title: Substitution pattern elucidation of hydroxypropyl Pinus pinaster (Ait.) bark polyflavonoid derivatives by ESI(-)-MS/MS.
abstract: The structure of condensed tannins (CTs) from Pinus pinaster bark extract and their hydroxypropylated derivatives with four degrees of substitution (DS 1, 2, 3 and 4) has been characterized for the first time using negative-ion mode electrospray ionization tandem mass spectrometry (ESI(-)-MS/MS). The results showed that P. pinaster bark CTs possess structural homogeneity in terms of monomeric units (C(15), catechin). The oligomer sizes were detected to be dimers to heptamers. The derivatives showed typical phenyl-propyl ether mass fragmentation by substituent elimination (58 amu) and inherent C(15) flavonoid fissions. The relative abundance of the product ions revealed a preferential triple, tetra-/penta- and octa- hydroxypropylation substitution pattern in the monomer, dimer and trimer derivatives, respectively. A defined order of -OH reactivity towards propylene oxide was established by means of multistage experiments (A-ring ≥ B-ring > C-ring). A high structural heterogeneity of the modified oligomers was detected.
authors.affiliation: Freiburger Materialforschungszentrum-FMF, Albert-Ludwigs University of Freiburg, D-79104, Freiburg, Germany; Chair of Forest Biomaterials, University of Freiburg, D-79085, Freiburg, Germany.
authors.forename: Danny E
authors.initials: DE
authors.lastname: García Marrero
authors.forename: Wolfgang G
authors.initials: WG
authors.lastname: Glasser
authors.forename: Antonio
authors.initials: A
authors.lastname: Pizzi
authors.forename: Sebastian
authors.initials: S
authors.lastname: Paczkowski
authors.forename: Marie-Pierre G
authors.initials: MP
authors.lastname: Laborie
mesh_terms: D005419:Flavonoids / Q000032:analysis* / Q000737:chemistry; D008958:Models, Molecular; D028223:Pinus / Q000737:chemistry*; D024301:Plant Bark / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods; D013634:Tannins / Q000032:analysis* / Q000737:chemistry
chemical_list: D005419:Flavonoids; D010936:Plant Extracts; D013634:Tannins
keywords: condensed tannins; degradation of catechin; derivatization; hydroxypropylation; maritime pine bark; tandem mass spectrometry