BIPIN KANZARIYA, AMITA MISHRA, S.K. PATEL² AND PRITI MAHLA
Abstract
The increasing prevalence of antimicrobial resistance (AMR) has intensified the search for sustainable and natural alternatives to conventional antibiotics. In the present study, we evaluated the antimicrobial potential and storage stability of lyophilized and methanolic cow dung extracts derived from organically raised Gir cows. Extracts were prepared under sterile and standardized conditions and assessed against four clinically significant ATCC reference strains: Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, and Salmonella typhimurium ATCC 14028. Antimicrobial activity was determined using agar well diffusion and broth microdilution assays in accordance with the Clinical and Laboratory Standards Institute guidelines. Phytochemical analysis revealed the presence of phenolics, flavonoids, and alkaloids in both extracts, with higher phenolic content observed in the cow dung extract (78.9 ± 5.1 mg GAE/g) than in the cow urine extract (45.6 ± 3.2 mg GAE/g). Despite this, the cow urine extract demonstrated superior antimicrobial activity, producing larger zones of inhibition (12.2-16.0 mm) and lower minimum inhibitory concentration (MIC) values (0.25-0.50 mg/ml) than the cow dung extract (11.5-13.4 mm; 0.50-0.75 mg/ml). The greatest activity was observed against E. coli, with the cow urine extract showing a 50% lower MIC than the dung extract. Gentamicin controls confirmed the assay validity and exhibited substantially higher potency, as expected. Stability studies indicated that both extracts retained >90â95% of their initial antimicrobial activity after 12 weeks at -20 °C, with minimal loss (<10%). However, storage at room temperature (~25 °C) resulted in moderate activity reductions (15-25%) within four weeks, highlighting the importance of cold storage for bioactive preservation. Overall, our findings demonstrate that lyophilized cow urine extract exhibits stronger antimicrobial efficacy than methanolic cow dung extract against major gram-positive and gram-negative pathogens. These results support the potential application of bovine-derived bioactive extracts as eco-friendly antimicrobial agents and contribute to sustainable waste valorization strategies for combating antimicrobial resistance.