Norartocarpetin, quercetin and naringenin were found to effectively inhibit 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) formation through trapping its phenylacetaldehyde and form their adducts in roast beef patties. Six adducts [8-C- or 6-C-(E-phenylethenyl) flavonoids] formed between phenylacetaldehyde and three flavonoids were detected in roast beef patties by UPLC-MS analyses and compared with their synthetic references. These flavonoid-phenylacetaldehyde adducts were synthesised and further subjected to cytotoxicity tests on three liver cancer cell lines HepG2, SMMC-7721 and QGY-7703. The adduct 8-C-(E-phenylethenyl)norartocarpetin (NARA1) was found to significantly induce cancer cell death with IC50 values about 7 μM. After pre-treating with MAPK and caspase inhibitors, alteration of the cell morphology and cleaved-PARP were detected in liver cancer cell lines administered with NARA1. These data indicated that norartocarpetin could inhibit PhIP formation in roast beef patties and form norartocarpetin-phenylacetaldehyde adducts. The adduct NARA1 has anticancer potential via intrinsic caspase-dependent and cell context-dependent MAPKs pathways.
Keywords: 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP); Cytotoxicity effects; Flavonoids; Flavonoid–phenylacetaldehyde adducts; Phenylacetaldehyde.
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