The antibacterial activity of Althaea officinalis L. methanolic extract against some nosocomial pathogens in vitro and in vivo

Abstract

Althaea officinalis (A. officinalis) has been traditionally used to treat various infections. However the data on its antibacterial activity are scarce. Our aim was to study the antibacterial characteristics of A. officinalis methanolic extract against standard strains of Klebsiella aerogenes (K. aerogenes), Streptococcus pneumoniae (S. pneumoniae), Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) by in vitro and in vivo studies. Total flavonoid content was determined using spectrophotometry. The minimum inhibitory and bactericidal concentrations (MICs and MBCs, respectively) of A. officinalis were determined against bacterial species using both broth dilution and agar diffusion assays. In vivo experiment was performed using BALB/c mice in a model of S. aureus and P. aeruginosa skin infections. MIC and MBC of the extract was 100 mg/mL and 200mg/mL respectively against S. aureus and 50 mg/mL and 100mg/L against other pathogens. Exposure of 100mg/mL and 200mg/mL of methanolic extract significantly decreased P. aeruginosa and S. aureus growth (p<0.0001). The total flavonoid content of the extract was 973.09 ± 16.14 mg/gr. A. officinalis methanolic extract exhibited observable antibacterial activity in vitro and in vivo. The flavonoids mostly participate in A. officinalis antibacterial traits.