Hy 100523

PC12 cells are widely used as an in vitro model to simulate neurons [24 ]. PC12 cells were purchased from the Cell Storage Center of Wuhan University, Wuhan, China. PC12 cells were carefully cultured and propagated in a suitable environment at 37°C with 5% CO₂ and 95% air. PC12 cells were cultured in RPMI1640 medium supplemented with 10% fetal bovine serum (FBS, Invitrogen, Carlsbad, CA, USA), 100 U/mL penicillin, and 100 U/mL streptomycin. Control cells were cultured in RPMI1640 complete medium. For the H₂O₂ group, H₂O₂ (the OS inducer, 200 μM) was incubated to simulate OS for 2 h. To assess the impact of maltol and Nrf2 signal, maltol (2 mM) and the Nrf2 inhibitor ML385 (5 μM, HY-100523, MedChemExpress, USA) were applied for 12 h before H₂O₂ treatment.

EEC cells were treated with 0, 12.5 or 25 μM heme (H8130, Solarbio, Beijing, China), and the relevant cells were collected after 48 h. EEC cells were treated with HO-1 inhibitor (Zinc Protoporphyrin, 5 μM, HY-101193, MedChem Express, NJ, USA) or Nrf2 inhibitor (ML385, 5 μM, HY-100523, MedChem Express, NJ, USA), and the relevant cells were collected after 24 h.

Folin–Ciocalteu reagent, Trolox, TPTZ, DPPH, ABTS, and H₂O₂ were acquired from Sigma-Aldrich (Shanghai, China). Authentic standards of compounds for UHPLC-DAD analysis were purchased from Chengdu Purechem-Standard Co., Ltd. (Chengdu, China). GPA used for the cell experiment was acquired from MedChemExpress (≥98%; 27741-01-1; Monmouth Junction, NJ, USA). CCK8 cell viability testing kit was acquired from (GK10001; GlpBio, CA, USA). ROS probes CM-H₂DCFDA were acquired from (C6827; Invitrogen, CA, USA). ESF tea was purchased from Fangjie Agricultural Development Co., LTD (Lingbao, China). ML385 (99.72%; HY-100523), MK2206 (99.92%; HY-108232), and SC66 (99.82%; HY-19832) were purchased from MedChemExpress (Monmouth Junction, NJ, USA).