Extraction and Characterization of Hydrophilic Extractives of Hardwood Knots

In this study، hydrophilic extractives of Beech، maple، alder and hornbeam knots were isolated and characterized by means of gas chromatography - mass spectrometry (GC / MS). Also، antioxidant activity of the extracts extractives was studied. Hydrophilic compounds of the extractives were isolated by soaking the wood flour in the solvent. Isolation was made using a hexane pretreatment for removing the lipophilic moieties followed by an ethanol - water (v/v1:9) treatment. Results showed that the type and amount of extractives in different species is different and maximum yield of 33. 4 % was obtained for hornbeam knots. TLC analysis showed that the compounds in ethanol extract were separated in only two distinct bands. Comparative evaluation of the total phenolics by Folin- ciocalteu and GC/MS analysis showed that extraction by simple soaking can accurately represent the amount of phenolic compounds in the extracts. Studying the antioxidant properties of extracts using DPPH radical scavenging and Iron (II) chelating capacity showed that the antioxidant activity is dependent to the amount and type of phenolics in the extracts.