Chemical composition and in vitro antibacterial activity of essential oil from Eupatorium africanum Oliv. & Hiern

Abstract

A hydrodistilled oil from the aerial part of Eupatorium africanum Oliv. & Hiern collected from D.R. Congo was analyzed by GC and GC/MS. Thirty three compounds representing 97.34% of the oil were identified. The major components were b-eudesmol (49.1%), 10-epi-g-eudesmol (11.30%), a-humulene (8.9%), hedycaryol (8.9%), and elemol (5.2%). The antibacterial activity of the essential oil and its dominant constituent was evaluated against four bacteria strains (Staphyloccocus aureus ATCC 25952, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 9027, Proteus vulgaris ATCC 4635) using the micro-dilution method. The results indicate that the two samples are active against all tested microorganisms. The oil has a moderate activity against Staphylococcus aureus and Pseudomonas aeruginosa with a minimum inhibitory concentration (MIC) value of 125 µg/mL. The isolated major constituent (b-eudesmol) exhibits the highest activity against Staphylococcus aureus and Pseudomonas aeruginosa with a MIC value of 62.5 µg/mL. Both samples exhibited a MIC value of 250 μg/ml against Escherichia coli. and Proteus vulgaris.