β-sitosterol improves the pathological progression of PCOS by targeting ESRα to inhibit autophagy activity

Background Polycystic ovary syndrome (PCOS) is a prevalent hormonal disorder among women, mainly marked by elevated levels of androgens, irregular ovulation, and the presence of multiple cysts in the ovaries. Eucommia, as a common traditional Chinese medicine for treating PCOS in clinical practice, has β-sitosterol as its main active ingredient. Currently, the mechanism by which Eucommia ulmoides alleviates the pathological progression of PCOS has not been fully explored. Purpose This study aims to explore the mechanism of β-sitosterol in treating the pathological changes of PCOS. Methods Employ ultra-high performance liquid chromatography-mass spectrometry to identify the primary active compounds of Eucommia ulmoides, and investigate its possible targets and mechanisms for addressing PCOS using network pharmacology. Molecular docking and molecular dynamics simulations are used to verify the potential interaction and binding of compounds with target proteins. The molecular biology experiments exploring the therapeutic mechanisms were conducted using a PCOS model constructed with rats and KGN cells. Results Both network pharmacology and ultra-high performance liquid chromatography-mass spectrometry results indicate that β-sitosterol is the main active component of Eucommia ulmoides. Furthermore, network pharmacology findings suggest that the potential targets of β-sitosterol for treating PCOS are primarily located within the steroid metabolism pathway. Notably, molecular docking and molecular dynamics simulations reveal that β-sitosterol interacts closely with ESRα and AKT. Both in vivo and in vitro studies have shown that β-sitosterol can prevent the apoptosis of granulosa cells and excessive autophagy activation in PCOS. Furthermore, β-sitosterol exerts an ovarian protective effect by inhibiting autophagy and the apoptosis of granulosa cells through its targeted action on ESRα and AKT. Conclusions Our research found that β-sitosterol downregulates autophagy activity through the ESR1/AKT/mTOR signaling pathway, thereby inhibiting the apoptosis of granulosa cells and alleviating the pathological progression of PCOS.