Inhibition Effects of Patchouli Alcohol, Carvacrol, p-Cymene, Eucalyptol and Their Formulations Against Influenza Virus Pneumonia Through TLR4/NF-κB/NLRP3 Signaling Pathway

As a kind of drug mostly used historically to treat epidemics, aromatic botanicals have volatile oils as active components. The study aims to evaluate the anti-influenza viral pneumonia effects of volatile monomers patchouli alcohol (PA), carvacrol (CV), p-Cymene (PC), eucalyptol (EC) and their formulations from various aspects through the influenza virus A/PR/8/34 (H1N1) infection experiment in vivo and in vitro and carry out in-depth studies on the anti-inflammatory mechanisms. In this study, we found that all four volatile monomers mentioned above could exert antiviral effects by suppressing pulmonary viral load and lung index and improving lung lesions in mice with influenza pneumonia. In addition, elevated levels of cytokines and chemokines in the serum were suppressed, the proportion of T-lymphocytes in the peripheral blood was altered, and antioxidative stress indices were improved, whose mechanism of action related to anti-inflammation, possibly acting on the Toll-Like Receptor 4/Nuclear Factor-κB/nucleotide-binding domain leucine-rich repeat and pyrin domain-containing receptor 3 (TLR4/NF-κB/NLRP3) pathway. The study provides an experimental basis for volatile monomers and their formulations of aromatic herbs for treating influenza virus pneumonia.