4-O-Methylepisappanol
4-O-Methylepisappanol (compound 9) is nature product that could be isolated from heartwood of Caesalpinia sappan. 4-O-Methylepisappanol is a potent neuraminidase inhibitor on the surface of influenza viruses with IC50 values of 42.8, 63.2, and 63.2 uM for A/Chicken/Korea/MS96/96 [H9N2], A/PR/8/34 [H1N1], and A/Hong Kong/8/68 [H3N2], respectively[1].