title: Characterization of phenolic components in polar extracts of Eucalyptus globulus Labill. bark by high-performance liquid chromatography-mass spectrometry.
abstract: High-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS) and tandem mass spectrometry (MS(n)) were used to investigate the phenolic constituents in methanol, water, and methanol/water extracts of Eucalyptus globulus Labill. bark. Twenty-nine phenolic compounds were identified, 16 of them referenced for the first time as constituents of E. globulus bark, namely, quinic, dihydroxyphenylacetic, and caffeic acids, bis(hexahydroxydiphenoyl (HHDP))-glucose, galloyl-bis(HHDP)-glucose, galloyl-HHDP-glucose, isorhamentin-hexoside, quercetin-hexoside, methylellagic acid (EA)-pentose conjugate, myricetin-rhamnoside, isorhamnetin-rhamnoside, mearnsetin, phloridzin, mearnsetin-hexoside, luteolin, and a proanthocyanidin B-type dimer. Digalloylglucose was identified as the major compound in the methanol and methanol/water extracts, followed by isorhamnetin-rhamnoside in the methanol extract and by catechin in the methanol/water extract, whereas in the water extract catechin and galloyl- HHDP-glucose were identified as the predominant components. The methanol/water extract was shown be the most efficient to isolate phenolic compounds identified in E. globulus bark.
authors.affiliation: CICECO, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Sónia A O
authors.initials: SA
authors.lastname: Santos
authors.forename: Carmen S R
authors.initials: CS
authors.lastname: Freire
authors.forename: M Rosário M
authors.initials: MR
authors.lastname: Domingues
authors.forename: Armando J D
authors.initials: AJ
authors.lastname: Silvestre
authors.forename: Carlos
authors.initials: C
authors.lastname: Pascoal Neto
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005052:Eucalyptus; D005419:Flavonoids / Q000032:analysis; D013058:Mass Spectrometry; D000432:Methanol; D010636:Phenols / Q000032:analysis*; D024301:Plant Bark / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry*; D014867:Water
chemical_list: D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D014867:Water; D000432:Methanol