Antimicrobial Activity of Rubia florida ethanolic Extract on Pathogenic Bacteria “in vitro”

Rubia florida have various medicinal effects such as anti-cancer, antimicrobial and antioxidant and antiseptic properties. Therefore, the aim of this study was to evaluate the antibacterial effect of ethanolic extract of R. florida against pathogenic bacteria Enterobacter aerogenes, Escherichia coli, Streptococcus pyogenes and Staphylococcus epidermidis.

Antimicrobial methods of disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration were used to evaluate the antibacterial effect of ethanolic extract of R. florida against Enterobacter aerogenes, Escherichia coli, Streptococcus pyogenes and Staphylococcus epidermidis.

The antibacterial effect of the extract was concentration dependent and increasing its concentration increased the diameter of the growth inhibition zone. According to the results of disk diffusion agar and well diffusion agar tests, Staphylococcus epidermidis was the most sensitive bacterial strain to the extract. The diameter of growth inhibition zone in the presence of 40 mg/ml of extract for this strain in disk diffusion agar and well diffusion agar was 14.60 and 15.80 mm, respectively. In addition, the minimum inhibitory and bactericidal concentrations for Gram-positive bacteria were lower than for Gram-negative bacteria.

Ethanolic extract of R. florida can be used as a natural antimicrobial agent to prevent the growth of pathogenic microorganisms.