The autoclave extraction of Hungarian oak (Quercus frainetto Ten.) wood gave 5.3% extractives. The chloroform soluble fraction obtained from the extracts of Q. frainetto allows to identify sesamin. The insoluble fraction contains mainly ribose and mannose. Water extraction in autoclave of thermo-treated Q. frainetto wood gave a lower amount of extractives (3.31%). The main product of the insoluble fraction was, on the basis of its mass spectrum, the monoacetyl derivative of gallic acid.
Keywords: Quercus frainetto; extractives; thermo-treated wood.