Anti-influenza virus effects of the aqueous extract from Mosla scabra.

BACKGROUND

Mosla scabra (Thunb.) C. Y. Wu is a broadly used species in the southeastern China as an antipyretic and antiviral drug for the treatment of colds, fever, inflammation and chronic bronchitis.

OBJECTIVE

To investigate the anti-influenza virus activities of the aqueous extract from Mosla scabra (AEMS), and to provide evidence for the implication of its immunomodulatory potential for the overall protective effect in lethal murine experimental influenza A infection.

METHODS

The anti-influenza virus activities of AEMS or ribavirin were evaluated in embryonated eggs and in a mouse infection model and the effects of AEMS on early immune responses during influenza virus infection were evaluated in a mouse infection model.

RESULTS

At the concentration of 0.3-30.0mg/ml, AEMS exhibited both preventive and therapeutical effect on embryonated egg. Oral administration of AEMS to mice infected with influenza virus A (IVA) was highly effective in preventing death, inhibiting pneumonia and reducing lung viral titers. It also significantly enhanced IFN-gamma, IL-2, IL-4 and IL-5 cytokine-producing splenocytes, increased T-cell subsets like CD4(+) and CD4(+)/CD8(+), decreased levels of IL-6 after infection, and provided protective immunity. At a dosage of 4800 mg/kg, almost all treated mice survived, suggesting that AEMS is of low toxicity. However, ribavirin has weaker efficacy compared to AEMS.

CONCLUSIONS

These results showed, for the first time, while both AEMS and ribavirin appeared to have similar efficacy against IVA, AEMS playing a role as an immunomodulator and antiviral inhibitor during influenza virus infection, was considered to be less toxic and may warrant further evaluation as a possible agent for the treatment of influenza.