Identification of characteristic phenolic constituents in mousouchiku extract used as food additives

Abstract

Mousouchiku extract is prepared from the bamboo-sheath of Phyllostachys heterocycla MITF. (Poaceae), and is registered as a food manufacturing agent in the List of Existing Food Additives in Japan. This study describes the chromatographic evaluation of characteristic components of this extract to obtain the chemical data needed for standardized specifications. We isolated 12 known compounds from this extract: 5-hydroxymethyl-2-furfural, 4-hydroxybenzoic acid, trans-p-coumaric acid, trans-ferulic acid, N,N-diferuloylputrescine, 4-hydroxypropiophenone, β-arbutin, tachioside, isotachioside, 3,4-dihydroxy-propiophenone 3-O-glucoside, koaburaside, and (+)-lyoniresinol 9-O-glucoside. Moreover, a new propiophenone glycoside, propiophenone 4-O-(6-β-D-xylosyl)-β-D-glucoside (propiophenone 4-O-primeveroside), was isolated. The structure of each isolated compound was elucidated based on NMR and MS data or direct HPLC comparisons with authentic samples. Among the isolates, (+)-lyoniresinol 9-O-glucoside was found to be the major ingredients of the extract as observed using HPLC analysis. However, 2,6-dimethoxy-1,4-benzoquinone, which is considered the main constituent of mousouchiku extract, was only detected as a trace constituent and not isolated in this study.