Antioxidant Properties Of Compounds From Wood Vinegar

Wood vinegar?WV?,a condensed liquid,is obtained by clarifying the liquid product of smoke produced during wood carbonization.Wood vinegar is rich in organic compounds,such as various kinds of phenols,alcohols,fatty acids,ketones and so on.Based on its complex composition,wood vinegar is a kind of important green natural resources.Wood vinegar is widely used in agriculture,forestry,food,medicine,health care and other industries.In the present study,phenols were abtained from wood vinegar which occurs as a raw material in Northwest China by pH gradient extraction and the activity-guided isolation methods.The chemical compositions of the wood vinegar were analyzed by GC-MS.The dichloromethane was chosen to extract organic compounds from wood vinegar.The phenols were extracted with pH gradient extraction,and then the total phenolic content of the wood vinegar was estimated by a colorimetric assay.Seven phenols were isolated from the major antioxidant ingredient?T1?by using a sequence of chromatographic methods,including silica gel column chromatography,ODS column chromatography,and HPLC.The structures of compounds were identified as 1,2-Benzenediol?I₁?,1,4-Benzenediol?I₂?,3-methyl-1,2-Benzenediol?I₃?,4-methyl-1,2–Benzenediol?I₄?,3-methoxy-1,2-Benzenediol?I₅?,and2,6-dimethoxy-Phenol?I₆?,2,6-dimethoxy-4-methyl-Phenol?I₇?under NMR spectroscopic analyses.Then,the antioxidant activities of the compounds?I₁-I₇?were evaluated with DPPH,ABTS and FRAP assays compared with citric acid and ascorbic acid.In the DPPH assay,compounds I₁,I₂,I₄,I₇ showed a higher antioxidant activity than the positive control?ascorbic acid?.In the ABTS assay,it was clear that compounds I₂,I₆,I₇ showed more potent antioxidant activity,comparable with that of the positive control.The reduction capacity of compound I₅ at a concentration of 60?g/mL was 3190.81mg?AA?/g,the highest of all the compounds,followed by compounds I₆,I₂.The study can provide evidences for the development of food additives and preserves from wood vinegar.