antibacterial effects of aqueous and alcoholic extract from Spinacia Oleracea L (varieties Mashhad) on bacterial indicators

products drived from Plants have been used for medicinal purpose for centuries because of antimicrobial activity. Using preservatives and anti-microbial material is one way of controlling pathogen bacteria in food stuff. Developing anti-microbial drugs is one of the most important advance in the treatment. Due to their natural origin, herbal extracts are more compatible with body organism than antibiotics and their side effects are very scarce. Spinach is considered as a source of new plant. Botanical analysis of Spinach indicated important active components on its extract. These studies have proven that the extract of Spinach leave maybe used as an anti-oxidation and anti-microbial agent to deal with free radicals and microbial pollutions.The objective of this study was to evaluate the antibacterial effect of aqueous and alcoholic extracts of Spinach (varieties Mashhad) on pathogenic bacteria Staphylococcus aureus ATCC25923, Escherichia coli ATCC2592 and, Listeria innocua ATCC33090.
The susceptibility testing of bacteria was performed by disc diffusion, MIC and MBC (using broth micro dilution method) methods. In disc diffusion method as a positive control Erythromycin, Gentamicin and chloramphenicol were used on Listeria innocua, Staphylococcus aureus and Escherichia coli .
According to disc diffusion method the most resistance was observed by gram positive bacteria (Listeria innocua, Staphylococcus aureus) whereas, the most sensitivity was observed by Escherichia coli. Also, the results of MIC showed that the rang of MIC for the aqueous extract of Spinach (varieties Mashhad) were between 46000 to 54680 PPM, 48000 to 54680 PPM and 28000 to 54680 PPM on Listeria innocua, Staphylococcus aureus and Escherichia coli respectively. Accordingly, this range for the alcoholic extract was equal (41580 to 10393 PPM), on Listeria innocua, Staphylococcus aureus and Escherichia coli. The both of aqueous and alcoholic extract of Spinach (varieties Mashhad) had antimicrobial properties.
alcoholic extract of Spinach (varieties Mashhad) had more antibacterial effect than aqueous extract on Escherichia coli . Also, the effect of its alcoholic extract on Escherichia coli could be compared with Erythromycin antibiotic at disc diffusion test on Listeria innocua. This means that antimicrobial effect of alcoholic extract on Escherichia coli can be as powerful as Erythromycin antibiotic on Listeria innocua. Finally, it can be concluded that high percent of flavonoids and terpenes compositions, unsaturated fatty acids and inorganic materials are probably the most important deterrent factors of spinach on gram-negative bacteria such as Escherichia coli. As a result Spinach extract can be used as a natural antibiotic in food industries and pharmaceutical.