Secondary Metabolites with Anti-complementary Activity from the Stem Barks of Juglans mandshurica Maxim

Juglans mandshurica is a fast growing hard species, which is a tree in family of Juglandaceae and has a wide distribution in China, Korea and eastern Russia. Plant materials from J. mandshurica have extensively been used in folk medicines to prevent or cure gastric, esophageal, lung and cardiac cancer. As one chain of our searching for anticomplementary agents from natural sources, two epimeric ellagitannins, [2,3-O-4,4',5,5',6,6',-hexahydroxydiphenoyl (HHDP))-(${\alpha},{\beta}$)-D-glucose] (I) and pedunculagin (II) were purified from 70% acetone extracts of the stem barks of J. mandshurica by Thin Layer Chromatography and Sephadex LH-20 column chromatography approaches. The chemical structures of the isolated compounds were characterized by MS, NMR, and a careful comparation with published literatures. The epimeric ellagitannins I and II exhibited inhibitory properties against a classical pathway of complementary system with 50 % inhibitory concentrations ($IC_{50}$) values of 65.3 and $47.7{\mu}M$, respectively, comparing with riliroside ($IC_{50}=104{\mu}M$) and rosmarinic acid ($IC_{50}=182{\mu}M$), which were used as positive controls. Thus, the work indicated both the two secondary metabolites possess excellent inhibitory activity and might be developed as potential anticomplementary chemicals.