Anti-influenza virus activity of a lignin fraction from cone of Pinus parviflora Sieb. et Zucc.

When mice were inoculated intranasally or intracerebrally with lethal doses of influenza virus A/WSN/33, most died within 12 days. However, the infectivity of virus that had been preincubated with a lignin prepared from cones of Pinus parviflora Sieb. et Zucc. (PC-Fr. VI) was significantly reduced. Intraperitoneal or oral administration of PC-Fr. VI, prior to virus inoculation, slightly increased the survival ratio of the infected mice. Experiments using radiolabeled PC-Fr. VI revealed that this fraction effectively binds to virions as well as to cultured cells. These data suggest that PC-Fr. VI either inactivates the virus or induces the anti-viral state in cells by binding to virions or cells.