Gilling D H, Kitajima M, Torrey J R, Bright K R
Department of Soil, Water and Environmental Science, The University of Arizona, Tucson, AZ, USA.
J Appl Microbiol. 2014 May;116(5):1149-63. doi: 10.1111/jam.12453. Epub 2014 Feb 12.
To investigate the antiviral efficacy of oregano oil and its primary active component, carvacrol, against the nonenveloped murine norovirus (MNV), a human norovirus surrogate.
Along with an observed loss in cell culture infectivity, the antiviral mechanisms of action were determined in side-by-side experiments including a cell-binding assay, an RNase I protection assay and transmission electron microscopy (TEM). Both antimicrobials produced statistically significant reductions (P ≤ 0·05) in virus infectivity within 15 min of exposure (c. 1·0-log10). Despite this, the MNV infectivity remained stable with increasing time exposure to oregano oil (1·07-log10 after 24 h), while carvacrol was far more effective, producing up to 3·87-log10 reductions within 1 h. Based on the RNase I protection assay, both antimicrobials appeared to act directly upon the virus capsid and subsequently the RNA. Under TEM, the capsids enlarged from ≤35 nm in diameter to up to 75 nm following treatment with oregano oil and up to 800 nm with carvacrol; with greater expansion, capsid disintegration could be observed. Virus adsorption to host cells did not appear to be affected by either antimicrobial.
Our results demonstrate that carvacrol is effective in inactivating MNV within 1 h of exposure by acting directly on the viral capsid and subsequently the RNA.
This study provides novel findings on the antiviral properties of oregano oil and carvacrol against MNV and demonstrates the potential of carvacrol as a natural food and surface (fomite) sanitizer to control human norovirus.
研究牛至油及其主要活性成分香芹酚对无包膜鼠诺如病毒（MNV，一种人类诺如病毒替代物）的抗病毒效果。
随着细胞培养感染性的降低，通过包括细胞结合试验、核糖核酸酶I保护试验和透射电子显微镜（TEM）在内的并行实验确定了抗病毒作用机制。两种抗菌剂在暴露15分钟内均使病毒感染性产生了具有统计学意义的降低（P≤0·05）（约1.0个对数级）。尽管如此，随着暴露于牛至油的时间增加，MNV感染性保持稳定（24小时后为1.07个对数级），而香芹酚的效果要好得多，在1小时内最多可使感染性降低3.87个对数级。基于核糖核酸酶I保护试验，两种抗菌剂似乎都直接作用于病毒衣壳，进而作用于RNA。在透射电子显微镜下，用牛至油处理后，衣壳直径从≤35纳米扩大到75纳米，用香芹酚处理后扩大到800纳米；随着扩张程度增加，可以观察到衣壳解体。病毒对宿主细胞的吸附似乎不受任何一种抗菌剂的影响。
我们的结果表明，香芹酚通过直接作用于病毒衣壳进而作用于RNA，在暴露1小时内可有效灭活MNV。
本研究提供了关于牛至油和香芹酚对MNV抗病毒特性的新发现，并证明了香芹酚作为一种天然食品和表面（污染物）消毒剂来控制人类诺如病毒的潜力。
