Antimicrobial Agents

Coumarin derivatives are among the most intensely examined class of compounds in consideration of a proficient effective drug for microbial diseases. This chapter describes the structure-activity relationships (SARs) of coumarin derivatives associated with the various functional groups and position of coumarin for its antibacterial, antivirus, and antifungal activity. Antibacterial agents: At C3 position on the coumarin ring, the presence of ethylene moiety with carboxylic or tertiary amines group, alkoxyimino group, carbonyl group, hydroxamate group, and benzyl group with hydroxyl or halide group substitution is effective. Similarly, at C4 position, the methyl group, halogen-substituted iodinated aryloxymethyl group, thiotriazo derivatives are effective. Nitro group at C5 position is active. Whereas at C7 position, the carbomoyl group, complex alkoxy group substituted with electron withdrawing group, biphenyl groups are significant. Furanocoumarin substituted with nitro group, and at C8 position methyl group is effective for antibacterial activity. Antiviral agents: Planarity of coumarin ring and methyl group substitution on coumarin ring are important for antiviral agents. Methyl-substituted benzimidazole nucleus or D-ribofuranose group at C3 position of coumarin showed the prominent antiviral activity. Substituted heterocyclic group with -SCH2 linkage was also found as important for bioactivity. Antifungal agents: For effective antifungal activity, nitro group at C3 position is significant, whereas at C4 position the acetyl group is effective. At C6 position both nitro and acetyl groups are active, and at C7 position, the small alkoxy aliphatic chain, phenyl group, acetyl group, and nitro group are prominent.