Characterization of flavonoid content in Italian common bean (Phaseolus vulgaris L.) ecotypes.

Common bean had been recognized since a long time for its protein content. Recently, a new interest has grown relative to its nutraceutical value, attributed to the presence of secondary metabolites, particularly of flavonoids. Seeds of three Italian common bean ecotypes (“Zolfino”, “Sarconi” and “Lamon”) and two commercial cultivars (“Verdone” and “Lingua di Fuoco”) were analyzed (HPLC separations) for their flavonoid content. Results showed that “Zolfino” and “Verdone” accessions contained conjugated forms of the flavonoid kaempferol in seed coat. The total flavonoid content varied from 0.19 to 0.84 g/kg fresh seed weight and was estimated to be 7-fold less than the concentration of flavonoids (isoflavones) detected in soybean seeds. As follow-up action, “Zolfino” and “Verdone” accessions were analyzed to identify and quantify flavonoids at the seedling level. For comparison, one soybean cultivar (“Pacific”) and the cultivar “Lingua di Fuoco” were also included in the protocol analysis. In all the three common bean genotypes, the same soybean isoflavones (daidzein, glycitein and genistein) were detected; in “Verdone” and “Zolfino” small amounts of kaempferol were also observed. Results highlighted the possibility of considering investigated common bean genotypes as a valuable and “Mediterranean” alternative to soybean to obtain plant-derived products with health benefits.