identification and measurement of active ingredients of laurus nobilis leaf and antibacterial effects by mic, mbc and disk diffusion methods

Laurus nobilis l. from the lauraceae family is one of the medicinal plants with many active ingredients whose extract has good antioxidant, antibacterial, antifungal and anti-inflammatory properties and can be used as a natural antioxidant or alternative to antibiotics in the treatment of some diseases. in this study, laurus nobilis l. was collected from the north of iran, dried and extracted with ethanol by soxhlet apparatus, then poured on a watch glass for 48 hours to evaporate the solvent.the prepared dry samples were applied to disk diffusion test with concentrations of 100 mg.ml-1, 50 mg.ml-1, 25 mg.ml-1, 12.5 mg.ml-1, 6.25 mg.ml-1 and 3.125 mg.ml-1 in the culture medium containing bhi agar. also the tests of minimum bacteriocidal concenteration (mbc) and minimum inhibitory concenteration (mic) were carried with concentrations of 400 mg.ml-1, 200 mg.ml-1, 100 mg.ml-1, 50 mg.ml-1, 25 mg.ml-1, 12.5 mg.ml-1, 6.25 mg.ml-1, 3.125 mg.ml-1, 1.56 mg.ml-1 and 0/78 mg.ml-1 in broth culture medium containing bhi. the results were investigated after 24 hours of incubation. the amount of mic effect of ethanolic extract of laurus nobilis l. on staphylococcus epidermis was 0.78 mg.ml-1 and 6.25 mg.ml-1 was obtained for escherichia coli. also in 3 higher concentrations, lethal property was obsereved for mbc method. according to the results, ethanolic extract of laurus nobilis l. showed a better inhibitory and lethal effect on gram-positive bacteria staphylococcus epidermis in comparison with gram-negative bacteria escherichia coli. finally, the ethanolic extract of laurus nobilis l. can be used as raw material in the manufacture of cosmetic products due to its inhibitory and lethal properties of skin microorganisms.