title: Identification and quantification of flavonoids of Mexican oregano (Lippia graveolens) by LC-DAD-ESI/MS analysis.
abstract: LC-DAD-ESI/MS was used to identify 23 flavonoids in the extract of Mexican oregano (Lippia graveolensH.B.K.), a spice and herb, used in the USA and Mexico. The identification of luteolin-7-O-glucoside, apigenin 7-O-glucoside, phloridzin, taxifolin, eriodictyol, scutellarein, luteolin, quercetin, naringenin, pinocembrin and galangin was confirmed by direct comparison with standards. Identification of 6-hydroxyluteolin, two 6-hydroxyluteolin 7-O-glycosides, three pentahydroxyflavanone hexosides, scutellarein 7-O-hexoside, 3-hydroxyphloretin hexoside, and three other flavones, was made by detailed analysis of their UV and mass spectral data. The identification of the flavonoid glycosides was further confirmed through detection of their aglycones following hydrolysis of the samples. The concentration of the identified flavonoids in three samples was also estimated. This is the first report of detection of over 20 flavonoids, including chalcones, in this plant material.
authors.affiliation: Food Composition Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, ARS-USDA, Beltsville, MD 20705, USA.
authors.forename: Long-Ze
authors.initials: LZ
authors.lastname: Lin
authors.affiliation: Food Composition Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, ARS-USDA, Beltsville, MD 20705, USA.
authors.forename: Sudarsan
authors.initials: S
authors.lastname: Mukhopadhyay
authors.affiliation: Food Composition Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, ARS-USDA, Beltsville, MD 20705, USA.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Robbins
authors.affiliation: Food Composition Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, ARS-USDA, Beltsville, MD 20705, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Harnly
keywords: Flavonoids; Identification; LC-DAD-ESI/MS; Lippia graveolens; Mexican oregano; Quantification