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

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. 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. 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 . 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. 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 . These findings highlight the potential alternative antimicrobial drug for controlling diseases in aquaculture, offering a more environmentally friendly solution.