Evaluation of Antibacterial Activities of Aqueous Extract of Black Pepper (Piper nigrum L) Seeds against the Gram Positive Staphylococcus aureus and Gram-Negative Escherichia coli.

Abstract

Antibiotic resistance (AMR) represents a serious threat to public health and poses challenges in disease prevention and treatment despite various efforts to combat it. Evaluation of the in vitro antibacterial activity of aqueous extracts of black pepper seeds (Piper nigrum L.) against two infectious pathogens: Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The Department of Pharmacology and Therapeutics and the Department of Microbiology of Mymensingh Medical College conducted the study from Octy 2022 to June 2023. The antibacterial activity of Aqueous black pepper seed extract (ABPE) was evaluated at different doses using disk diffusion and broth dilution methods. The extract was prepared using 10.0% dimethyl sulfoxide (DMSO) and water as solvent. The commonly used antibiotic ciprofloxacin was used in the broth dilution method and the results were compared with those for aqueous extracts. To confirm a more precise range of antimicrobial susceptibility of the extracts, ABPE was used at seven different concentrations (100, 80, 60, 40, 20, 10 and 5 mg/mL). Selected concentrations were then used as needed. ABPE showed an inhibitory effect on the above bacteria at doses of 90 mg/ml and higher. The Minimum inhibitory concentration (MIC) values for Escherichia coli and Staphylococcus aureus were 85 and 90 mg/ml ABPE, respectively. The MIC of ciprofloxacin against Staphylococcus aureus and Escherichia coli was currently 1μg/ml. The MIC of ciprofloxacin was lowest for the organisms tested compared to the MIC of ABPE. This work clearly demonstrates the antibacterial sensitivity of Staphylococcus aureus and Escherichia coli to an aqueous extract of black pepper seeds.