Electrophilic components from Xiaoheiyao (rhizomes of Inula nervosa Wall.) alleviate the production of heterocyclic aromatic amines via creatinine inhibition

Xiaoheiyao is the rhizome of Inula nervosa Wall., a traditional spice and medicinal herb in China. In this study, the creatinine inhibitor from Xiaoheiyao extract and also the effects and mechanism on the production of heterocyclic aromatic amines (HAAs) were investigated. Xiaoheiyao extract inhibited the total contents of seven detected HAAs in grilled beef patties, particularly aminoimidazole-azaarenes (AIAs) in a dose-dependent manner, reaching a maximum inhibition rate of 62% for total HAAs and 73% for AIAs. The most effective subfraction of Xiaoheiyao extract (IER80) contained abundant potential creatinine inhibitors, as revealed by immobilized creatinine probe, HPLC and UPLC-MS/MS analyses. Moreover, electrophilic p-coumaric acid derivatives were discovered from IER80 by feature based molecular networking. p-Coumaric acid was demonstrated to inhibit the contents of total HAAs and AIAs in grilled beef patties and model system. Quantitative analyses of the precursor and intermediates of AIAs in model system revealed that p-coumaric acid mainly affected the generation of AIAs by inhibiting creatinine.