Optimized Kaempferitrin Isolation from Uncaria guianensis Leaves by Solid-Phase Extraction

A simple and low-cost solid-phase extraction methodology for isolating the bioactive flavonoid kaempferitrin from a defatted fraction of the Uncaria guianensis leaf ethanol extract was developed using the kaempferitrin retention behavior in reversed-phase-high-performance liquid chromatography as well as thin-layer chromatography coupled to ImageJ software (Bethesda, USA) for densitometric analyses. In addition, the method enabled the isolation of less-complex mixtures for the further separation of minor constituents. The target compound was successfully isolated from 1 to 5 mg of the fraction per 500 mg C18 cartridge using 6 mL of 15% acetonitrile at 60% relative recovery and 99% purity.