Inhibition of Mouse Liver Sialidase by the Root ofScutellaria baicalensis

Of 266 Chinese crude drugs, the hot water extract from the root of Scutellaria baicalensis showed potent mouse liver sialidase inhibitory activity; in addition, wogonin, wogonin glucuronide, baicalein, and baicalin were identified as the inhibitors. These flavonoids showed almost the same inhibitory activity when 50-125 micrograms/ml doses of the samples were used for the assay, while wogonin and baicalein showed a more potent activity than wogonin glucuronide and baicalin at the lower concentration (10 micrograms/ml). However, these flavonoids, except wogonin, showed negligible inhibitory activity against Arthrobacter ureafaciens sialidase. These results indicated that S. baicalensis extract contains the sialidase inhibitors which are specific to mouse liver sialidase.