Flavonoid-rich fraction of <i>Cyclocarya paliurus</i> enhances osteogenic differentiation through the PI3K-AKT signaling pathway in MC3T3-E1 cells

Four types of macroporous resins (HPD-600, AB-8, D-101, and DM130) and a polyamide resin were compared for efficiency to extract total flavonoids from <i>Cyclocarya paliurus</i> (Batal.) Iljinskaja (CPF). Among them, HPD-600 was identified as the most effective. The ideal adsorption conditions were determined to be as follows: 70% ethanol was used as the eluent, with a flow rate of 2 BV/h and a CPF concentration of 1.0 mg/mL. Purification using HPD-600 resin resulted in a CPF yield of 69.76% ± 2.3%. Furthermore, in CPF-treated MC3T3-E1 cells, the osteogenic proliferation and differentiation activity were evaluated. At a concentration of 200 μg/mL, CPF enhanced cell viability, without significantly affecting cell proliferation as assessed by Ki67 staining. CPF promoted osteogenic differentiation by ALP staining. Our study is the first to demonstrate that CPF enhances osteogenic differentiation <i>via</i> activation of the PI3K-AKT-FOXO1 signalling pathway in MC3T3-E1 cells, highlighting its potential as a novel anti-osteoporotic agent.