Antioxidant activity and characterization of volatile constituents of beechwood creosote

Volatile constituents of beechwood creosote were determined using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The major volatile constituents of creosote were 2-methoxyphenol (guaiacol; 25.2%) 2-methoxy-4-methylphenol (4-methylguaiacol; 21.4%), 3-methylphenol (m-cresol; 8.3%) 4-methylphenol (p-cresol; 7.9%) 2-methylphenol (o-cresol; 4.6%) and phenol (2.8%). The antioxidant activity of creosote was evaluated by three different chemical assays. Beechwood creosote exhibited potent inhibitory effects on the formation of conjugated diene hydroperoxides (from methyl linoleate) at concentrations of 500, 750 and 1000 μg ml^-1. Creosote had a potent inhibitory effect on the oxidation of hexanal for 40 days at a level of 5 μg ml^-1 and also inhibited malonaldehyde (MA) formation from ethyl arachidonate by 92% at a level of 50 μg ml^-1. The antioxidative activity of creosote was comparable with that of the well-known antioxidants α-tocopherol and BHT in the hexanal assay. However, creosote displayed comparatively lower antioxidant activity in the other two assays.