Antimicrobial effect aqueous and ethanolic extract of Avicennia marina on microorganisms the infection and intoxication in vitro

Avicennia marina (Forssk.) Vierh is the most current species among these plants in Iranian mangrove forest. Regarding to the biologically active compounds and traditional use of the leaves for treatment of smallpox and wounds, it seems that this plant has significant anti-microbial effects. The aim of this study was to evaluate antimicrobial effects of various concentrations of mangrove leaves on Staphylococcus aureus, Escherichia coli and Penicillium digitatum. In this study, antimicrobial effect of extracts evaluated by two methods, “Collins method” and “disk agar diffusion method” on Staphylococcus aureus PTCC 1337, Escherichia coli PTCC 1330 and Penicillium digitatum PTCC 5251 microorganisms. The minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC) and minimum bactericidal concentration (MBC) for both species were determined by using a dilution method. The results showed that in "disk agar diffusion test ", extract with 20, 40, 60 and 80 percent concentration has inhibition effect on Staphylococcus aureus and Penicillium digitatum, but only 60 and 80 percent of alcoholic extract has prevention effect on Escherichia coli. There was inhibition effect for watery extract in 60 and 80 percent on Staphylococcus aureus and 80 percent on Penicillium digitatum. MFC for mangrove alcoholic leaves was 16 mg/ml for Penicillium, however, MFC of aqueous extracts was 64 mg/ml for Penicillium. Alcoholic extract was more effective than watery extract as antimicrobial against on Staphylococcus aureus, Escherichia coli and Penicillium digitatum. The mangrove leaves extract, in vitro showed significant antimicrobial effect on studied microorganisms.