Study On The Antiviral Activity Of Some Essential Oils

Plant essential oil is a natural mixture of many components and complex structures, and it is one of the active ingredients of natural herbal medicine. The essential oil of plant has many biological functions such as antibacterial, anti- inflammation, anti- virus, anticancer and anti-tumor, antioxidant and so on. In this study, four kinds of essential oils from thyme, oregano, wormwood leaf and clove were chosen for antiviral activity study.This study chose two common disease DNA virus adenovirus?human adenovirus, HAdV? and RNA virus encephalomyocarditis virus?Encephalomyocarditis virus, EMCV? as the research model, and in vitro antiviral activity of essential oil were carried out in the sensitive cell lines HEK293 and Vero by using CPE and MTT method s. Different essential oils on cell maximum non-toxic concentration was screened. Further to find the antiviral mechanism of different essential oils, cell infection virus protection, treatment effect, direct inactivation effect and anti adsorption cells were determined, and the virus titer were used to assess the efficacy. The results for the HAdV research found that, the concentration of 20?L/L of thyme essential oil in vitro was have certain inactivation, and the virus titer declined from 10^5.33TCID₅₀/mL to 10⁴TCID₅₀/mL. When oregano oil concentration is 50 ?L/L, the CPE result showed a protective effect, and the virus titer dropped from 10^4.66TCID₅₀/mL to 10^3.83TCID₅₀/mL. The antiviral activity of EMC V virus was studied in vitro, and was evaluated by CPE and fluorescence quantitative PCR. The results showed that thyme essential oil of concentration range from 25?L/L to 100 ?L/L does not have obvious effect on CPE within 48 hours compared with the positive control group. By using oregano oil concentration ranged from 0.78?L/L to 12.5 ?L/L the phenomenon of obvious did not appear and the lesions virus copy number had been reduced after 48h. These two essential oils can delay the time of virus infecting to cells. In conclusion, the essential oils of thyme and oregano oil have cetain inhibition effect on two viruses. Thymol, the main ingredient of the two essential oils, was chosen for the study of antiviral activity. The results showed that the thymol was one of the effective components of thyme and oregano oil anti human adenovirus, instead of thyme essential oil against EMCV effective components.In summary, thyme and oregano oil have inhibition effect on virus and prevent virus adsorption in vitro. The study provides a theoretical basis for the further research of antiviral activity of plant essential oils.