Investigation of flavonoid glycosides from Neolitsea sericea var. aurata via the general method and HPLC-SPE-NMR

Six flavonoid rhamnosides (1-2, 4-7) were separated from the water-soluble non-alkaloidal portion of the EtOH extract of the leaves of Neolitsea sericea var. aurata using various chromatographic techniques including Sephadex LH-20, centrifugal partition chromatography, and RP-18 Lobar. One additional compound (3) besides these six was identified by application of HPLC-SPE-NMR in a flavonoid rich fraction. The latter approach consumed only 1.5 mg of samples, theoretically equivalent to 0.2 g of dry leaves. This study demonstrates that HPLC-SPE-NMR has great advantage over the general methods on the aspects of manpower, research time, amounts of plant materials, and consumables in separation and characterization of natural products.