HPLC-DAD, HPLC-MS and NMR characterization of flavonoid content in three Italian bean (Phaseolus vulgaris L.) ecotypes

Methanol extracts of seeds from 23 accessions of 3 Phaseolus vulgaris ecotypes (‘‘Sarconi’’, ‘‘Lamon’’, ‘‘Zolfino del Pratomagno’’), grown in different Italian regions (Basilicata, Veneto, Tuscany) were analyzed for their flavonoid content by HPLC-DAD, HPLC-MS and NMR . Flavonoid glycosides were found in the seed coat from ten accessions of the ‘‘Zolfino’’ ecotype and in one accession of the ‘‘Sarconi’’ ecotype. From highest to lowest concentration these compounds were kaempferol 3-O-glucoside (compound 2), kaempferol 3-O-xylosylglucoside (compound 1) and a not completely identified kaempferol monoglucoside (compound 3). Total flavonol content varied from 0.19 to 0.84 g/kg of seed fresh weight. Obtained results evidenced that some Italian bean ecotypes may be an important source of functional compounds as kaempferol glycosides.