Optimization of Extraction Process of Total Flavonoids from Loquat Leaves and Its Protective Effect on H9C2 Cells in Hypoxia Injury

To study the reflux extraction process of total flavonoids from loquat leaves and to investigate its protective effect on H9C2 cells in hypoxia injury. An orthogonal test was utilized to optimize the reflux extraction process parameters, Na₂S₂O₄ was used to induce myocardial cell hypoxia injury, MTT assay was used to evaluate cell survival rate, CK, LDH, SOD, MDA were used to evaluate the hypoxia injury of H9C2 cells. The optimized process condition for reflux extraction was 10 times the amount of 70% ethanol for 3 times, each time for 2 h. The extracted content of TFL was 37.12 mg/g under this condition, and the TFL was found to increase cell survival rate, decrease the levels of CK, LDH, MDA, and improve SOD levels. The favored reflux extraction process of loquat leaves is stable and feasible, and the TFL have a good protective effect on H9C2 cells in hypoxia injury.