In vitro study on the inhibitory effect of various essential oils against murine coronavirus mouse hepatitis virus A-59 replication

Background The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) worldwide has become one of the biggest health problem due to the lack of knowledge about an effective therapy. Purpose Some scientific studies have shown that EOs have anti-inflammatory, immunomodulatory, and antiviral properties. Study Design This study demonstrated the potential antiviral activity of essential oils (EOs) in emulsion and in vapor forms to reduce the replication of MHV-A59, a murine surrogate of SARS-CoV-2. Methods In present study, 32 EOs and 12 pre-blends EOs made by Aliksir were screened in vitro against MHV-A59 on DBT cells using plaque assay. EOs in emulsions were applied at their maximum noncytotoxic concentrations to MHV-A59 after penetration of the viruses into the host cells for 1 h during intracellular virus replication. Results Monarda didyma at 5000 ppm and pre-blend Complex 095-bleue at 20000 ppm showed a reduction of 100% of viral plaque. Tanacetum annuum at 10000 ppm inhibited 5.03-log MHV-A59, and pre-blend Gardien Complex at 10000 ppm inactivated 4.88-log. Beyond 4-log, the drug can be qualified as an antiviral according to the guidelines of ICH. In vapor form, none of the EOs showed potential inhibitory effects against MHV-A59. Conclusion Results demonstrated that all 44 undiluted EOs, incubated with MHV-A59 for 30 min, had a ≤1.09-log inactivation compared to an untreated virus. The findings of this study may provide proof-of-concept and insight into related trials.