Comparative Study of Antibacterial and Antibiofilm Activities of Seed Extracts and Their Phytofabricated Silver Nanoparticles Against Ocular Bacterial Isolates

Abstract

Ocular infections, especially those related to contact lens usage, are often caused by biofilm-forming bacteria that display resistance to conventional antibiotics. This study investigates the antibacterial and antibiofilm potential of seed extracts—Coriandrum sativum (coriander), Piper nigrum (white pepper), and Triphala—and their Phyto fabricated silver nanoparticles (AgNPs) against Pseudomonas aeruginosa and Citrobacter sp., two key ocular pathogens. Clinical samples were collected from infected eyes, contact lenses, and their cases after obtaining informed consent. Bacterial strains were isolated and identified using morphological, cultural, and biochemical methods. Their biofilm-forming abilities were assessed quantitatively. Crude seed extracts were prepared and evaluated for antibacterial efficacy using the agar well diffusion and MIC methods. Silver nanoparticles were synthesized using green synthesis protocols and characterized through UV-Vis spectroscopy and SEM analysis. The plant extracts exhibited inhibition zones of 22 mm and 18 mm against Pseudomonas aeruginosa and Citrobacter sp., respectively. Phyto fabricated AgNPs demonstrated significantly enhanced activity, showing inhibition zones of 25 mm and 20 mm at an MIC of 0.156 mg/mL, outperforming the standard antibiotic moxifloxacin (18 mm and 17 mm respectively). This highlights the potential of AgNPs in overcoming antibiotic resistance and disrupting bacterial biofilms. In conclusion, the Phyto fabricated silver nanoparticles showed superior antibacterial and antibiofilm properties compared to both crude extracts and conventional antibiotics. These findings underscore the promise of integrating plant-based therapeutics with nanotechnology for effective management of ocular infections. Further exploration into mechanism of action and cytocompatibility is recommended to translate this research into ophthalmic applications.