Identification of Natural Oak Lactone Precursors in Extracts of American and French Oak Woods by Liquid Chromatography-Tandem Mass Spectrometry

摘要

A method for the screening of potential natural oak lactone precursors in oak wood extracts using LC-MS/MS combined with information-dependent acquisition was developed. The method was applied to extracts of American and French oak woods. As a result, cis-3-methyl-4-galloyloxyoctanoic acid (ring-opened cis-oak lactone gallate), (3S.4S)- and (3S,4R)-3-methyl-4-O-beta-D-glucopyranosyloctanoic acid (ring-opened cis- and trans-oak lactone glucoside), and (3S,4S)-3-methyl-4-O-(6'-Ogalloyl)-beta-D-glucopyranosyloctanoic acid (ring-opened cis-oak lactone galloylglucoside) were identified as natural oak lactone precursors in the extracts by comparison with the respective synthetic-reference compounds. In addition, the ring-opened oak lactone rutinoside was tentatively identified in the extracts. Three apparent isomers of the ring-opened cis-oak lactone galloylglucoside were also observed.