The inhibitory activity of manuka oil against Herpes simplex virus type 1 (HSV-1) and Herpes simplex virus type 2 (HSV-2) was tested in vitro on RC-37 cells (monkey kidney cells) using a plaque reduction assay. In order to determine the mode of antiviral action of the essential oil, manuka oil was added at different times to the cells or viruses during the infection cycle. Both HSV types were significantly inhibited when the viruses were pretreated with manuka oil 1 h prior to cell infection. At non-cytotoxic concentrations of the essential oil, plaque formation was significantly reduced by 99.5 % and 98.9 % for HSV-1 and HSV-2, respectively. The 50 % inhibitory concentration (IC50) of manuka oil for virus plaque formation was determined at 0.0001 % v/v ( = 0.96 μg/mL) and 0.00006 % v/v ( = 0.58 μg/mL) for HSV-1 and HSV-2, respectively. On the other hand, pretreatment of host cells with the essential oil before viral infection did not affect plaque formation. After virus penetration into the host cells only replication of HSV-1 particle was significantly inhibited to about 41 % by manuka oil. Flavesone and leptospermone, two characteristic ß-triketones of manuka oil, inhibited the virulence of HSV-1 in the same manner as the essential oil itself. When added at non-cytotoxic concentrations to the virus 1 h prior to cell infection, plaque formation was reduced by 99.1 % and 79.7 % for flavesone and leptospermone, respectively.
在体外 RC-37 细胞(猴肾细胞)上使用斑块还原法测试了麦卢卡精油对 1 型单纯疱疹病毒(HSV-1)和 2 型单纯疱疹病毒(HSV-2)的抑制活性。为了确定麦卢卡精油的抗病毒作用模式,在感染周期内的不同时间向细胞或病毒中添加了麦卢卡精油。在细胞感染前 1 小时用麦卢卡精油预处理病毒时,两种类型的 HSV 都受到了明显的抑制。在无细胞毒性的精油浓度下,HSV-1 和 HSV-2 的斑块形成率分别显著降低了 99.5% 和 98.9%。对 HSV-1 和 HSV-2 而言,麦卢卡精油对病毒斑块形成的 50% 抑制浓度(IC50)分别为 0.0001 % v/v (= 0.96 μg/mL )和 0.00006 % v/v (= 0.58 μg/mL )。另一方面,在病毒感染前用精油预处理宿主细胞并不会影响斑块的形成。病毒侵入宿主细胞后,只有麦卢卡精油能显著抑制 HSV-1 粒子的复制,抑制率约为 41%。麦卢卡精油中的两种特征性 ß-三
酮类化合物 Flavesone 和 leptospermone 对 HSV-1 病毒的抑制作用与精油本身相同。在细胞感染前1小时,以非细胞毒性浓度添加到病毒中,弗拉维松和leptospermone可分别减少99.1%和79.7%的斑块形成。