Analysis of rare flavonoid C-glycosides in Celtis australis L. by micellar electrokinetic chromatography

This manuscript reports on the first analytical procedure for the determination of flavonoids in Celtis australis. The capillary electrophoretic separation of 8 compounds, most of them flavone C-glycosides, was possible using a borax buffer with pH 9.0, which contained 25mM SDS as detergent and 7.5% of n-butanol as organic modifier. Method validation revealed that the developed assay is repeatable (sigma(rel)or=0.9996) within the tested concentration range. The quantitative analysis of several C. australis samples showed that isovitexin is the most abundant representative (0.06-0.09%), at a rather uniform content of total flavonoids of approx. 0.3% in all specimens.