Quality structural annotation for the metabolites of chlorogenic acid in rat

Chlorogenic acid (CA) serves as a principal contributor for the health benefit spectrum of tea; however, its metabolism pattern hasn't been completely clarified. We attempted here to profile CA metabolism through fortifying isomer identification ability onto LC-MS/MS. Online energy-resolved MS was applied to configure full collision energy ramp-MS2 spectrum. Quantum structural calculation was undetaken to pursue the relationships between chemical structures and optimal collision energy/the maximum relative ion intensity. Thirty-seven metabolites were captured in biological matrices. Plausible structures were configured by applying the empirical mass fragmentation rules to m/z values and the summarized relationships were utilized to drive the plausible structures to confidence-enhanced identities. Hydrolysis, glucuronidation, sulfation, acyl migration, oxidation, and hydrogenation occupied primary metabolism channels. Together, the current study disclosed in depth the metabolism profile of CA and moreover, suggested a versatile analytical route for quality metabolite identification.