Efficacy of Moringa oleifera leaves extracts as a natural treatment for marine parasite and bacterial pathogens

Background: Pathogens such as bacteria and parasites are major contributors to losses in aquaculture production. Chemical treatments were commonly used; however, they can have hazardous effects on humans, other animals, and the environment. Purpose: Therefore, there is a demand for safe treatment agents that can substitute toxic treatments while enhancing aquaculture productivity. This research aims to evaluate the potential of Moringa oleifera leaves as a natural treatment against parasitic and bacterial pathogens. Methods: Three concentrations, 100, 50, and 25 mg/ml of methanolic and ethanolic M. oleifera leaves extracts were prepared and tested on marine leech, Zeylanicobdella arugamensis. It was also tested on bacteria, Vibrio alginolyticus, V. parahaemolyticus, V. anguillarum, Photobacterium damselae, Aeromonas salmonicida, and A. hydrophila. Results: GCMS analysis identified Moringa leaves methanolic extract has major compounds of tetradecane, 5-methyl- (25.30 %) and 2-Bromotetradecane (20.76 %) and ethanolic extract has 2-Bromotetradecane (52.07 %). Minimum Inhibitory Concentration (MIC) was 200 mg/ml and 300 mg/ml concentration of methanol and ethanol extracts effective against P. damsalae, respectively. All the leeches resulted in 100 % mortality in five treatments, methanol 100, 50, 25, ethanol 100, and 50 mg/ml with average mortality time of 5.88 ± 0.45, 28.74 ± 7.34, 59.70 ± 6.31, 7.48 ± 2.15, and 18.62 ± 2.97 min, respectively, while only ethanol 25 mg/ml had 80 % mortality rate with the average mortality time of 33.91 ± 8.14 min. Discussion: Thus, this study indicates that the methanol and ethanol extracts of the leaves of M. oleifera had the potential to function as a natural treatment against Z. arugamensis and P. damselae. Conclusion: These findings highlight the potential alternative antimicrobial drug for controlling diseases in aquaculture, offering a more environmentally friendly solution.