Antioxidant property of aroma extract isolated from clove buds [Syzygium aromaticum (L.) Merr. et Perry]

Aroma extract from dried clove buds [Syzygium aromaticum (L.) Merr. et Perry] was obtained by using steam-distillation under mild conditions (55°C and 95 mm Hg). The antioxidant property of the aroma extract was evaluated in two different assays. The aroma extract isolated from clove buds inhibited the oxidation of hexanal for 30 days at a level of 50 μg/ml. Clove bud extract inhibited malonaldehyde formation from cod liver oil by 93% at the 160 μg/ml level. Twenty-two compounds were identified in the extracts of clove buds by gas chromatography and gas chromatography/mass spectrometry. The major aroma constituents of clove buds were eugenol (24.371 mg/g) and eugenyl acetate (2.354 mg/g). Eugenol, eugenyl acetate, and benzyl alcohol inhibited the oxidation of hexanal by 99, 99, and 82%, respectively, for a period of 30 days at 500 μg/ml. Eugenol, eugenyl acetate, and benzyl alcohol inhibited malonaldehyde formation from cod liver oil by 88, 79, and 63%, respectively, at 160 μg/ml. The antioxidant activity of clove bud extract and its major aroma components, eugenol and eugenyl acetate, were comparable to that of the natural antioxidant, α-tocopherol (vitamin E).