Women present unique morbidities as a distinct subgroup within AS due to physiological differences from men (Nabel, 2000). The onset of atherosclerosis in women occurs 7–10 years later than in men, with premenopausal women experiencing only 1/10∼3/10 of the morbidity observed in men. However, the incidence of atherosclerosis in women significantly escalates during the perimenopausal and postmenopausal phases. Among women aged 60 and above, the prevalence of AS is not significantly different from that in men (Gonzales et al., 2020). Estrogen deficiency during postmenopause (PM) significantly increases atherosclerosis-related morbidity and mortality. The clinical phenomenon of increased cardiovascular risk in PM women is generally attributed to the cardiovascular protective effect of estrogen, although its exact mechanism remains incompletely understood. The ELITE study suggested that estrogen replacement therapy (ERT) can reduce intima-media thickness of the carotid artery in women within 6 years of menopause, and reduce the incidence rate of coronary heart disease of postmenopausal women in the window period (age<60 years) (Hodis et al., 2016; Tuomikoski and Mikkola, 2014). However, ERT is associated with increased risks, including deep vein thrombosis and endometrial cancer (Gartlehner et al., 2017). Hence, there is an urgent need for estrogen substitutes that can confer cardiovascular protective effects while mitigating the mentioned side effects, presenting a crucial area for clinical exploration.

Phytoestrogens (PEs) exhibit estrogenic activity by specifically binding to estrogen receptors. Notably, PEs possess pharmacological properties that mimic estrogen, conferring cardiovascular protection without the associated risks of thrombosis and cancer. Studies indicate that PEs exhibit a positive impact similar to estrogen replacement therapy (ERT) in alleviating menopausal syndrome and postmenopausal osteoporosis (Kargozar et al., 2017). Consequently, PEs represent an ideal approach for preventing and treating postmenopausal atherosclerosis in women, offering promising avenues for research and development. These phytoestrogens are abundant in various traditional Chinese medicines, providing a novel pathway for the exploration of safe and effective pharmaceuticals targeting atherosclerosis in menopausal individuals. Mechanistically, AS is a chronic inflammatory disease. GPER is a receptor situated on the cell membrane that is coupled with G proteins. Estrogen exerts its anti-AS effect by inhibiting endothelial cell inflammation through GPER-mediated mechanisms (Huang et al., 2021), and has been shown to inhibit the progression of ferroptosis in hepatotoxicity (He et al., 2023). Ferroptosis, identified as a critical player in AS lesions, is characterized by lipid peroxidation, contributing to oxidative stress within endothelial cells. This process leads to vascular endothelial dysfunction, promoting the onset and progression of AS (Stockwell et al., 2017). Recent studies have unveiled ferroptosis as a lysosome-associated form of cell death (Gao et al., 2018). TRPML1 emerges as a potential target for treating lysosomal storage disorders (Dong et al., 2008).TRPML1 impedes the degradation of GPX4, thereby suppressing ferroptosis and mitigating the adverse consequences on renal function (Liu et al., 2024). However, whether GPER ameliorates postmenopausal atherosclerosis by modulating TRPML1-mediated ferroptosis is unknown. Further exploration of this pathway promises valuable insights into potential therapeutic interventions for postmenopausal atherosclerosis.

Professor Dong Qimei, a distinguished Chinese medicine expert from Jiangsu Provincial Institute of Traditional Chinese Medicine, developed QiXian granule (QXG) based on extensive clinical experience for treating atherosclerosis induced by estrogen deficiency. It consists of Astragalus membranaceus (Fisch.) Bunge, Salvia miltiorrhiza Bunge, Epimedium brevicornu Maxim and Cajanus cajan (L.) Druce, which play the role of replenishing qi, activating blood and tonifying the kidneys (Table 1). Names have been checked with http://www.theplantlist.org mentioning the data of accessing that website. QXG incorporates various flavonoids, recognized for their estrogen-like effects (Bae et al., 2018; Matsumoto et al., 2018). With over 30 years of clinical application, QXG has demonstrated significant efficacy in improving postmenopausal atherosclerosis. Our previous studies have found that QXG inhibited ISO-induced myocardial remodeling by the mechanism related to the negative regulation of the stimulatory G-protein alpha subunit (Gsα)/inhibitory G protein alpha subunit (Giα), thereby inhibiting the activation of the phosphatidylinositol-4, 5-bisphosphate (PIP2)-inositol 1, 4, 5-triphosphate (IP3)–Ca2+-calcineurin (CaN) signaling pathway (Wang and Qi, 2018). Our further study revealed that the effective key ingredient in this classic formula, Icraiin, inhibits ferroptosis by promoting xo-LDL-induced vascular endothelial cell injury and autophagy in atherosclerotic mice, thus contributing to the treatment of atherosclerosis (Wang et al., 2023). Another active ingredient, Salvianolic Acid B, suppress ferroptosis and apoptosis during myocardial ischemia/reperfusion injury by reducing ubiquitin-proteasome degradation of GPX4 and down-regulating the ROS-JNK/MAPK pathway (Xu et al., 2023). Therefore, in this study, we established the Ovx/ApoE−/− mice model to investigate the protective effect of QXG against postmenopausal AS and to investigate whether it regulates TRPML1-mediated ferroptosis through GPER to improve postmenopausal atherosclerosis.