ABSTRACT
Brassica juncea, often referred to as brown mustard or Indian mustard, possesses considerable medicinal significance owing to its wide range of bioactive chemicals and potential healthpromoting properties, particularly in the regions of Asia and Africa. The primary objective of this study was to assess the antibiogram of the methanolic extracts of Brassica juncea against Escherichia coli, Pseudomonas aeruginosa, Klebsiella spp, and Staphylococcus aureus. These bacterial isolates were obtained from urine samples collected from undergraduate students attending the University of Benin in Edo State. A total of 200 samples were randomly obtained and subjected to analysis in order to determine the presence of uropathogens, using established microbiological techniques. The methanolic extracts of the seeds were obtained through Soxhlet extraction technique. The samples were subsequently subjected to analysis for their antibacterial properties using the agar well diffusion technique. Among the 200 participants included in the study, it was observed that 121 individuals, accounting for 60.5% of the sample, tested positive for bacterial contamination; with 212 microorganisms isolated, indicating the presence of one or more bacterial species, while 39.5% (79) showed no significant growth. The predominant microorganism identified was Escherichia coli (40.6%) followed by Staphylococcus aureus (25.0%), Pseudomonas aeruginosa (21.2%) and Klebsiella spp. (13.2%). The antimicrobial activity of the extracts showed a higher efficacy at a concentration of 400mg/dl against all tested isolates, and as the dilution of the extracts increased, the degree of antimicrobial activity diminished. The reported Minimum Inhibitory Concentrations (MICs) of the seed extract were 6.25mg/dl for Staphylococcus aureus, 6.25mg/dl for Klebsiella spp, and 12.5mg/dl for Escherichia coli. The MIC for Pseudomonas aeruginosa was 3.125mg/dl. The synergism of the methanolic seed extract alongside Imipenem, Ciprofloxacin, and Levofloxacin demonstrated a noteworthy amplification in the antibacterial efficacy against Staphylococcus aureus, resulting in a larger zone of inhibition. Similar results were observed when Nalidixic Acid, Nitrofurantoin, and Levofloxacin were combined and tested against Klebsiella spp and Escherichia coli. However, the combined effect of the conventional antibiotics and the methanolic extracts exhibited little antibacterial efficacy against Pseudomonas aeruginosa. These findings serve to validate the antimicrobial potential of Brassica juncea on uropathogens.
