Evaluation of Antibacterial activity of methanolic extract of Hippophae rhamnoides leaf on Enterobacter aerogenes, Pseudomonas aeruginosa, Streptococcus pyogenes, and Bacillus cereus

Infectious diseases caused by pathogenic bacterial strains are increasing in many countries, including Iran. Hippophae rhamnoides L. is an important source of natural antimicrobial agents. The aim of this study was to extract methanolic extract of H. rhamnoides leaf and to evaluate its antimicrobial activity against Enterobacter aerogenes, Pseudomonas aeruginosa, Streptococcus pyogenes, and Bacillus cereus.

In this study, methanolic extract of H. rhamnoides leaf was extracted by the maceration method and then its antibacterial effect against bacterial pathogens Enterobacter aerogenes, Pseudomonas aeruginosa, Streptococcus pyogenes, and Bacillus cereus was evaluated using disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration.

The results of disk/well diffusion agar tests showed that increasing the extract concentration from 5 to 35 mg/ml caused a significant increase in the diameter of the growth inhibition zone for all microbial strains. Pseudomonas aeruginosa were the most resistant strains and Streptococcus pyogenes was found to be the most sensitive strains to the extract. The minimum inhibitory concentration for Gram-positive bacteria (4 mg/ml) was lower than that for Gramnegative bacteria (16 mg/ml). Also, the minimum bactericidal concentration for Streptococcus pyogenes and Pseudomonas aeruginosa was 256 and 512 mg/ml, respectively.

The results of the antimicrobial activity of the methanolic extract of H. rhamnoides leaf showed that it is possible to use the extract for medicinal purposes and food preservation.