Antibacterial Potential of Stevia rebaudiana Extract (Methanol and Ethanol) against Clinically Important Pathogens with Time-dependent Bactericidal Potency

Background: Antibiotic resistance is increasing worldwide, so alternative of commercial antibiotics should be in choice. S tevia rebaudiana (stevia) is a member of the Asteraceae family which contains potential antimicrobial agents to inhibit the growth of pathogenic microbes. Methods: The current study aims to evaluate the antimicrobial properties of S. rebaudiana against the multidrug-resistant bacteria. Time-kill assay was performed to observe the efficacy of the extracts against pathogenic microbes. The agar well-diffusion method was introduced to obtain the antibacterial activity of ethanol and methanol extract of stevia powder. The MIC was determined through 96-well plate technique. Results: The methanolic extract of stevia showed higher antibacterial activity as compared to ethanolic extract against all the bacterial strains. The highest zone of 18 mm was noticed against Gram-positive Staphylococcus aureus , while the lowest zone 15 and 11 mm was observed against Serratia marcescens and Salmonella typhimurium , respectively. The ethanolic extract produced the zone diameter within the range of 8–13 mm against the tested bacteria. Minimal inhibitory concentration (MIC) values of 1 mg/mL were recorded for all the bacterial strains, while minimum bactericidal concentration was 2 mg/mL. All the bacterial growth was significantly killed within 15 h accept S . typhimurium and Escherichia coli . Conclusion: The results of the present study indicate that the stevia leaf extracts have inhibitory efficacy against microorganisms, and further study will reveal the possibility of employing them in medicines for the treatment of infectious diseases caused by the test microorganisms.