation. The objective of the present thesis was thus designed to investigate Taiwan tea modulations of the COVID-19 binding to the ACE2 receptor, as well as delineating the effects of tea polyphenols on the binding capacity. Using Wuhan strain of COVID-19 virus, we found that the extracts of green tea, paochong tea, GABA oolong tea, and black tea, in which were isolated from tea cultivar of TTES #17 and #18, could inhibit the binding of its spike protein with the ACE2 receptor. The effect of TTES #18 tea extract seemed to be more effective than TTES #17 tea extract, and green tea was more effective than other tea types. The extracts of other Taiwan teas isolated from TTES #12, TTES #20, and TTES #22 cultivar could also inhibit the binding ability between receptor binding domain (RBD) of COVID-19 and ACE2. Further polyphenol study indicated that EGCG was more effective than other structure-related C, CG, EC, ECG, EGC, GC, and GCG to suppress the binding of spike protein with ACE2. This suggests the catechin-specific effect. In addition, TF3 was more effective than TF, TF2A, and TF2B to inhibit the binding of the spike protein with ACE2, suggesting the theaflavin-specific effect. Caffeic acid had no effect on the binding. When the variants of COVID-19 was examined, we found that the tea extracts isolated from above cultivar were able to inhibit the binding of all the α, β, δ and ο variants to the ACE2 receptor. Moreover, EGCG and TF3 were found to inhibit the binding of all the variants to the ACE2 receptor. These results suggest that the inhibitory effect of Taiwan teas on the binding of COVID-19 to the ACE2 receptor varies with tea strain, the status of tea fermentation, and types of polyphenols. The results of this study support the potential use of Taiwan teas and tea polyphenols as the prevention of the host from COVID-19 infection. |
