Abstract: Juglone(5-hydroxy-1,4-naphthaoquinone) is one of the active substances that was extracted from Juglans mandshurica Maxim. Juglone product was obtained from bark of J. mandshurica by ultrasonic extraction and vacuum distillation, and the yield of product was 0.09%. The product was characterized by FT-IR, GC-MS and ¹H NMR. The result showed all the characteristic absorption peaks of hydroxyl-naphthaoquinone in the FT-IR spectrum of the product. The constituents of the product were determined by GC-MS to be: 1,4-naphthaoquinone, 5-hydroxy-1,4-naphthaoquinone and 7-methoxy-1-tetralone, and the content of juglone in the product was 96.42%. The structure of juglone in the product was confirmed by ¹H NMR. This study offered a simple and effective method to get high purity juglone from bark of J. mandshurica.

Key words: juglone, bark of Juglans mandshurica Maxim., extraction, vacuum distillation