Elucidating the estrogen-like effects and biocompatibility of the herbal components in the Qing' E formula

The Qing' E Formula (QEF) is a compound preparation that was originally recorded in the 'Prescriptions of the Bureau of Taiping People's Welfare Pharmacy' during the Song Dynasty (10th century CE). It consists of four Chinese medicinal herbs, Eucommiae Cortex (Eucommia ulmoides), Psoraleae Fructus (Psoralea corylifolium), Juglandis Semen (Juglans regia), and Garlic Rhizoma. According to traditional Chinese medicine (TCM), QEF has the ability to tonify the kidney and strengthen muscle and bone. According to the 'kidney governing bone' theory in TCM, QEF is also used to treat the symptoms of climacteric syndrome, especially osteoporosis caused by reduced production of estrogen during the perimenopausal period; however, the therapeutic roles of the individual components of the QEF and their compatibility within the formula has not been investigated.

In this study, the compatibility mechanism and estrogen-like action properties of the four herbal components in the QEF was elucidated according to the organizing principle of Chinese medicine formulas using both in vitro and in vivo models.

The estrogen-like effects of QEF and its herbal components were investigated in MCF7 and HEK293 cells as well as ovariectomized (OVX) rats. The estrogen-like effects of the QEF and its components were analyzed in vitro using Cell Counting Kit-8 and Luciferase reporter gene assays. In the in vivo studies, the blood plasma levels of hormones, lipids, neurotransmitters, aromatase, superoxide dismutase (SOD), and malondialdehyde (MDA) were measured through enzyme-linked immunosorbent assays (ELISAs). The histological morphologies of the target organs after exposure to QEF were investigated by HE staining and immunohistochemical methods. The expression levels of estrogen pathway-related proteins and genes in the OVX rats were measured by Western blotting and real time quantitative PCR (RT-qPCR), respectively.

The in vitro results showed that the QEF, Eucommia (EC) and Psoralea (PF) promoted the proliferation of MCF-7 cells and upregulated the expression of ERα, ERβ and pS2 genes in the MCF-7 cells. Notably, the QEF demonstrated the most active estrogen-like effects compared to the individual ingredients. The in vivo results showed that the QEF, EC, and PF increased the uterine coefficient, upregulated the expression of both ERs (ERα and ERβ) in the uterus, and increased blood serum hormone levels. QEF and its individual components ameliorated menopausal-derived lipid metabolism dysfunction, increased neurotransmitter production by stimulating the adrenal glands, enhanced the antioxidant activity in the serum by increasing the concentration of SOD, reversed ovariectomy-derived atrophy in the uterus, and reduced the weight gain associated with estrogen reduction in the OVX rats. The QEF also antagonize the loss of appetite of OVX animals caused by feeding Psoralea alone, which could explain the compatibility mechanism of Qing' E Formula with reducing toxicity and increasing efficiency.

The estrogen-like effects of Eucommia and Psoralea were mainly mediated through activation of ERα and ERβ. The phytoestrogen components regulated hormone production and the expression of related proteins and genes, which indicated that these components exhibited estrogen-like therapeutic effects. However, the QEF showed the greatest estrogen-like effects compared to the individual components. Overall, this corroborated the therapeutic prowess of the QEF and clarified the pharmacodynamic interactions between the different components extracts in the QEF.