Determination of rutin,quercetin,kaempferol,and isorhamnetin in extract of Ginkgo biloba leaves by HPLC with solid phase extraction

Objective To determine four flavonol components as markers,rutin,quercetin,kaempferol,and isorhamnetin for quality control of extract of Ginkgo biloba(EGb)by a validated high performance liquid chromatographic(HPLC)method with solid phase extraction.Methods The four flavonols of EGb were extracted with Waters Sep-Park-C18 solid-phase extraction column.Separation was achieved using a Kromasil C18 column(250 mm×4.6 mm,5 μm)at 40 ℃ with a step linear gradient using methanol∶0.1% formic acid at a flow rate of 1.0 mL/min,wavelength was 360 nm,sample amount was 20 μL.Results The limits of quantitation for rutin,quercetin,kaempferol,and isorhamnetin were 20,6,5,and 5 mg/mL,respectively.This method was linear over concentration ranges of 14—198,15—205,3—40 and 3—41 mg/L for rutin,quercetin,kaempferol,and isorhamnetin,respectively.The solid phase extraction recoveries for rutin,quercetin,kaempferol,and isorhamnetin were 93.7%—104.7%.The precision of intra-day and inter-day were less than 2% and 3% for all compounds,repectively.Conclusion The vali-dated method is simple,accurate,and able to provide the basis for the quality control of flavonols in EGb.