Some flavonoid components of Carmichaelia (Papilionaceae) — a chemotaxonomic survey

Abstract

The flavonoid analysis of 31 species of Carmichaelia shows the presence of isoflavones, flavonol 3-O-glycosides, flavonol 7-O-g1ycosides, flavonol 3, 7-di-O-glycosides, and flavone C-glycosides. Acid hydrolysis of 3-O-g1ycosides has yielded three flavonol aglycones — quercetin, isorhamnetin, and kaempferol — which are common to nearly all species, with one aglycone being dominant in each of them. Distribution of the dominant flavonol aglycones, and of the naturally occurring flavone C-glycosides, is seldom related to taxonomic boundaries but is predominantly geographical. Flavonoid analysis, together with the absence of distinct intraspecific and interspecific characters in the current classification of Carmichaelia, suggests that many species are closely related to one another. This study indicates that the correlation between flavonoid chemistry and the present taxonomic treatment of Carmichaelia is inconsistent. The need for a revision of the taxonomy of Carmichaelia is indicated.

Keywords:

• Carmichaelia
• chemotaxonomy
• flavonoids
• flavonol glycosides
• flavonol aglycones
• Cglycosylflavonoids
• New Zealand
• Lord Howe Island