Yang Zi-Feng, Bai Li-Ping, Huang Wen-bo, Li Xu-Zhao, Zhao Sui-Shan, Zhong Nan-Shan, Jiang Zhi-Hong
State Key Laboratory of Respiratory Disease (Guangzhou Medical University), The First Affiliated Hospital of Guangzhou Medical University, 151 Yanjiang Road, Guangzhou, China; National Clinical Research Center, Guangzhou, China.
State Key Laboratory of Quality Research in Chinese Medicine, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Taipa, Macau SAR, China.
Fitoterapia. 2014 Mar;93:47-53. doi: 10.1016/j.fitote.2013.12.011. Epub 2013 Dec 24.
Influenza poses a particular risk of severe outcomes in the elderly, the very young and those with underlying diseases. Tea polyphenols are the natural phenolic compounds in teas, and principally consist of catechins, proanthocyanidins, flavonols, and theaflavins, which antiviral activities have been reported recently. This study is to gain a further insight into potential of various tea polyphenols for inhibiting influenza virus infection. Five tea polyphenols exhibited inhibitory activity against influenza A virus in the trend of theaflavin>procyanidin B-2>procyanidin B-2 digallate>(-)-epigallocatechin(EGC)>(-)-epigallocatechingallate(EGCG) with IC50 values in the range of 16.2-56.5 μg/ml. Six of the tested compounds showed anti-influenza B virus activity in the order of kaempferol>EGCG>procyanidin B-2>(-)-EGC~methylated EGC>theaflavin with IC50 values in the range of 9.0-49.7 μg/ml. Based on these results, the structure-activity relationship (SAR) was explained as follows. First, the dimeric molecules, such as theaflavin and procyanidin B-2, generally displayed more potent antiviral activity against both influenza A and B viruses than the catechin monomers. Second, the kaempferol for inhibition of influenza B virus indicated that the more planar flavonol structure with only one C-4' phenolic hydroxyl group in the B ring is necessary for the anti-influenza B virus activity. A similar SAR can be drawn from the assays of another enveloped RNA virus, such as respiratory syncytial virus. These results are expected to provide guides for rational design of antiviral drugs based on polyphenols.
流感对老年人、幼儿以及患有基础疾病的人构成了严重后果的特殊风险。茶多酚是茶叶中的天然酚类化合物，主要由儿茶素、原花青素、黄酮醇和茶黄素组成，最近已有报道称它们具有抗病毒活性。本研究旨在进一步深入了解各种茶多酚抑制流感病毒感染的潜力。五种茶多酚对甲型流感病毒表现出抑制活性，其抑制活性趋势为茶黄素>原花青素B - 2>原花青素B - 2没食子酸酯>(-)-表没食子儿茶素(EGC)>(-)-表没食子儿茶素没食子酸酯(EGCG)，IC50值在16.2 - 56.5μg/ml范围内。六种受试化合物对乙型流感病毒表现出抗流感病毒活性，顺序为山奈酚>EGCG>原花青素B - 2>(-)-EGC~甲基化EGC>茶黄素，IC50值在9.0 - 49.7μg/ml范围内。基于这些结果，结构 - 活性关系(SAR)解释如下。首先，二聚体分子，如茶黄素和原花青素B - 2，通常对甲型和乙型流感病毒都表现出比儿茶素单体更强的抗病毒活性。其次，山奈酚对乙型流感病毒的抑制作用表明，B环中只有一个C - 4'酚羟基的更平面的黄酮醇结构对于抗乙型流感病毒活性是必要的。从另一种包膜RNA病毒，如呼吸道合胞病毒的试验中也可以得出类似的结构 - 活性关系。这些结果有望为基于多酚的抗病毒药物的合理设计提供指导。
