HPLC determination of 4 hydroxybenzoic acids in extract of Ginkgo biloba leaves

Objective:To establish an HPLC method for the determination of the contents of 4 hydroxybenzoic acids(gallic acid,protocatechuic acid,p-hydroxybenzoic acid,m-hydroxybenzoic acid) in Ginkgo biloba leaf extract.Methods: The analyses were performed on a Thermo Syncronis C18 column(250 mm×4.6 mm,5 μm),the mobile phase was water containing 0.1% phosphoric acid-acetonitrile with gradient elution mode(0-8 min,5.7%A;8-9 min,5.7%A→6.7%A;9-45 min,6.7%A) at the flow rate of 1 mL·min-1;The detection was set at 260 nm(0-30 min) and 234 nm(30-45 nm),the column temperature was 30 ℃.Results: Good linearity(r=0.9998-0.9999) was observed in the standard curves of gallic acid,protocatechuic acid,p-hydroxybenzoic acid and m-hydroxybenzoic acid in the ranges of 30.53-457.9,391.2-5868,23.81-357.1 and 57.69-865.3 ng,respectively;The average recoveries(n=9) of the method were 99.8%,98.5%,100.2% and 99.6%,respectively.The limits of detection were 0.654,0.559,0.425 and 1.03 μg·g-1,respectively.Conclusion: The HPLC method can be used for the contents determination of 4 hydroxybenzoic acids in Ginkgo biloba leaf extract.The assay results of 4 hydroxybenzoic acids in Ginkgo biloba leaf extracts supplied by 7 manufacturers are very different,indicating that the content determination of hydroxybenzoic acids in Ginkgo biloba leaf extract should be controlled.