Determination of ginkgolides and flavonols in ginkgo biloba products and NIST ginkgo reference standard by LC/UV/MS

The leaf extract of Ginkgo biloba has purported value for improving mental capacities in Alzheimer's patients. The unique components of GBE are the ginkgolides and bilobalides (terpene lactones) and a family of glycosylated flavols. Most clinical studies with Ginkgo biloba use either EGb 761®, or extracts that meet the same standard. (24% flavobnols by weight). This standard does not consider the relative concentration of any of these components. This study examined the flavonol and terpene lactone concentrations of seven commercially available Ginkgo biloba products and three standard reference materials (SRM 3246 Ginkgo biloba leaves, SRM 3247 Ginkgo biloba extract, and SRM 3248 Ginkgo biloba tablet) from the National Institute of Standards and Technology (NIST). Methanol‐water (1:1) extracts of Ginkgo biloba products and NIST SRMs were analyzed qualitatively and quantitatively using reversed‐phase chromatography with diode array and mass spectrometric detection. The concentrations of the flavonol glycosides were similar for the 3 NIST SRMs, but the flavonol content of the commercial Ginkgo biloba products varied dramatically. This study demonstrates the need to account for the concentration of individual components and not just total concentrations. This research was supported by the Agricultural Research Service at USDA and the Office of Dietary Supplements, NIH.