目的 考察桂枝挥发油及其主要成分桂皮醛体外对甲型流感病毒鼠肺适应株A/PR/8/34（H1N1）的直接杀灭作用，探讨其抗流感病毒作用机制中Toll样受体7（TLR7）信号通路的作用。方法 以流感病毒感染的狗肾传代细胞（MDCK）为载体，测定桂枝挥发油及桂皮醛体外抑制流感病毒增殖的半数抑制浓度（IC₅₀）和治疗指数（TI）；ELISA法检测MDCK细胞干扰素-β（IFN-β）的分泌；RT-PCR法考察MDCK细胞中Toll样受体3（TLR3）、TLR7、肿瘤坏死因子受体相关因子3（TRAF-3）、白介素-1受体相关激酶4（IRAK-4）、IFN-β基因的表达。结果 桂枝挥发油及桂皮醛对流感病毒有明显的直接杀灭作用，IC₅₀分别为1.85×10^?7、5.77×10^?7 g/mL，TI分别为27.04、9.51。与病毒组比较，桂枝挥发油和桂皮醛0.25×10^?5 g/mL显著升高感染甲型流感病毒的MDCK细胞上清液中IFN-β的量（P＜0.05），显著上调细胞中TLR7、IRAK-4、IFN-β mRNA表达水平（P＜0.05）。结论 桂枝挥发油及桂皮醛对流感病毒H1N1的增殖有显著抑制作用，作用机制可能与其激活TLR7信号通路、活化IRAK-4、诱导IFN-β高表达有关。

Objective To study the anti-influenza virus A/PR/8/34 (H1N1) activity of the volatile oil in Cinnamomi Ramulus (VOCR) and cinnamaldehyde in vitro, and to reveal the effect of TLR7 signaling pathway in anti-influenza. Methods The IC₅₀ and therapeutic index (TI) of VOCR and cinnamaldehyde in vitro were determined using influenza virus-infected Madin-Darby canine kidney (MDCK) cell line. ELISA was conducted to determine the level of interferon-β (IFN-β) in MDCK cells. The real-time RT-PCR was used to determine the mRNA expresstion of TLR3, TLR7, TRAF-3, interleukin-1 related acceptor kinase-4 (IRAK-4), and IFN-β. Results Both VOCR and cinnamaldehyde had the direct virucidal activities on influenza virus; The IC₅₀ values were 1.85 × 10^?7 and 5.77 × 10^?7 g/mL, respectively. The TI values were 27.04 and 9.51, respectively. Compared with the virus group, VOCR and cinnamaldehyde (0.25 × 10^?5 g/mL) had the significant effects on increasing the serum level of IFN-β in infected MDCK cells (P < 0.05) and the mRNA expression of TLR7, IRAK-4, and IFN-β (P < 0.05). Conclusion VOCR and cinnamaldehyde have good anti-influenza virus activities in the cellular level. The mechanisms are related to the activiation of TLR7 signaling pathway and IRAK-4, and leading to the high expression of IFN-β.

国家自然科学基金资助项目（30973923，8173637）；“2010年度高层次留学人才回国资助人选”项目（国家人社部人社厅函[2010] 411号）；2010年度留学回国人员科技活动项目择优资助项目（国家人社部人社厅函[2010]412号）；四川省教育厅培育项目（12ZB037）