Antiviral activity of methylelaiophylin, an alpha-glucosidase inhibitor. 
Methylelaiophylin isolated from Streptomyces melanosporofaciens was selected as an alpha-glucosidase inhibitor with an IC50 value of 10 micrometer.  It showed mixedtype inhibition of alpha-glucosidase with a Ki value of 5.94 micrometer.  In addition, methylelaiophylin inhibited the intracellular trafficking of hemagglutinin-neuramidase (HN), a glycoprotein of Newcastle disease virus (NDV), in baby hamster kidney (BHK) cells.  Methylelaiophylin inhibited the cell surface expression of NDV-HN glycoprotein without significantly affecting HN glycoprotein synthesis in NDV-infected BHK cells.