Chemical Constituents and Antimicrobial Activity of the Leaves of Eucalyptus (Eucalyptus camaldulensis Dehnh.), An Endemic Plant from West Anatolia

Abstract

The extracts of methanol water, hexane and chloroform eucalyptus leaves (Eucalyptus camaldulensis Dehnh.) were screened in vitro for their antimicrobial activity against some pathogenic gram negative, gram positive bacteria and one yeast. Disk diffusion method was used for antimicrobial activity of extracts and the microwell dilution assay was used for the determination of minimal inhibitory concentration (MIC) of each extract. In addition, the composition of chloroform extratc was determined by means of GC/MS analysis. The methanol/water, hexane and chloroform exracts of E.camaldulensis leaf showed various antimicrobial activity 7-9mm, 8-11mm and 11-27 mm inhibition zone, respectively. The chloroform extracts was found to be the most effective antimnicrobial agent as compared to the other extracts. While the most sensitive bacteria was Bacillus cereus CCM 99 (27mm inhibition zone), the most resistant bacteria was Esherichia coli ATCC 35218. The methanol/water, hexane and chloroform extracts of E. camaldulensis leaf showed 1.25-5.0<mu g/ml, 0.625-5.0<mu g/ml and 0.039-0.625 mu g/ml MIC value, respectively. While the chloroform extract displayed the best activity (MIC 0.039 mu g/ml) against B.subtilis ATCC 6633 and B.cereus CCM 99 and C.alhicans ATCC 10239, it showed the least activity (MIC 0.625 mu g/ml) against E.coli ATCC 35218. The GC/MS analyses allowed 11 compounds to be determined; the main constituents of the Eucalyptus leaves extract were chloroform (68.5%), hexane(10.85%), ethylacetate (9.12%), ethanol (8.25%), gamma terpiene (0.78%), bromochloromethane (0.59%), 1,8 cineole (0.52 %). The data of this work indicate that extracts of eucalyptus leave from West Anatolia, especially the chloroform extracts, could be formed the basis of many applications including raw and processed food preservation, pharmaceuticals, alternative medicine, and natural therapies.