Anti-influenza virus activity of plant flavonoid, 5,7,4′-trihydroxy-8-methoxyflavone, from the roots of scutellaria baicalensis and enhancement of its activity by drug delivery system (DDS): T. Nagaia, Y. Nishibeb, Y. Makinob, T. Tomimoric and H. Yamadaa aOriental Medicine Research Center, The Kitasato Institute, Tokyo 108, Japan, bPharmaceutical Products Research Laboratories, Teijin Limited, Tokyo 191, Japan and cSchool of Pharmacy, Hokuriku University, Kanazawa 920-11, Japan