Structure identification of myricetin-phenylacetaldehyde adducts and their potential biological activities

Our previous research discovered that myricetin could effectively inhibit the formation of heterocyclic aromatic amines (HAAs) in cantonese baked foods by trapping phenylacetaldehyde to form adducts. However, the structure and biological activity of these adducts were still unknown. In this study, we identified two myricetin-phenylacetaldehyde adducts from cantonese mooncakes, BYQ-2 and BYQ-3, using pre-HPLC. These adducts were found to be the products of phenylacetaldehyde addition at the C-8 and C-6 positions of myricetin, followed by cyclization with hydroxyl groups at the C-7 and C-5 positions. Antioxidant assays revealed that BYQ-2 and BYQ-3 have stronger radical scavenging abilities than myricetin in the concentration range of 12.5 ∼ 800 μg/mL in the three samples. Additionally, both adducts showed potential health benefits by inhibiting α-glucosidase and CYP450 1A2, enzymes involved in blood sugar regulation and HAAs metabolism. BYQ-2 exhibited the highest inhibitory potency against α-glucosidase and CYP450 1A2 with IC₅₀ values of 10.32 μg/mL and 5.44 μg/mL, respectively. Theoretical calculations suggested that hydrogen bonding and hydrophobic interactions are the primary forces driving enzyme binding, with BYQ-2 showing the highest binding energies (-7.75 kcal/mol for α-glucosidase and -9.31 kcal/mol for CYP450 1A2). Our findings suggested that myricetin inhibited HAAs in baked foods while also enhancing food safety and providing health benefits through its adduction with small molecule aldehydes. In future research, it is necessary to further evaluate the absorption and metabolic behavior as well as safety of myricetin-HAAs active intermediate adducts at the cellular and animal experimental level.