Isolation, identification and quantitation of hydroxycinnamic acid conjugates, potential platform chemicals, in the leaves and stems of Miscanthus x giganteus using LC-ESI-MS(n)

Type Article
Original languageEnglish
Pages (from-to)2376-2384
Number of pages9
JournalPhytochemistry
Volume72
Issue number18
Early online date06 Sep 2011
DOI
Publication statusPublished - Dec 2011
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Abstract

Miscanthus × giganteus is a source of platform chemicals and bioethanol through fermentation. Cinnamates in leaves and stems were analysed by LC–ESI-MSn. Free phenols were extracted and separated chromatographically. More than 20 hydroxycinnamates were identified by UV and LC–ESI-MSn. Comparative LC–MS studies on the leaf extract showed isomers of O-caffeoylquinic acid (3-CQA, 4-CQA and 5-CQA), O-feruloylquinic acid (3-FQA, 4-FQA and 5-FQA) and para-coumaroylquinic acid (3-pCoQA and 5-pCoQA). Excepting 3-pCoQA, all were also detected in stem. 5-CQA dominated in leaf; a mandelonitrile–caffeoylquinic acid dominated in stem. Three minor leaf components were distinguished by fragmentation patterns in a targetted MS2 experiment as dicaffeoylquinic acid isomers. Others (Mr 516) were tentatively identified as hexosylcaffeoyl-quinates. Three positional isomers of O-caffeoylshikimic acid were minor components. p-Hydroxybenzaldehyde was also a major component in stem. This is the first report of the hydroxycinnamic acid profile of leaves and stems of M. × giganteus.

Keywords

  • Miscanthus x giganteus leaf and stem tissue, hydroxycinnamic esters, UV, LC-ESI-MSn, high-value chemicals