Synthesis and anti-biofouling properties of hydroxycoumarin and nitrohydroxycoumarin derivatives

In the quest for novel antibiofoulants, 7-hydroxy-4-methylcoumarin (compound 1) and its nitro derivatives 6-nitro-7-hydroxy-4-methyl coumarin (compound 2) and 8-nitro-7-hydroxy-4-methyl coumarin (compound 3) were synthesized with high yields, offering promising opportunities for the development of biologically active materials. These compounds were thoroughly characterized and their chemical structures confirmed using spectroscopic techniques such as nuclear magnetic resonance spectrometry, ultraviolet–visible spectroscopy and Fourier-transform infrared spectroscopy. To evaluate their potential as anti-biofouling agents, antibacterial assays were carried out against two common fouling bacteria, Pseudomonas aeruginosa (Gram-negative), and Staphylococcus aureus (Gram-positive). Compound (1) and Compound (3) exhibit excellent activities against Pseudomonas aeruginosa and Staphylococcus aureus , while compound (2) shows moderate activity. In conclusion, compound (3) proved to be the most effective, in inhibiting the bacterial growth. These findings underscore the antibacterial efficacy of these synthesized coumarin derivatives and highlight in particular the potent activity of compound (3). The surface modification studies utilizing these coumarin derivatives demonstrated promising anti-biofouling properties against clinically relevant pathogens on different substrates. These findings present significant implications for developing anti-adhesive surfaces, such as anti-biofouling coatings and for the healthcare applications, particularly for medical devices, implants and diagnostic platforms, where bacterial colonization remains a critical concern.