ANALYSIS AND STRUCTURE IDENTIFICATION OF TRACE CONSTITUENT IN THE TOTAL GINKGOLIDE BY USING LC/DAD/ESI/MS

AIM To identify the trace constituents in the total ginkgolide from leaves of Ginkgo biloba. METHODS The extract was analyzed by using LC/DAD/ESI/MS combination technology, both UV and mass spectrums of each compound were recorded simultaneously. UV, IR, MS and NMR spectra were employed for structural identification. RESULTS With higher sensitivity of the MS detector, three trace constituents were found as well as the known compounds ginkgolide A (GA), ginkgolide B (GB), ginkgolide C (GC) and bilobalide (BD). CONCLUSION Two compounds (t_R 57.8 and 56.7 min) were identified as 1,10 dihydroxy-3,14-didehydroginkgolide and 10-hydroxy-3,14-didehydroginkgolide, named as ginkgolide K and ginkgolide L, respectively, according to the characteristics of their UV, MS, IR and NMR spectra. It is the first time of finding the ginkgolide compounds containing double bond.