title: Identification of flavonoids in Hakmeitau beans (Vigna sinensis) by high-performance liquid chromatography-electrospray mass spectrometry (LC-ESI/MS).
abstract: Liquid chromatography coupled with electrospray mass spectrometry (LC-ESI/MS) with positive and negative ion detection was used for the identification of flavonoids in Hakmeitau beans, a black seed cultivar of cowpea (Vigna sinensis). Gradient elution with water and acetonitrile, both containing 2% formic acid, was employed in chromatographic separation. The peaks were identified by comparison of the retention times and the UV-vis spectroscopic and mass spectrometric data with authentic standards and/or literature data. The identified flavonoids included six anthocyanins (cyanidin 3-O-galactoside, cyanidin 3-O-glucoside, delphinidin 3-O-glucoside, malvidin 3-O-glucoside, peonidin 3-O-glucoside, and petunidin 3-O-glucoside) and four flavonol/flavonol glycosides (kaempferol 3-O-glucoside, quercetin, quercetin 3-O-glucoside, and quercetin 3-O-6' '-acetylglucoside). The tentatively identified flavonoids included two anthocyanins (malvidin 3-O-acetylglucoside and peonidin 3-O-malonylglucoside) and three flavonol glycosides (myricetin-3-O-glucoside, quercetin 7-O-glucoside, and quercetin-3-O-diglucoside). These flavonoids are present in seed coats, and the contents of anthocyanins and flavonol glycosides were 20.7 and 2.0 mg/g, respectively.
authors.affiliation: Laboratory for Food Protein Production, Department of Biology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, People's Republic of China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Chang
authors.forename: Yum-Shing
authors.initials: YS
authors.lastname: Wong
mesh_terms: D000872:Anthocyanins / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D007887:Fabaceae / Q000737:chemistry*; D005419:Flavonoids / Q000032:analysis*; D044948:Flavonols / Q000032:analysis; D006027:Glycosides / Q000032:analysis; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D000872:Anthocyanins; D005419:Flavonoids; D044948:Flavonols; D006027:Glycosides