Polycystic ovary syndrome is an endocrine syndrome associated with ovulatory disorders and metabolic abnormalities. Since the main external characteristics of the disease are infrequent menstruation and prolonged infertility, in TCM, PCOS is mostly classified as "late menstruation", "less menstruation", "amenorrhea", "collapse", and "infertility". The etiology and pathogenesis of the disease (in TCM) involve kidney-Tiangui-Chongren-cycle axis dysfunction, phlegm dampness, and obstruction in the middle focus, with heat over time, resulting in kidney, liver, and spleen dysfunction. Coptis chinensis is a representative medicine for clearing away heat and dampness in TCM. At present, most clinical studies focus on the effect of the berberine extract component ("berberine"), but pharmacological studies have found that a Huang Lian (Chinese Herb) decoction is better than berberine monomers in improving insulin resistance, lowering blood sugar, and improving glucose and lipid metabolism disorders [12, 13]. Due to the complex composition of TCM CC, many ingredients often participate in the process of exerting its effects, and the mechanisms of action are intertwined with each other. Therefore, it is necessary to conduct a comprehensive analysis on the relevant network pharmacology software platforms to interpret the mechanisms of action.
In this study, the main active ingredients of CC were found to include various organic components such as berberone, berberine, quercetin, canadine, and berberrubine. The core nodes in the "target" network suggest that these several active ingredients play a very important role in the treatment of PCOS. Other related studies have also verified that several components in CC improve follicular developmental disorders, ovulatory disorders, and lower fasting blood glucose and fasting insulin levels to reduce insulin resistance in women with PCOS [14, 15], concurring with the current study. A large, multicenter, randomized, double-blind, placebo-controlled trial of berberine in PCOS showed that berberine combined with the first-line, ovulation-promoting agent, letrozole, can improve ovulation rate and pregnancy [16]. In addition, berberine has the advantage of lowering the incidence of adverse gastrointestinal reactions and severe ovarian hyperstimulation syndrome, compared with letrozole.
Through analysis of drug and disease targets, it was found that quercetin has 139 targets, which are active ingredients with many targets. Quercetin is a natural flavonoid, which can inhibit the activity of aldose reductase, and has the effect of reducing the advanced glycation end products (AGEs) and insulin resistance. It has attracted the attention of researchers and clinicians [17]. The use of quercetin in the treatment of type 2 diabetes is becoming increasingly common. Treatment of diabetic rats with quercetin and metformin improved insulin sensitivity and increased liver glycogen levels, suggesting that the two substances act in a similar way [14]. In addition, quercetin can change the body composition of patients with obesity and dyslipidemia, thereby improving body metabolism and hormone levels [7]. Therefore, quercetin is also gradually applied to improve the treatment of patients with PCOS.
Analysis of the PPI network indicated that MAPK, JUN, IL-6, CXCL8, and FOS are at the core of the network and can be regarded as potential key targets for CC in treating PCOS. MAPK (a mitogen-activated protein kinase pathway) is involved in the regulation of oocyte maturation, and this effect is essential for normal follicular development and proper ovulation [18]. Once the MAPK pathway is blocked, mitotic cyclin D2 expression and the role of granulocyte proliferation will be impeded, resulting in a decrease in the number of granulocytes, which indirectly interferes with the development and maturation of follicles [19, 20]. Experiments have confirmed that the high expression of IL-6 in PCOS may play a role in the pathogenesis of PCOS through the synergistic effect of insulin resistance and chronic inflammation [21]. The abnormally low expression of the FOS gene in granular cells may increase the androgen secretion of ovarian granular cells by reducing the inhibitory effect on the CYP17 gene [22]. The results of molecular docking showed that the active ingredient, quercetin, with the most targets, had a higher degree of binding to MAPK, IL-6, CXCL8, and IL-1β, suggesting that the compound may play a therapeutic role by combining with these proteins.
ClueGO biological process enrichment analysis was performed on the key targets of the active components of CC, which confirmed that CC has certain effects on biological processes such as apoptosis, cytokine activation, oxidant antioxidant, and nitric oxide metabolism. The process is reflected in the targets and related pathways involved in the treatment of PCOS by CC. In the KEGG enrichment analysis, CC was shown to regulate various PCOS pathogenesis-related signaling pathways including AGEs/RAGE, MAPK, PI3k/Akt, and TNF. Studies have shown that the high expression of AGEs plays a key role in the formation of PCOS. AGEs mainly bind to specific receptors (RAGE), and mediate a series of pathological responses through cellular signal transduction mechanisms [23].
Studies have found that after binding to AGEs, RAGE can inhibit the activation of phosphatidylinositol 3-kinase (PI3K / Akt) and the expression of related genes in the course granule cells, so that the glucose transporter (GLUT4) can be transferred to the plasma membrane. Obstacles, inhibition of glycogen synthesis, inhibition of glycolysis, promotion of gluconeogenesis, inhibition of protein synthesis, and changes in gene expression promote elevated blood glucose, severe hyperinsulinemia, and IR. In the process of follicular development, oocytes find it difficult to synthesize glucose, and most of their energy comes from granulocyte glycolysis [24]. Therefore, AGEs/RAGE may reduce glucose intake by reducing the number of granulocyte membrane GLUT⁃4 receptors and thereby reduce glucose intake, affecting oocyte growth [20]. In addition, up-regulated RAGE may reduce the sensitivity of granulocytes to follicle stimulating hormone (FSH) by inhibiting the MAPK/ERK 1/2 pathway and promoting increased apoptosis of granulosa cells [18, 19]. Therefore, for the treatment of PCOS, the active ingredients of CC can be selected to explore whether they plays a role through certain key targets and pathways. The research results reflect the characteristics of TCM with multiple components, multiple targets, and multiple approaches to treat the disease, and provide a reference for the treatment of PCOS. However, based on some limitations of network pharmacology and mechanical algorithms, it is necessary to further verify the mechanisms of action of CC on PCOS through clinical experiments.