Flavonol Glycosides from the Seed Coat of a New Manteca-Type Dry Bean (Phaseolus vulgaris L.)

Abstract

Two flavonol glycosides were isolated from the methanol extracts of "Prim", a variety of Phaseolus vulgaris L. (Manteca-type), with a yellow seed coat color. High-performance liquid chromatography was used to isolate and identify compound 1, kaempferol (3,4,5,4′-tetrahydroxyflavone)-3-O-β-D-glucopyranoside, and compound 2, kaempferol 3-O-β-D-glucopyranoside-(2→1)-O-β-D-xylopyranoside. Concentrations of these compounds were 49.9 ± 0.78 mg/100 g and 58.5 ± 1.67 mg/100 g of fresh whole bean weight, respectively. These two flavonols were the only flavonoids found in Prim and our data indicate that they are responsible for imparting the yellow color to the seed coat. We were not able to indicate the biochemical effects of the eight genes responsible for seed coat color, but we show that G is probably not responsible for producing a flavonol 3,5-diglycoside as has been hypothesized in the literature. No proanthocyanidins (condensed tannins) were found in Prim dry bean seed coat.