C-Glycosylflavonoids in the leaves of gymnosperms

Abstract

The finding of vitexin derivatives as major flavonoids in needles of Larix /aricina, L. sibirica, L./eptolepis, L. decidua, L. gme/infi and, to a lesser extent, in those of L. occidentails instigated a literature survey on C-glycosides within the gymnosperms. Surprisingly, no reports had been made at the time of Alston's review in 1968, although many species had been investigated for flavonoids. Apart from the Larix compounds, C-glycosides had been reported in only two other species; a vitexin-like compound from Ephedra americana and vitexin and orientin as minor constituents in Dioon spinu/osum leaves. The question, therefore, arose whether the larch may be exceptional in this respect within the Pinaceae, or even among the Gymnospermae. Therefore, leaves of a 46 species of gymnosperms were subjected to a screening for C-glycoflavonoids occurring as major constituents.