High Performance Liquid Chromatographic Determination of Ginkgotoxin and Ginkgotoxin‐5′‐Glucoside inGinkgo BilobaSeeds

A method for simultaneous determination of ginkgotoxin (4′‐O‐methylpyridoxin), ginkgotoxin‐5′‐glucoside, and vitamin B6 compounds in Ginkgo biloba seeds, has been developed by using high performance liquid chromatography (HPLC) with fluorescent detection. Satisfactory separation was accomplished on a C18 reversed‐phase column by gradient elution with potassium phosphate containing sodium 1‐pentanesulfonate (pH 2.5)‐acetonitrile within 20 min. The linearity of the calibration curves for ginkgotoxin and ginkgotoxin‐5′‐glucoside ranged from 0.1 pmol to 10 pmol per injection, and the detection limit was 0.025 pmol (SN=5). Hot water extracts of raw, canned, and plastic packaged Ginkgo biloba seeds obtained in Japan were analyzed by using this method.