|AVULA, BHARATHI - University Of Mississippi|
|SAGI, SATYANARAYANARA - University Of Mississippi|
|GAFNER, STEFAN - Desiderio Finamore Veterinary Research Institute (FEPAGRO)|
|UPTON, ROY - American Herbal Pharmacop|
|WANG, YAN-HONG - University Of Mississippi|
|WANG, MEI - University Of Mississippi|
|KHAN, IKHLAS - University Of Mississippi|
Submitted to: Analytical and Bioanalytical Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/23/2015
Publication Date: 8/22/2015
Publication URL: http://handle.nal.usda.gov/10113/62577
Citation: Avula, B., Sagi, S.J., Gafner, S., Upton, R., Wang, Y., Wang, M., Khan, I.A. 2015. Identification of Ginkgo biloba supplements adulteration using high performance thin layer chromatography and ultra high performance liquid chromatography-diode array detector-quadrupole time of flight-mass spectometry. Analytical and Bioanalytical Chemistry. 407(25):7733-7746. doi: 10.1007/s00216-015-8938-1.
Interpretive Summary: Ginkgo biloba is one of the most widely sold herbal supplements and medicines in the world. A Ultra High Performance Liquid Chromatograpy (UHPLC) - Diode Array Detector (DAD) - Quadrupole Time of Flight-Mass Spectrometry (QToF-MS) and High Performance Thin Layer Chromatography (HPTLC) methods were developed for the quality screening of ginkgo samples. This study examined the similarity and dissimilarity of 25 commercially available G. biloba dietary supplements (GBP1-GBP25), 14 samples of G. biloba leaves and leaf extracts, 3 samples of S. japonicum fruits and 2 samples of S. japonicum flowers using UHPLC-DAD-QToF-MS in positive ion mode. A simple and fast HPTLC method was also developed for the chemical fingerprint analysis of flavonoids from ginkgo samples. Eleven out of twenty-five ginkgo retail products tested showed clear evidence of adulteration with S. japonicum fruits or flowers. Nine out of 25 supplements contained measurable amounts of quercetin, genistein, isorhamnetin and kaempferol. Both methods are useful in establishing the quality and authenticity of herbal products claiming to contain G. biloba.
Technical Abstract: Ginkgo biloba is one of the most widely sold herbal supplements and medicines in the world. Its popularity stems to have 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 profile 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 made therefrom do not contain genistein, and presence of which even in trace amounts, is suggestive of 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.