Evaluation of Antibacterial Effect of Cinnamomum verum, Zingiber officinale, Hibiscus sabdariffa, Berberis vulgaris and Mentha Pulegium plant Extracts on some of Gram- Positive and Gram-Negative Bacteria

Increasing use of antibiotics against infection caused by microorganisms has increased drug resistance. This has led to extensive research on plant compounds with antimicrobial properties and greater effectiveness as an alternative to antibiotics. The purpose of this study was to evaluate antibacterial activity the five Medicinal plant extracts CinnamomumVerum, Zingiber officinale, Hibiscus sabdariffa, Berberis vulgaris,  and Mentha pulegium against standard bacteria: Staphylococcus aureus, Staphylococcus saprophyticus, Entrococcous fecalis, Pseudomonas aeroginosa,Acintobacter bumani, Klebsiella pneumoniae, and Esherishia  coli.

The present experimental study was conducted in 2020 at Kurdistan University of Medical Sciences, Iran. The ethanol extract of the Cinnamomum verum, Zingiber officinale, Hibiscus sabdariffa, Berberis vulgaris and Mentha pulegium were prepared by maceration method.The antibacterial activity of the extracts was performed on several standard bacterial strains by agar well diffusion method after three replications and diameter of the zone of inhibition was measured and recorded. Then MIC (minimum inhibitory concentration) with Broth microdilution was determined. Mean growth zone diameter was analyzed by Duncanchr('39')s comparison test at the 5% level.

In the present study, the highest antibacterial effect was related to Berberis vulgaris and Zingiber officinale extracts on S. saprophyticus with growth inhibition drops of 25 and 23 mm, respectively (p <0.05). Hibiscus sabdariffa extract on S.saprophyticus and Mentha pulegium extract on E. coli had the highest antibacterial effect with a growth halo diameter of 16, 13 and 13 mm, respectively (p <0.05). The highest antibacterial effect of cinnamon was on Staphylococcus aureus with a diameter of 19 mm. The lowest growth inhibitory concentration was observed for Berberis vulgaris and Zingiber officinalis extracts against S. saprophyticus with 3.1 mg / ml and lower than other types of extracts. P. aeruginosa showed resistance to most plant extracts (p<0.05).

The results of the present study revealed that the plant extracts specially Berberis vulgaris had effective antibacterial activity on most of the bacterial strains. In order to show the optimal antibacterial effect of the studied extracts, it is suggested to study on the animal models and determine their clinical effects.