Antimicrobial activity of globulol isolated from the fruits of Eucalyptus globulus Labill

An antimicrobial sesquiterpene was separated by bioassay-guided isolation from the petroleum ether fraction of the ethanol crude extract of Eucalyptus globulus Labill (Myrtaceae) fruits, and was identified as globulol by physicochemical properties and spectroscopic analysis. Mycelial growth method revealed that the median effective inhibitory concentration (IC50) values of globulol on Alternaria solani, Fusarium oxysporum f.sp. niverum, F. graminearum, Rhizoctonia solani and Venturia pirina were 47.1 mu g mL(-1), 114.3 mu g mL(-1), 53.4 mu g mL(-1), 56.9 mu g mL(-1), 32.1 mu g mL(-1) and 21.8 mu g mL(-1), respectively. MTT-colorimetric assay revealed that IC50 values of globulol on Xanthomonas vesicatoria and Bacillus subtilis were 158.0 mu g mL(-1) and 737.2 mu g mL(-1), respectively. The results indicated that globulol could be a main antimicrobial compound in the ethanol crude extract of E. globulus fruits.