A
Kampo medicine,
maoto, has been prescribed in an early phase of
influenza-like illness and used for a treatment of
influenza clinically in Japan these days. However, the efficacy of
maoto against the
virus infection remains to be elucidated. This study was conducted to evaluate the alleviative effects of
maoto against early phase of influenza virus
infection and its preliminary mode of actions through immune systems. When
maoto (0.9 and 1.6 g/kg/day) was orally administered to A/J mice on
upper respiratory tract infection of influenza virus A/PR/8/34 from 4 hours to 52 hours postinfection (p.i.) significant
antipyretic effect was shown in comparison with water-treated control. Administration of
maoto (0.8 and 1.3 g/kg/day) significantly decreased the virus titers in both nasal (NLF) and bronchoalveolar lavage fluids (BALF) at 52 hours p.i., and significantly increased the anti-influenza virus
IgM,
IgA, and
IgG1 antibody titers in NLF, BALF, and serum, respectively.
Maoto also increased significantly the influenza virus-bound
IgG1 and
IgM antibody titers in serum and the virus-bound
IgM antibody titer in even the BALF of uninfected A/J mice. These results indicate that
maoto exerts
antipyretic activity in influenza virus-infected mice and virus reducing effect at an early phase of the
infection through probably augmentation of the virus-bound natural
antibodies.