Isolation and structural elucidation of heartwood extractives of Juglans sigillata

Juglans sigillata is a deciduous tree in Juglandaceae that grows native in southwestern China. The extracts of J. sigillata are used extensively in folk medicines to treat or prevent various diseases. However, the individual components of J. sigillata heartwood are not known. In this work, the following substances have been isolated from the heartwood: a new trans-feruloyl isoflavone glycoside, namely 3'-methoxy-5'-hydroxy-isoflavone-7-O-(4''trans- feruloyl)-beta-D-glucoyranoside (I), a known isoflavone glucoside, i.e. 3'-methoxy-5'-hydroxy-isoflavone-7-O-beta-Dglucoyranoside (II), and two known flavonol glycosides: kaempferol-3-O-alpha-L-rhamnopyranoside (III) and myricetin3- O-alpha-L-rhamnopyranoside (IV). Chemical structures of extractives I similar to IV were elucidated mainly based on their spectroscopic [nuclear magnetic resonance (NMR), mass spectroscopy (MS), ultraviolet (UV) and infrared (IR)] and chemical analysis, as well as by comparison with literature data. Compound I was never isolated from any other plant, and it is described the first time in this work. Compound II was not found before in extracts of the genus Juglans, and the compounds III and IV are the first time described as components of J. sigillata extractives.