Development of a sensitive and rapid HPLC method for quantitative measurement of ginkgolic acid in dietary supplementarys

Dietary supplements containing extracts of Ginkgo biloba are one of the most widely used supplements. These products are used for their purported benefit to improve cognitive functions, blood circulation and in management of neurodegenerative conditions. The beneficial effects of extracts are primarily attributed to flavonoids and triterpene lactones. Ginkgolic acids, a group of structurally-related alkyl phenols, have been shown to have some negative health effects. The European Union currently limits the amount of ginkgolic acid in supplements to a level of 5 parts-per-million (ppm) or less. Recently, the National Toxicology Program reported that G. biloba extracts caused cancers of thyroid and liver in rats and mice models. In the light of this report, we intend to measure ginkgolic acids content of Ginkgo dietary supplements in US market.

An HPLC-UV method using a biphenyl column was developed for the separation of three forms of ginkgolic acids (13:0, 15:1, 17:1). The samples were extracted by the QuEChERS method, in which the ginkgolic acids were partitioned in the acetonitrile layer, followed by HPLC-UV analysis. The developed method was validated for linearity, repeatability, accuracy, limits of detection, limits of quantitation and spiked recovery. The method successfully quantified total ginkgolic acid amounts below 5 ppm levels. Quantitative data on the ginkgolic acid content in the dietary supplements will be presented.