The synthesis of novel cationic anthraquinone dyes with high potent antimicrobial activity

Quaternary ammonium salts were incorporated into anthraquinone dyes via a stable alkyl amino linkage. The structures of the antimicrobial colorants were characterized by Fourier Transform Infrared (FT-IR), Nuclear Magnetic Resonance (NMR) and UV–vis spectrometries. The dyes demonstrated excellent antimicrobial ability against both Gram-negative and Gram-positive bacteria in aqueous solution, as indicated by very low minimum inhibitory concentration (MIC). The colorants showed excellent stability in water under light, continuous heating as well in as acidic and alkaline conditions.