Spectral characters of a complex flavonoid isolated from the farinose exudate of Pityrogramma calomelanos

Abstract A complex flavonoid, previously referred to as ‘D-2/b’, was isolated from the farinose frond exudate of the fern Pityrogramma calomelanos in a pure state. Its earlier suggested structure, 8-(2-carboxyl-1-phenylethyl)-5,7-dihydroxyflavone δ-lactone, is confirmed by complete NMR analysis.