High-resolution gas chromatography/mas spectrometry method for characterization and quantitative analysis of ginkgolic acids in ginkgo biloba plants, extracts, and dietary supplements

Authors: WANG, MEI - University Of Mississippi; ZHAO, JIANPING - University Of Mississippi; AVULA, BHARATHI - University Of Mississippi; WANG, YAN-HONG - University Of Mississippi; AVONTO, CRISTINA - University Of Mississippi; CHITTIBOYINA, AMAR - University Of Mississippi; WYLIE, PHILIP - Agilent Technologies, Inc; PARCHER, JON - University Of Mississippi; KHAN, IKHLAS - University Of Mississippi

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2014
Publication Date: 11/10/2014
Publication URL: https://handle.nal.usda.gov/10113/62411
Citation: Wang, M., Zhao, J., Avula, B., Wang, Y., Avonto, C., Chittiboyina, A.G., Wylie, P.L., Parcher, J.F., Khan, I.A. 2014. High-resolution gas chromatography/mas spectrometry method for characterization and quantitative analysis of ginkgolic acids in ginkgo biloba plants, extracts, and dietary supplements. Journal of Agricultural and Food Chemistry. 62:12103-12111. https://doi.org/10.1021/jf503980f.
DOI: https://doi.org/10.1021/jf503980f

Interpretive Summary: This manuscript describes a novel analytical method for the analysis of a series of alkyl salicylic (ginkgolic) acids. These compounds are chemically similar to urushiols that are responsible for the deleterious effects of poison ivy and sumac. The concentrations of these acids are strictly regulated to <5 ppm for commercial products containing standardized ginkgo extracts. Thus, the safety of foods and food supplements containing ginkgo materials are directly dependent upon the analytical techniques needed for the analysis of dangerous components such as the ginkgolic acids. The described gas chromatographic technique allows the resolution of the all of the ginkgolic acids including the double bond positional isomers of the C15:1 and C17:1 compounds. The classical method for the analysis of ginkgolic acids is HPLC which cannot resolve such isomers. In most cases, only the total concentration of ginkgolic acids is available. However, any attempt to correlate a given (adverse) pharmacological effect with a specific ginkgolic acid will require an analytical method that allows the quantitation of the individual double bond positional isomers.

Technical Abstract: A high resolution GC/MS with Selected Ion Monitor (SIM) method focusing on the characterization and quantitative analysis of ginkgolic acids (GAs) in Ginkgo biloba L. plant materials, extracts and commercial products was developed and validated. The method involved sample extraction with (1:1) methanol and 10 formic acid, liquid-liquid extraction with n-hexane, and derivatization with trimethylsulfonium hydroxide (TMSH). Separation of 2 saturated (C13:0 and C15:0) and 6 unsaturated ginkgolic acid methyl esters with different positional double bonds (C15:1 Delta 8 and Delta 10, C17:1 Delta 8, Delta 10 and Delta 12, and C17:2) was achieved on a very polar (88% cyanopropyl) aryl-polysiloxane HP-88 capillary GC column. The double bond positions in the GAs were determined by ozonolysis. The developed GC/MS method was validated according to ICH guidelines, and the quantitation results were verified by comparison with a standard HPLC method. Nineteen G. biloba authenticated and commercial plant samples and 21 dietary supplements purported to contain G. biloba leaf extracts were analyzed. Finally, the presence of the marker compounds, terpene trilactones (TTLs) and flavonol glycosides, for Ginkgo biloba in the dietary supplements was determined by UHPLC/MS and used to confirm the presence of G. biloba leaf extracts in all of the botanical dietary supplements.