Comparative Studies on Antibacterial Potentials of Cassia fistula and Carica papaya Leaf Extract against Selected Fish Pathogens

Aim: To investigate the antibacterial efficacy of Cassia fistula and Carica papaya leaf extracts against selected fish pathogens such as Aeromonas hydrophila, Vibrio parahaemolyticus, Staphylococcus aureus, Proteus mirabilis and Micrococcus luteus, Study Design: To carry out the antibacterial sensitivity studies of C. fistula and C. papaya leaf extracts using one way analysis of variance. Place and Duration of Study: Department of Biological Sciences, Bells University of Technology, Ota, Ogun State, between November 2022-April, 2023 Methodology: Leaves were subjected to aqueous extraction, and concentrated at 500C in hot air oven. The extracts were screen for biomolecules responsible for antibacterial activities. Antibacterial sensitivity test was carried out on bacteria pathogens using agar well diffusion technique. Results: Results showed that C. fistula leaf extract was more effective against A. hydrophila (20.00b ± 2.31 mm) and P. mirabilis (17.00b ± 1.15 mm) than C. papaya leaf extract. (14.00c ± 2.31 mm and 15.00c ± 1.15 mm), while C. papaya was only effective against V. parahaemolyticus (17.50b ±1.73 mm) than C. fistula (15.50c ± 0.58 mm). The results depicted significant difference (P˂0.05) in the inhibition zone among A. hydrophila, V. parahaemolyticus and P. mirabilis, except S. aureus (12.50b ± 1.73 mm) and M. luteus (11.50b ± 0.58 mm) (P˃0.05). Minimum Inhibitory Concentrations and Minimum Bactericidal Concentrations confirmed that C. fistula was more effective on A. hydrophila than C. papaya at a lesser dose with a marked difference (P˃0.05). Conclusion: C. fistula leaf extract exhibited higher antibacterial efficacy than C. papaya, showing that it is more effective against all tested bacteria except V. parahaemolyticus. This implies that C. fistula is an excellent antibacterial agent with capacity to destroy a wide range of bacteria than C. papaya. Therefore, it can be used to treat fish diseases and pond water against bacteria pathogens, including multidrug resistant bacteria.