Ginkgo Biloba Supplements Adulteration Identification Using HPTLC And UHPLC-QTOF-MS

Abstract

Ginkgo biloba is widely sold herbal supplements in the world. Its popularity stems from a positive effect on memory and the circulatory system in clinical studies. As ginkgo popularity increased, non-proprietary extracts were introduced claiming to have similar phytochemical profiles as the original extracts. The standardized commercial extracts of G. biloba leaves used in ginkgo supplements contain not less than 6% sesquiterpene lactones and 24% flavone glycosides. While sesquiterpene lactones are unique constituents of ginkgo leaves, the flavonol glycosides are found in many other botanical extracts. Being a high value botanical, low quality ginkgo extracts may be subjected to adulteration with flavonoids to meet the requirement of 24% flavonol glycosides. Using ultra high performance liquid chromatography-mass spectrometry revealed that adulteration of Ginkgo leaf extracts in many of these products is common, the naturally flavonol glycoside-rich extract being spiked with pure flavonoids or extracts made from another flavonoid-rich material, such as the fruits/flowers of the Japanese sophora (Styphnolobium japonicum), which also contains the isoflavone genistein. Recently, genistein has been proposed as an analytical marker for the detection of adulteration of ginkgo extracts with S. japonicum. This study confirms that botanically authenticated G. biloba leaves and extracts do not contain genistein, and presence of which even in trace amounts, is suggestive of possible adulteration. In addition to the mass spectrometric approach, a high performance thin layer chromatography method was also developed as a fast and economic method for chemical fingerprint analysis of ginkgo samples.