Chemical constituents of the seeds of Ammopiptanthus (Leguminosae) and their systematic and ecological significance

Eleven flavonoids including a new flavone glycoside, 7,3′-dihydroxy-4′-methoxyflavone-7-O-β-glucopyranoside, and a quinolizidine alkaloid, lupanine, were isolated from the seeds of two Ammopiptanthus (Leguminosae) species, Ammopiptanthus mongolicus and Ammopiptanthus nanus. 7,3′-Dihydroxy-4′-methoxyflavone and lupanine were the major constituents in the seeds of both species. The patterns of seed flavonoids presented a clear systematic relationship between the two species. The simple seed alkaloid composition was presumed to be responsible for the weak defense capability of the seeds to insect pests in both species.