Abstract: Coumarin derivatives are pyranocoumarins of formula 2 and coumarin-sulfonamides of formula 3, respectively, wherein R1 is 4-NO2C6H4 or 2-Furyl; R2 is CN or CONH2; R3 is NH2, NCHN(CH3)2 or NCHR6; R4 is Cl or CH3; R5 is SO2NHR7, H, OH, COCH3 or COC2H2R8; R6 is C6H5, 3,4,5-(CH3O)3C6H2 or 2,4-Cl2C6H3; R7 is H, 1,3-thiazole, or 1,3-diazine and R8 is 4-O2NC6H4, 4-CH3OC6H4, or 4-ClC6H4; and pharmaceutically acceptable salts thereof. The coumarin derivatives and pharmaceutical compositions including one or more of such derivatives may by synthesized and used to treat or prevent inflammation or microbial infection, and to reduce levels of reactive oxidative species.