In Vitro Assessment of Antimicrobial Potential of Ethanolic and Aqueous Extract of Against Some Highly Resistant Pathogens

Objective: To find out the antibacterial potential of ethanolic and aqueous roots extract of Phlomis umbrosa L. against both Gram positive and Gram negative isolates Methodology: Disk diffusion method according to Clinical Laboratory and Standards Institute (CLSI) standard was used to examine the in vitro antibacterial activity of P. umbrosa extract while minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using broth dilution technique. Miles and Misra technique was also utilized to count the number of colonies CFU/mL of bacteria at different concentrations of extract. Results: All the studied strains showed a diverse range of vulnerability against both ethanolic and aqueous plant extract. Among all tested isolates, ethanolic extract of P. umbrosa showed highly significant activity against Gram positive isolates i.e. S. aureus (20.1 mm) and B. subtilis (22.9 mm) with least MIC (12.5 mg/mL) and MBC (12.5 mg/mL) as compared to Gram negative isolates. A progressive decline in bacterial colonies (CFU/mL) was observed in Miles and Misra technique. One way ANOVA followed by postHoc Tukey test showed the significant differences in antimicrobial activities of plant extract with two tested antibiotics i.e. Amoxicillin and Erythromycin (10 µg/disc) as positive control at p-value of 0.05. The antimicrobial activity of this plant exhibit may be due to the presence of such chemical constituents namely monoterpenoids and sesquiterpenoids compounds. Conclusion: It is concluded that roots ethanolic extract of P. umbrosa has a promising antibacterial potential so it can also be used as an alternative medicine to treat different infections for reducing bacterial resistance and side effects associated with antibiotics.