Antibacterial ِِActivity of Ethanol and Aqueous Extracts of Some Perennial Plants Against three Gram Negative Pathogenic Bacteria from Koya city – Kurdistan Region - Northern Iraq

Abstract

The aim of this investigation was to determine whether both ethanol and aqueous extracts of different parts of three Perennial plants (Dodonaea viscosa, Eucalyptus sp. and Pinus sp.) could provide the biological activity to inhibit the growth of three gram negative pathogenic bacteria include: Eschericia coli, Pseudomonas aeruginosa and Salmonella typhi. 20 grams of the plant parts powder were extracted with 200 ml of ethanol and 40 grams were extracted with 160 ml of distilled water. MIC was estimated for ethanol and aqueous. Antibacterial activity assay of the ethanol and aqueous extracts was carried out disk diffusion method. Pure colonies of test bacteria were transferred to nutrient broth and incubated overnight at 37C˚ and turbidity of prepared inoculums were adjusted equal to that 106 CFU/ml (standardized by 0.5 McFarland standards) and 100μl of inoculum was spread on Muller-Hinton agar medium by using a sterile glass spreader. For control, discs were impregnated with sterile water or absolute alcohol (control negative) and also standard antibiotic discs (ciprofloxacin 10μg/disc, Ampicillin 10μg/disc and cloxacillin 10μg/disc, Tobramycin 10μg/disc) as a control. Interestingly in our study we have observed promising antimicrobial activity against studied bacteria. It is worth mentioning that most of the results of aqueous and ethanolic extracts were distinct because they cannot appearing in some large inhibition zone, but it was interesting because it was close to the positive control , where inhibition percentage arrived to more than 90%. Suggest both extracts of D.viscosa shoots against P. aeruginosa, Eucalyptus sp. leaves against E.coli and S. typhi , ethanolic extract of pine cone against P. aeruginosa and aqueous extract of pine leaves against E.coli , as a good antibacterial” .