(1.江西农业大学 食品科学与工程学院, 江西 南昌 330000;2.浙江省疾病预防控制中心, 浙江 杭州 310051;3.浙江中医药大学 医学技术学院, 浙江 杭州 310053)
(1.College of Food Science and Engineering,Jiangxi Agricultural University, Nanchang 330000, China;2.Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, China;3.College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou 310053, China)
In order to study the inhibitory effect of propolis extract on human norovirus in vitro, murine norovirus and phage MS2 virus were used as alternative viruses to study the inhibitory effect and mechanism of propolis aqueous extract and ethanol extract at different concentrations and time. Concentration-dependent experiments showed that the titers of murine norovirus and MS2 viruses decreased significantly with the increasing concentration of propolis ethanol extract. When the mass concentration of propolis ethanol extract reached 500μg/mL, the titers of murine norovirus and MS2 viruses decreased by 6.93 lgPFU/mL and 3.75 lgPFU/mL, respectively. The time-correlation experiment showed that during murine norovirus and MS2 for 60 min culturing with 250μg/mL propolis ethanol extract, the virus titers of murine norovirus and MS2 decreased by 4.18 lgPFU/mL and 3.30 lgPFU/mL in the first 40min, and then slowed down. After culture for 60min, the total titers of murine norovirus and MS2 decreased by 4.48 lgPFU/mL and 3.67 lgPFU/mL, respectively. Mechanism studies had shown that propolis ethanol extract may bind to host cells (receptors) or directly bind to virus particles to denature viral capsid proteins and prevent viruses from entering host cells. Images taken by transmission electron microscope further confirmed that propoils ethanol extract directly acted on the virus and triggered expansion and rupture. Finally, after propolis ethanol extract treatment, the titer of virus in the vegetable and fruit juices contaminated with man-made virus was significantly reduced. The results of this study might provide more options for selecting suitable additives in fresh pressing process of fruits and vegetables.