Potentials of walnut (Tetracarpidium conophorum Mull. Arg) leaf and onion (Allium cepa Linn) bulb extracts as antimicrobial agents for fish

Abstract

See, stats, and : https : / / www . researchgate . net / publication / 268485488 Potentials (Tetracarpidium conophorum . Arg) leaf (Allium cepa) bulb . . . Article DOI : 10 . 5897 / AJMR12 . 814 CITATIONS 4 READS 56 4 , including : Some : Wildlife Evaluation Bello . s Ondo 12 SEE Flora University 24 SEE Benjamin University 218 SEE All . The . The development of antibiotic - resistant pathogens due to the indiscriminate use of antibiotics has led to advocacy for the use of natural products in the treatment of fish diseases . The antimicrobial activity of methanolic and ethanolic extracts of walnut leaves and onion bulbs were evaluated against six pathogenic bacteria (Pseudomonas aeruginosa , Staphyloccocus aureus , Bacillus subtilis , Pseudomonas fluorescens , Escherichia coli , Samonella typhi) using the cup – plate method . Minimum Inhibitory Concentration (MIC) was determined using standard methods . Data were analysed using descriptive statistics . Onion bulbs and walnut leaves were also screened for secondary metabolites and this indicated the presence of saponins , tannin , alkaloids , cyanogenic glycosides and flavonoids ; while anthraquinones were not detected in both plants . The zone of inhibition varied with the bacteria and type of extract . The average diameter of inhibition zones was 10 ± 0 . 00 and 9 ± 0 . 02 mm for methanolic and ethanolic extracts of walnut leaves and onion bulbs , respectively . Staphylococcus aureus , B . subtilis and P . aeruginosa were most sensitive to the extracts . However , S . aureus was more sensitive to the extracts of walnut leaves and S . typhi was the least sensitive . Bacillus subtilis was more sensitive to the extracts of onion compared to E . coli which was the least sensitive . Minimum inhibitory concentration of walnut leaves and onion bulbs extracts on the bacteria tested were both 500 µg / ml . The results indicated that walnut leaves and onion bulbs had antibacterial activity on the tested organisms and showed their prospects for their use in the treatment of fish diseases .