Flavonol glycosides from waste broad bean aerial parts

The aerial parts of Vicia faba collected at seed maturation stage have no economic utility and are, therefore, discarded. However, these leaves and stems contain a considerable amount of flavonol glycosides. Two extraction procedures have been assayed: one using methanol-water as extraction solvent and another using alkaline water. The extraction yield (about 1 g of flavonoid/kg fresh plant material) was slightly higher when extracting with alkaline water, but this extraction hydrolyzes the acetyl derivatives, leaving almost exclusively the deacetylated compounds.