The Extraction of Naphthoquinone and Tetralones from Walnut Green Husks Using Subcritical Water and Supercritical Carbon Dioxide Methods: Comparison of the Antioxidant Activities of the Extracts

The green husks of the walnut (Juglans regia L.), which is of industrial importance and cultivated in our country, were collected from the Hakkari province and extracted using subcritical water and supercritical carbon dioxide methods. The effects of different extraction methods under various temperature and pressure conditions on the chemical composition of the husks was examined using the obtained GC-MS (Gas Chromatography-Mass Spectrometry) analysis results.The content of the walnut husks extracts was classified into tetralones, hydrocarbons, fatty acid esters and naphthoquinones. Furthermore, the antioxidant activities of the extracts were analyzed using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method. The amount of tetralones in the extracts directly affected the DPPH antioxidant activity results.