Chemical composition, antimicrobial and antioxidant properties of the volatile oil and methanol extract of Xenophyllum poposum.

The essential oil and methanol extract of northwestern Argentina medicinal plant Xenophyllum poposum, collected in Catamarca province, were investigated. GC and GC-MS analyses of the essential oil identified 56 compounds accounting for 92.9%. The main components of the oil were delta-cadinene (16.5%), 6-hydroxytremetone (14.7%), epi-alpha-cadinol (12.0%), alpha-cadinol (8.8%), gamma-cadinene (7.5%), 1-epi-cubenol (4.2%) and alpha-muurolene (3.0%). The essential oil exhibited antibacterial activities against five pathogenic strains as well as antifungal activities against two pathogenic fungi. The methanol extract showed antibacterial activity against two strains of Staphylococcus aureus and two pathogenic fungal strains. The main components isolated from the methanol extract were the antifungal 4-hydroxy-3-(isopenten-2-yl)-acetophenone, 6-hydroxytremetone, and tremetone. 6-Hydroxytremetone showed activity against all the fungal strains and one of the S. aureus strains assayed. Antioxidant and radical-scavenging properties of the methanol extract and essential oil were determined using the 2,2'-diphenyl-1-picrylhydrazyl assay and beta-carotene bleaching (BCB) test. The methanol extract and the essential oil showed, respectively, moderate and weak antioxidant activity when compared to butylated hydroxytoluene.