In-Silico Evaluation and Docking of Herbal and Synthetic Antimicrobials Targeting Catalase in Edwardsiella spp.

Edwardsiellosis, caused by Edwardsiella tarda and E. piscicida of the family Enterobacteriaceae, represents a significant disease affecting catfish populations. Concerns regarding the adverse effects of antibiotic usage on health and the environment have prompted a shift in research towards alternative strategies, including targeted therapeutics, vaccination, and the development of disease-resistant stocks. In this context, bioinformatics provides a contemporary approach for the identification and analysis of virulence-associated proteins and their interactions with pharmaceutical agents and plant-derived compounds. Catalase, an enzyme responsible for the decomposition of hydrogen peroxide into water and oxygen, functions as a crucial virulence factor in both E. tarda and E. piscicida. In the present study, virulence protein sequences were retrieved from the UniProt database and subjected to comprehensive structural and functional analyses. Characterisation of catalase proteins from both species indicated favourable solubility, structural stability, hydrophilic nature, and partial thermostability. Homology models of these proteins were constructed using the SWISS-MODEL platform, subsequently validated, and determined to be of high quality. The predicted three-dimensional structures were then employed as receptor molecules in molecular docking analyses using AutoDock and HEX, with a dataset comprising 175 antibacterial phytocompounds. The Z-scores of the models indicated acceptable quality. Docking results identified lutein (Amaranthus viridis), isoginkgetin (Cyperus rotundus), and sciadopitysin (Cyperus rotundus) as the top compounds against E. tarda. For E. piscicida, lutein, ginkgetin (Cyperus rotundus), and isoginkgetin were most effective. These herbal compounds, characterized by low binding free energy, demonstrate the potential to control Edwardsiellosis in aquaculture. This preliminary study highlights promising alternatives to antibiotics, but further validation through in vitro and in vivo trials is necessary.