Evers David L, Chao Chih-Fang, Wang Xin, Zhang Zhigang, Huong Shu-Mei, Huang Eng-Shang
Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, NC 27599-7295, USA.
Antiviral Res. 2005 Dec;68(3):124-34. doi: 10.1016/j.antiviral.2005.08.002. Epub 2005 Sep 15.
We report antiviral activity against human cytomegalovirus for certain dietary flavonoids and their likely biochemical mechanisms of action. Nine out of ten evaluated flavonoids blocked HCMV replication at concentrations that were significantly lower than those producing cytotoxicity against growing or stationary phase host cells. Baicalein was the most potent inhibitor in this series (IC(50)=0.4-1.2 microM), including positive control ganciclovir. Baicalein and genistein were chosen as model compounds to study the antiviral mechanism(s) of action for this series. Both flavonoids significantly reduced the levels of HCMV early and late proteins, as well as viral DNA synthesis. Baicalein reduced the levels of HCMV immediate-early proteins to nearly background levels while genistein did not. The antiviral effects of genistein, but not baicalein, were fully reversible in cell culture. Pre-incubation of concentrated virus stocks with either flavonoid did not inhibit HCMV replication, suggesting that baicalein did not directly inactivate virus particles. Baicalein functionally blocked epidermal growth factor receptor tyrosine kinase activity and HCMV nuclear translocation, while genistein did not. At 24h post infection HCMV-infected cells treated with genistein continued to express immediate-early proteins and efficiently phosphorylate IE1-72. However, HCMV induction of NF-kappaB and increases in the levels of cell cycle regulatory proteins--events that are associated with immediate-early protein functioning--were absent. The data suggested that the primary mechanism of action for baicalein may be to block HCMV infection at entry while the primary mechanism of action for genistein may be to block HCMV immediate-early protein functioning.
我们报告了某些膳食类黄酮对人巨细胞病毒的抗病毒活性及其可能的生化作用机制。在评估的十种类黄酮中，有九种在浓度显著低于对生长或静止期宿主细胞产生细胞毒性的浓度时，就能阻断人巨细胞病毒的复制。黄芩苷是该系列中最有效的抑制剂（半数抑制浓度[IC(50)] = 0.4 - 1.2微摩尔），包括阳性对照更昔洛韦。选择黄芩苷和染料木黄酮作为模型化合物来研究该系列的抗病毒作用机制。这两种类黄酮都显著降低了人巨细胞病毒早期和晚期蛋白的水平以及病毒DNA的合成。黄芩苷将人巨细胞病毒即刻早期蛋白的水平降低到几乎背景水平，而染料木黄酮则没有。在细胞培养中，染料木黄酮的抗病毒作用是完全可逆的，而黄芩苷则不是。用任何一种类黄酮对浓缩病毒原液进行预孵育都不会抑制人巨细胞病毒的复制，这表明黄芩苷不会直接使病毒颗粒失活。黄芩苷在功能上阻断了表皮生长因子受体酪氨酸激酶活性和人巨细胞病毒的核转运，而染料木黄酮则没有。在感染后24小时，用染料木黄酮处理的人巨细胞病毒感染细胞继续表达即刻早期蛋白并有效地磷酸化IE1 - 72。然而，人巨细胞病毒诱导的核因子κB以及细胞周期调节蛋白水平的增加（这些事件与即刻早期蛋白的功能相关）却不存在。数据表明，黄芩苷的主要作用机制可能是在病毒进入时阻断人巨细胞病毒感染，而染料木黄酮的主要作用机制可能是阻断人巨细胞病毒即刻早期蛋白的功能。
