Abstract: The extracts from leaves of Juglans mandshurica Maxim. were obtained by common extracting method for studying its antifungal activities and analyzing the active components. The results showed that alcoholic extracts and the acetic ether part of alcoholic extracts (separated with acetic ether from alcoholic extracts) from leaves of J. mandshurica had antifungal activities toward Alternaria alternate Fr. and Sphaeropsis sapinea Fr.. MIC of the alcoholic extracts and the acetic ether part of alcoholic extract were both 3.12 g/L toward A. alternate, and both 6.25 g/L toward S. sapinea. The active components in the acetic ether part I and part II (separated with silica gel column chromatography) of alcoholic extracts from leaves of J. mandshurica were analyzed by GC-MS. The results showed that major active components of relatively high content in the acetic ether part of alcoholic extracts from leaves of J. mandshurica were 1,4-naphthalenedione, 5-hydroxy-(juglone), D-allose, 5,8-dihydroxy-1,4-naphthalenedione, 1,5-naphthalenediol, 2,3-dihydro-benzofuran, 7-methoxy-1-tetralone, 1-naphthalenol, 8-hydroxy-2-methoxy-1,4-naphthalenedione and 4-methyl-2,6-dihydroxyquinoline.

Key words: Juglans mandshurica Maxim. leaves, extracts, antifungal activities