5,7,3′,4′5′-pentahydroxyflavanone in the bracts of helichrysum bracteatum

Abstract

Chromatographic investigations on Helichrysum bracteatum revealed the presence of three flavanones in the bracts. Two of them were the well known flavanones naringenin and erio- dictyol. The third flavanone was identified as the hitherto in nature unknown 5,7,3′,4′,5′- pentahydroxyflavanone. This was accomplished by chromatographic and spectrophotometric comparison with an authentic sample prepared from 3,4,5,2′,4′,6′-hexahydroxychalcone-2′- glucoside. Moreover, precursor experiments with suitable white flowering mutants of Matthiola incana and Antirrhinum majus also confirmed that the third compound was identical with 5,7,3′,4′,5′-pentahydroxyflavanone.