A simple HPLC-UV method for the assay of ginkgolic acids in Ginkgo biloba extracts

Extracts from the leaves of Ginkgo biloba are among the most widely used phytotherapeutics. Some alkylphenols (ginkgolic acids, cardanols and cardols) have been described as potentially hazardous constituents in Ginkgo extracts. Accordingly, a requirement for a maximum concentration of ginkgolic acids has been proposed in the UE and US pharmacopoeias Ginkgo monographs establishing a limit value of 5 ppm. A novel HPLC-UV method, developed by the use of HPLC-APCI-MS HPLC-DAD techniques and allowing the identification of ginkgolic acids and related phenols, is described. The new analytical method, not requiring enrichment procedures, can be used for the quantification of ginkgolic acids in Ginkgo extracts.