The clinical efficacy of the Sishen Pill in treating UC has been confirmed by multiple clinical studies. Long et al. conducted a meta-analysis of nine randomized controlled trials (RCTs) including 680 patients and found that, compared to sulfasalazine and mesalazine, the combined use of Sishen Pill could effectively improve the effectiveness of treatment, reduce C-reactive protein levels, and have a lower incidence of adverse reactions (Long and Cao, 2021b), however, among the original studies included in this meta-analysis, different studies adopted different forms of administration of Sishen Pills (oral or enema), and it remains to be further explored which administration route can achieve better therapeutic effects. Zhang et al. used network pharmacology and bioinformatics methods to screen 22 key targets of the Sishen Pill in treating UC (Zhang et al., 2019) and suggested that it could improve intestinal inflammatory state, repair intestinal mucosal injury, and inhibit disease progression by regulating multiple targets, however, further experimental research is needed to confirm the relevant conclusions based on bioinformatics analysis. Table 1 lists the relevant basic research progress on the Sishen Pill for the treatment of IBD. Briefly, several studies focused on the inhibitory effects of Sishen Pill on the toll-like receptor (TLR): Huang (Huang et al., 2021) and Zhao (Zhaohua et al., 2022) found that the formula could inhibit expression levels of myeloid differentiation factor 88 (MyD88), interleukin-1 receptor associated kinase 4 (Irak4), and nuclear factor-kappa B(NF-κB) by down-regulating the activation of TLR2. Wang (Wang et al., 2019a) and Ge (Ge et al., 2022) confirmed that TLR4 was the key target, and downregulating TLR4 could inhibit the occurrence of subsequent inflammatory responses through MyD88-dependent and MyD88-independent pathways. In addition, Zhang (Zhang et al., 2021c), Wang (Wang et al., 2022a) and Zhao (Zhao et al., 2013) explored the molecular mechanism of the Sishen Pill in inhibiting the inflammatory response and promoting intestinal mucosal repair via phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/Akt), Janus kinase (JAK)/signal transducer and activator of transcription 5 (STAT5), and mitogen activated protein kinase (MAPK) signal pathways. Moreover, the regulation of intestinal immune cells by Sishen Pill mainly manifests in different subsets of T lymphocytes and regulatory T cells (Treg) (Liu et al., 2016), helper T cells (Th) (Liu et al., 2016), follicular helper T cells (Tfh) (Liu et al., 2020), follicular regulatory T cells (Tfr) (Huang et al., 2022; Kang et al., 2022), memory T cells (TM) (Ge et al., 2020), and dendritic cells (Liu et al., 2022). For regulating the gut microbiota, Sishen Pill has been shown to increase the relative abundance of beneficial bacteria, such as Lactobacillus and Akkermansia, and to promote an increase in intestinal butyrate content (Chen et al., 2020b; Wang et al., 2022b; Ge et al., 2022). In summary, the above studies have elucidated the mechanism of action of Sishen Pill in treating IBD from different perspectives, but there is still a lack of deeper exploration on the key targets of action, and the application of molecular inhibitors/activators or gene knockout animal model and other experimental methods is necessary and anticipated in future research.

The RCT carried out by Sun et al. confirmed that the additional application of Sishen Pill in chemotherapy could significantly improve the patient’s discomfort symptoms, enhance the treatment effectiveness, reduce the probability of chemotherapy side effects (e.g., leukopenia, thrombocytopenia, liver and kidney function injury), and regulate immune cell levels (CD8⁺ cells↓, CD3⁺ and CD4⁺ cells↑) (Sun et al., 2021). Another clinical study revealed the therapeutic mechanism of the Sishen Pill in treating colon cancer from the perspective of gut microbiota. Researchers found that the richness and diversity of fecal microbiota in postoperative colon cancer patients were lower compared to healthy individuals; the Sishen Pill could improve this trend (Tan et al., 2023). For patients undergoing radical resection of colorectal cancer, Sishen Pill could not only alleviate clinical symptoms such as abdominal distension, tiredness, knee pain, waist acid, and cold but also reduce the tumor marker CEA and immune function indexes CD8⁺ and CD8⁺/CD4⁺ and increase the level of CD4⁺ (Zhang Y. et al., 2021). It should be pointed out that all three clinical studies mentioned above exist some methodological flaws, for example, not using a double-blind study design, and lacking relevant descriptions about allocation concealment, which to some extent reduces the reliability of clinical trial results; besides, these studies have not adopted the core indicators of clinical research on colon cancer, such as whether it can improve the survival rate of patients? Longer follow-up periods are necessary in the further research. The cell experiment on the molecular mechanism of Sishen Pill treating colon cancer showed that serum medicated with 10% Sishen Pill could downregulate the viability of HCT116 cells and the expression level of glucose transporter 1 (GLUT-1) and promote the activation of enzymes related to aerobic glycolysis, such as hexokinase and fructose-6-phosphate kinase. It could also decrease the overexpression of methyltransferase-like 3 protein and inhibit m⁶A RNA methylation, suggesting that Sishen Pill could regulate the glycolysis process by intervening in epigenetic modification, thereby inhibiting the proliferation of colon cancer cells (Jiang et al., 2023). In addition to the direct anticancer effect, Cao et al. also carried out research on the molecular mechanism of the Sishen Pill in inhibiting the transformation of colonic inflammatory lesions to colon cancer and found that the formula could downregulate the expression levels of nuclear factor e2-related factor 2 (Nrf2) and cyclooxygenase-2 (COX-2) in colon tissue, reducing the cancer formation rate of dextran sodium sulfate (DSS)-induced colitis mice; both oral and enema administrations had significant curative effects (Cao et al., 2012; Cao, 2013). In short, some studies also indicated the clinical effectiveness and molecular mechanism of Sishen Pill in the treatment of colon cancer; however, higher-quality clinical research and deeper mechanistic explorations are needed.

Zhou et al. studied the pharmacological effects and molecular mechanisms of psoralen, isopsoralen, and bakuchiol in treating IBD and confirmed that psoralen is the core pharmacodynamic substance and that the mechanism might be associated with the homeostasis of bile acids regulated by farnesoid X receptor (FXR)-fibroblast growth factor 15 (FGF15) pathways (Zhou, 2020). Ami et al. applied network pharmacology to identify 13 metabolites with good bioavailability after the oral administration of Psoraleae Fructus; and 11 metabolites could significantly reduce the overproduction of nitric oxide (NO), tumor necrosis factor- α (TNF-α) and interleukin-6 (IL-6) in macrophages induced by lipopolysaccharide (LPS) (Lee et al., 2023). Besides, network pharmacology analysis has also been used to explore molecular mechanism of isobavachalcone, an active metabolite of Psoralea Fructus, in the treatment of IBD, and Yang et al. confirmed AKT1, matrix metalloprotein 9 (MMP9), epidermal growth factor receptor (EGFR), insulin-like growth factor 1(IGF1), and steroid receptor coactivator (SRC) were its core targets (Yang et al., 2023a). The identification of effective metabolites is a key focus of botanical drug research, and the above studies is mainly based on the drug concentration in the blood, or bioavailability as the main screening criterion, which may inevitably overlook the indispensable effects of some metabolites with poor bioavailability, and they may exer intestinal protective effect by regulating the gut microbiota or microbial metabolites, rather than entering the peripheral loop. In addition, bakuchiol (Lim et al., 2019) and bavachin (Hung et al., 2019) have been shown to have ideal anti-inflammatory activities, and can they effectively treat IBD? Further research is needed for confirmation.

In recent years, the anticancer activity of various metabolites contained in Psoraleae Fructus has received widespread attention. For example, psoralen can inhibit the invasion and metastasis of human colon cancer HCT-116 cells, and its mechanism may be related to the downregulation of β-catenin, TCF4 proteins, their downstream target genes, vascular endothelial growth factor (VEGF), and MMP-9. Similarly, psoralidin was confirmed to reduce cell viability and enhance cell apoptosis by inhibiting the NF-κB and Bcl-2/BCL-2 associated X (Bax) signaling pathways (Jin et al., 2016); concurrently, it could also trigger oxidative damage-mediated apoptosis via rapidly boosting reactive oxygen species (ROS) generation (Sun et al., 2022). Bakuchiol can activate c-Jun N-terminal kinase (JNK) phosphorylation, induce ROS generation, and regulate the expression of death receptors and various anti-apoptotic proteins (Park et al., 2016). In addition, bavacin and 8-methoxypsoralen activate caspases by suppressing the MAPK and PI3K/AKT pathways, thereby promoting cancer cell apoptosis (Bartnik et al., 2017; Wang et al., 2023a) (see Table 2 for further details).

Studies found that myristicin and linalool, two main metabolites in Myristica Semen, could exert anti-inflammatory and antioxidant effects by regulating the expression levels of NF-κ B and Nrf-2 (Tekeli et al., 2018; Ismail Abo El-Fadl and Mohamed, 2022). Compared to using diclofenac alone, the composite formulation of diclofenac and eugenol could better inhibit the nuclear translocation of NF-κB by activating the Nrf2/heme oxygenase-1 (HO-1) signaling pathway, thereby demonstrating better therapeutic effects against UC (Wang et al., 2023c). Zhang et al. developed a new phospholipid nanovesicle containing the volatile oil medicine eugenol to treat UC and confirmed that it was more conducive to percutaneous absorption and had better clinical efficacy (Zhang et al., 2020c).

In investigating Myristica Semen in treating colon cancer, Chen et al. used a network pharmacology method to screen nine active metabolites including galbacin and 24 core targets (Chen et al., 2023). Piras et al. (2012) identified the anticancer activity of essential oils and myristicin extracted from Myristicae Semen, confirming that they had a significant inhibitory effect on the growth of a colon cancer cell line (undifferentiated Caco-2 cells). In addition, Duan et al. (2020) showed that myristicin could inhibit the proliferation, migration, and invasion of colon cancer cells and induce cellular apoptosis by regulating the mitogen-activated protein kinase (MAPKK/MEK)/extracellular regulated protein kinase (ERK) signaling pathway. In addition, the regulatory effect of linalool on the oxidative response was beneficial for the treatment of colon cancer; it was confirmed that cellular apoptosis was induced by promoting the production of hydroxyl radicals and 4-HNE (a marker of oxidative stress due to increased lipid peroxidation) (Iwasaki et al., 2016). Moreover, some studies focused on the inhibitory effects of eugenol, isoeugenol, and dihydrodiiisoeugenol on colon cancer cells, showing that their anti-cancer mechanisms involve the regulation of metabolic pathways, apoptosis/metastasis-related gene expression, and the activation of endoplasmic reticulum stress-induced inhibition of autophagy (Li et al., 2021a; Ghodousi-Dehnavi et al., 2021; Bilgin et al., 2023). In above studies, Iwasaki et al. (Iwasaki et al., 2016) and Li et al. (Li et al., 2021b) used the tumor xenograft model in their experiments, while evidence from other studies mainly came from cell experiments. Generally speaking, the anti-tumor effects of botanical drugs are not single target or single pathway, and there exist complex interactions between different molecular pathways. It is crucial to explore the overall effects in tumor xenograft animal models, which greatly increases the credibility of research results. Further details are presented in Table 3.

Studies suggested that NF-κB was the key target of evodiamine in the treatment of IBD, and downregulating NF-κB pathway proteins and inhibiting NOD like receptor heat protein domain related protein 3 (NLRP3) expression could alleviate inflammation-induced cell damage and repair the intestinal mucosal barrier (Shen et al., 2019; Ding et al., 2020). Simultaneously, evodiamine could also promote the regulation of the gut microbiota, especially by increasing the relative abundance of the beneficial bacterium Lactobacillus and intestinal acetate content, inhibiting the proliferation of the pathogenic Escherichia coli, and reducing plasma LPS and various inflammatory factor levels (Shen et al., 2019; Wang et al., 2020c; Ding et al., 2020). Another study suggested that kelch-like ECH-associated protein 1 (KEAP1) is a key target of rutecarpine, inhibiting the interactions between KEAP1 and Nrf2 by binding to the KEAP1 kelch domain, thereby activating Nrf2, promoting its nuclear translocation, upregulating the Nrf2-mediated antioxidant response, and achieving the pharmacological effect of improving intestinal mucosal injury (Zhang et al., 2020b).

In parallel, Chien et al. found that evodiamine could activate the MAPK signaling pathway and induce cell apoptosis and G2/M arrest by upregulating the phosphorylation levels of ERK and JNK proteins (Chien et al., 2014). Other researchers (Huang et al., 2015), Zhu (Zhu et al., 2021), and Zhang (Zhang et al., 2022) suggested that the anti-inflammatory effects of evodiamine also involved PI3K, STAT3, and NF-κB signaling pathways. In addition, evodiamine can reverse the epithelial-mesenchymal transition of tumor-associated fibroblasts induced by promoting the phosphorylation of Smad2 and Smad3, thereby reducing the migration and invasion abilities of tumor cells (Yang et al., 2019). In addition, Woong et al.’s research confirmed that rutecarpine could also inhibit wingless-type MMTV integration site family (Wnt)/β-catenin-mediated signaling pathway, thereby downregulating the expression levels of epithelial mesenchymal transition biomarkers such as MMP-7, Snail, and N-cadherin (Byun et al., 2022). Li et al. developed an EGFR targeting evodiamine-encapsulated polyamino acid nanoparticles to resolve the issue of low solubility and bioavailability and compared it with the traditional evodiamine formulation. The new preparation significantly increased the cytotoxicity of colon cancer cells and inhibited cell adhesion, invasion, and migration (Li et al., 2019a). Others have designed new metabolites based on evodiamine that have shown promising antitumor activity (Wang et al., 2020a; Li et al., 2020b). It should be pointed out that the dosage of evodiamine is still controversial in different studies. The minimum dose is 1 mg/kg, while the maximum dose is 40 mg/kg. It can be seen that a more detailed dose-response and dose-toxicity relationships of evodiamine needs to be further determined, which is crucial for guiding the clinical application. Further details are presented in Table 4.

Multiple schisandrins have definite therapeutic effects in IBD. For example, schisandrin A (Wang et al., 2023b), schisandrin B (Liu et al., 2015), schisandrin C (Kim et al., 2022) and deoxyschizandrin (Yu and Qian, 2021) inhibited the NF-κB nuclear translocation and downstream pro-inflammatory signaling pathway activation; schisandrin B could also regulate AMPK/Nrf2, affect NLRP3 inflammasome, and then alleviate cell pyroptosis and intestinal epithelial damage caused by immune inflammation. In addition, Wang et al. conducted a pharmacokinetic analysis of seven different types of lignin in Schisandrae Chinensis and found that C_max and AUC_0-∞ of schisandrin were significantly higher than those of other lignans; they also confirmed that it could treat UC by inhibiting the serum/glucocorticoid regulated kinase 1 (SGK1)/NLRP3 pathway and regulating the gut microbiota (Wang et al., 2023d).

Some studies focused on the therapeutic effects of metabolites in Schisandra Chinensis on colon cancer. Casarin et al. found that two types of lignins in Schisandrae Chinensis, (+)-deoxyschisandrin (1) and (−)-gomisin N, could induce the apoptosis of colon adenocarcinoma cells (LoVo); the mechanism was related to the downregulation of cyclin B protein expression, mediating G2/M phase arrest (Casarin et al., 2014). Schisandrin A has also been proven to have a regulatory effect on the cell cycle; it could downregulate the expression of HO-1 protein through the Nrf-2 signaling pathway, thereby reducing the production of reactive oxygen species and nitrogen oxides. However, it could also block NF-κB nuclear translocation and the activation of MAPKs to inhibit inflammatory response (Wan et al., 2019). Some studies focused on the therapeutic potential of Schisandrae Chinensis in inhibiting the “inflammation-cancer transformation.” Li et al.’s experiment confirmed that schisandrin B could inhibit the occurrence of colitis-associated cancer by regulating the gut microbiota and activating the phosphorylation of focal adhesion kinase and its downstream kinase (Li et al., 2019b). Pu et al. (2021) found that the pharmacological effect of schisandrin B in inhibiting the proliferation and metastasis of colitis-related tumors was related to the downregulation of silencing regulatory protein 1(SIRT1) and inducing the expression of smad ubiquitination regulatory factor 2 (SMURF2) (Pu et al., 2021). The anti-tumor activity of some non-specific active substances of Schisandrae Chinensis, such as citral, cannot be ignored either; the experiment by Sheikh et al. confirmed that citral could inhibit the proliferation of HCT116 and HT29 cells in a dose-dependent and time-dependent manner; its mechanism was related to mediating the phosphorylation of p53 protein and promoting the mitochondrial release of apoptogenic factors (Sheikh et al., 2017). See Table 5 for more details.

Chronic inflammation is not only an important feature of IBD but also a driver of the onset and development of colon cancer. Studies have found that chronic intestinal inflammation can cause DNA double chain breaks, oxidative stress damage, and epigenetic changes in intestinal epithelial cells, upregulate oncogenes, downregulate cancer suppressor genes, and promote the occurrence of dysplasia and cancer (Shah and Itzkowitz, 2022). Regulation of the inflammatory response is the core mechanism of Sishen Pill in treating IBD and inhibiting inflammation-cancer transformation, which involves multiple inflammation-related signaling pathways (Figure 2).

Many mechanistic studies on Sishen Pills focus on the regulatory effects of the NF-κB pathway (Wang et al., 2019d; Ge et al., 2022; Zhaohua et al., 2022). NF-κB is a classical key inflammatory modulator. LPS and other pro-inflammatory factors activate TLRs, induce NF-κB nuclear translocation, and regulate the gene expression of a variety of inflammatory mediators. In particular, LPS can promote the increase of TNF-α and multiple interleukins that act on macrophages to produce many inflammatory mediators and continuously induce NF-κB nuclear translocation to form a positive feedback cascade amplification effect. The basic activity of NF-κB is necessary for the normal proliferation and differentiation of cells to maintain the immune balance of epithelial tissue and inhibit the interference of inflammation on pithelial tissue homeostasis (Iacobazzi et al., 2023). Recently, a number of studies have focused on the role of NF-κB in promoting tumor cell apoptosis. As a landmark cell cycle protein, cyclinD1 is also the target gene of NF-κB. The continuous activation of NF-κB can initiate cyclinD1 transcription, promote the G1/G0 phase-to-S phase transition, and lead to abnormal cell proliferation and cancer. Thus, inhibiting NF-κB activation or blocking its downstream key proteins is considered an important target for developing new antitumor drugs (Taniguchi and Karin, 2018; Deka and Li, 2023).

The pharmacological effects of the Sishen Pill in the treatment of IBD and colon cancer are also related to the regulation of the MAPK and PI3K/Akt signaling pathways. Extracellular regulated protein kinases (ERK)1/2, c-JNK, p38, and ERK5 are the main members of the MAPK family, and there is also extensive cross talk between different pathways: ERK mainly regulates cell growth and differentiation; JNK and p38 play more important roles in stress responses such as inflammation and cell apoptosis; and ERK5 can regulate pathological processes such as cell cycle acceleration and endothelial cell proliferation caused by growth factors and stress (Ronkina and Gaestel, 2022). In general, the MAPK signaling pathway can mediate the release of TNF-α, IL-1, IL-6, IL-8, and other inflammatory factors, cell apoptosis, and neutrophil activation, induce the expression of intracellular nitric oxide, improve the activity of intracellular inducible nitric oxide synthase, and induce the occurrence and development of IBD and colon cancer (Yong et al., 2009). In addition, PI3K is a key target that is closely related to inflammation and tumor development. In the inflammatory state, PI3K phosphorylates phosphatidylinositol 4,5-bisphosphate (PIP2) to generate phosphatidylinositol-3,4,5-triphosphate (PIP3), recruiting downstream proteins such as Akt. The activated AKT subsequently phosphorylates multiple downstream substrate proteins. PI3K can also promote the activation of NF-κB and regulate the inflammatory response by phosphorylating and inhibiting IκB kinase (IKK); it can also regulate biological processes such as cell proliferation, survival, apoptosis, and metabolism and then promote tumor progression. Briefly, it can 1) act on mammalian rapamycin target protein complex 1 (mTORC1) to promote protein synthesis and cell growth; 2) phosphorylate forkhead box O (FOXO) transcription factors, inhibit its transcriptional activity, and affect cell cycle, apoptosis, and metabolism; 3) inhibit the activity of glycogen synthase kinase 3 (GSK3) and regulate glycogen synthesis and cell cycle; 4) phosphorylate and activate the pro-apoptotic protein Bad, making it unable to bind to Bcl-2 or Bcl-XL, and thus reducing the occurrence of normal cell apoptosis (Mayer and Arteaga, 2016; Wang et al., 2023e). In the above study, Sishen Pill improved intestinal inflammatory factors, immune cell disorders, and a series of symptoms of IBD by downregulating the expression of key proteins in the MAPK (Zhao et al., 2013) and PI3K/Akt (Ge et al., 2020; Zhang et al., 2021c; Liu et al., 2021; Liu et al., 2022) signaling pathways, and its active metabolites bavachin (Wang et al., 2023a), myristicin (Duan et al., 2020), evodiamine (Chien et al., 2014), schisandrin B (Jiang et al., 2015), 8-methoxypsoralen (Bartnik et al., 2017), and schisandrin B (Dai et al., 2018). Consequently, the Sishen Pill could inhibit the progression of colon cancer by regulating the MAPK and PI3K pathways.

The NLRP3 inflammasome and Wnt signaling pathways affect pyroptosis and cell differentiation/apoptosis, respectively, and are potential targets for regulating colon inflammation-cancer transformation. NLRP3 inflammasome is composed of NLRP3, apoptosis-associated speck-like protein containing CARD (ASC) and effector pro-caspase-1, and can affect the occurrence and development of IBD and even cancer via regulating the maturation, secretion, and pyroptosis of IL-1β and IL-18. Studies found that for IBD patients during the active period, the production of IL-1β and IL-18 and the activity of caspase-1 increase, thereby mediating the occurrence of intestinal cell apoptosis (Qi et al., 2021). Cell apoptosis is an important pathological basis for the transformation from inflammation to cancer and can induce the release of pro-inflammatory cytokines and promote tumor infiltration into local tissues, thus increasing the risk of tumor occurrence and metastasis (He et al., 2024). In addition, the Wnt/β-catenin signaling pathway has been confirmed to influence the differentiation fate of cell development to a certain extent, affecting cancer cell proliferation, stemness, apoptosis, autophagy, and metabolism. The modification and degradation of β -catenin are key events in the occurrence and development of colon cancer (Zhao et al., 2022). The research indicates that Sishen Pills (Zhao et al., 2019) and their active metabolites, schisandrin B (Zhang et al., 2021a), schisandrin (Wang et al., 2023d), evodiamine (Kim et al., 2019; Shen et al., 2019; Ding et al., 2020), and rutaecarpine (Byun et al., 2022) could affect cell fate by regulating the NLRP3 and Wnt signaling pathways, thus offering a therapeutic role in IBD and colon cancer.

Research has shown that during chronic inflammation, innate immune cells such as macrophages produce large amounts of reactive oxygen species (ROS) and reactive nitrogen species (RNS), leading to the aggravation of oxidative stress. During the active phase of IBD, the expression of ROS in the intestinal mucosa increases, and the subsequent reaction of ROS with DNA can lead to chromosomal breakage, carcinogenesis, and tumor cell proliferation (Wu and Liu, 2022). Regulating the Nrf2/HO-1 pathway may be a way to treat IBD with Sishen Pills (Zhang et al., 2021b), involving their active metabolites such as myristicin (Ismail Abo El-Fadl and Mohamed, 2022), linalool (Tekeli et al., 2018), rutaecarpine (Zhang et al., 2020b) and schisandrin B (Zhang et al., 2021a). Under normal physiological conditions, the Nrf2 in cells binds to the kelch-like ECH-associated protein 1 (Keap1) in the cytoplasm and remains in a steady state; when Keap1 receives an oxidative stress signal, it can release Nrf2 and then transfer it to the nucleus and upregulate the expression of downstream antioxidant proteins, such as HO-1 (Ibrahim et al., 2023). At the same time, HO-1 can also block the NF-κB activation and downregulate the transcription of inflammatory factors and chemokines by inhibiting the production of cytokines and ROS (Wang and He, 2022); this may contribute to the treatment of IBD by inhibiting intestinal inflammation-cancer transformation (Lu et al., 2023).

As the α subunit of hypoxia inducible factor-1 (HIF-1), HIF-1α mediates the adaptive response of cells to a hypoxic environment. In general, HIF-1 is activated under cellular hypoxia; it can activate multiple target genes involved in regulating the cellular redox status to reduce ROS generation; it can also regulate the expression levels of mitochondria-specific genes to adapt to hypoxic environments and improve mitochondrial function. As the above studies showed, the anti-colon cancer effects of evodiamine (Huang et al., 2015; Li et al., 2020a) and isoeugenol may be mediated by HIF-1α. The activation of HIF-1α and its signaling pathway has bidirectional regulatory effects. Studies have confirmed that moderate activation can promote cell survival and increase the protective effect against injury stimuli, whereas excessive activation can aggravate damage to intestinal cells (Taylor and Colgan, 2007). Due to the abnormal vascular microenvironment and inadequate local blood and oxygen supply to the tumor, hypoxia is a common feature of colon cancer; HIF-1α in the activated state can supply energy to tumor cells by upregulating glucose transporters and glycolysis related enzymes, helping cells adapt to the hypoxic environment. Previous studies confirmed that regulating aerobic glycolysis is an important factor for Sishen Pill to treat colon cancer (Zhang et al., 2021d; Jiang et al., 2023); whether it is related to HIF-1α remains to be determined. In addition, the activation of HIF-1α can also promote the tumor angiogenesis and metastasis by up regulating the expression of VEGF and MMP. As the above studies showed, several effective metabolites of Sishen Pill, such as psoralen, isoeugenol, and evodiamine, can downregulate the expression of VEGF and MMP proteins (Li et al., 2019a; Feng et al., 2021; Bilgin et al., 2023), thus promoting the apoptosis and having a therapeutic effect in colon cancer (Figure 3A).

Research has shown that impaired autophagy can disrupt the function of intestinal epithelial cells and affect innate and adaptive immune responses, ROS production, and endoplasmic reticulum stress (ERS), ultimately promoting the occurrence or progression of IBD (Alula and Theiss, 2023). Antimicrobial peptides secreted by intestinal Paneth cells are an important component of the intestinal mucus layer; however, owing to autophagy dysfunction, patients would experience decreased secretion of defensins and lysozymes by Paneth cells, leading to a weakened ability of the intestinal mucosa to resist the colonization of bacteria in the gut, hindering bacterial clearance, and damaging the intestinal mucosal barrier (Cray et al., 2021). At the same time, autophagy also participates in the mucus secretion and degradation metabolism of goblet cells, maintaining a stable balance of interactions between the intestinal mucosa and the gut microbiota (Naama et al., 2023). In the pathological environment of IBD, sustained inflammatory stimulation can lead to protein imbalance and abnormal folding in the lumen of the endoplasmic reticulum, exacerbating ERS. Autophagy can reduce the negative effects of ERS by clearing abnormal proteins and damaged organelles. Previous studies found that the Sishen Pill (Yu et al.) and its metabolites, myristicin (Ismail Abo El-Fadl and Mohamed, 2022) and evodiamine (Ding et al., 2020) promote autophagy and exert a positive influence on downregulating intestinal inflammatory responses.

Other studies have shown that dehydrodiisoeugenol (Li et al., 2021a) and evodiamine (Wang et al., 2019b) promote tumor cell apoptosis and exert anti-colon cancer effects by activating autophagy. Current research suggests that autophagy has a dual role in cancer occurrence. Autophagy is a surveillance system in normal cells that removes damaged organelles and aggregated proteins through lysosomes, consequently reducing DNA damage and protecting cells from malignant transformation (Yamazaki et al., 2021). Clinical studies have shown that a lack of autophagy-related proteins such as LC-3II, ATG5, and Beclin 1 can indicate poor prognosis in colon cancer patients (Choi et al., 2014). Autophagy can also provide key nutrients for tumor growth and metabolism and support tumor formation by inhibiting apoptosis (Galluzzi et al., 2015). Autophagy plays different roles in the different stages of malignant tumor development; a deeper exploration of the pharmacological mechanism of inflammation-cancer transformation as a whole is needed (Figure 3B).

The regulatory effects of Sishen Pill on intestinal immune cells are also important for inhibiting the progression of IBD inflammation and its transformation into colon cancer. Taking Tregs as an example, the number of Tregs in the inflammatory mucosa of patients with IBD often shows a compensatory increasing trend, but the degree of increase is insufficient to control mucosal inflammation, leading to a relatively insufficient state (Hovhannisyan et al., 2011). Peripheral blood cell analysis has shown that the number of Tregs decreases, and the number of pro-inflammatory Th17 cells increases in IBD patients (Eastaff-Leung et al., 2010). Animal experiments have shown that the adoptive transfer of Tregs can alleviate enteritis by inhibiting Th1 and Th17 inflammatory responses, further confirming the regulatory effects of Tregs on intestinal inflammation (Boschetti et al., 2017). Multiple studies have shown that Sishen Pill can upregulate Tregs while downregulating the proportion of Th17 cells, thereby inhibiting the progression of IBD (Liu et al., 2016; Wang et al., 2022b; Huang et al., 2022). Schisandrin B upregulates the expression of forkhead box protein P3 (FoxP3) and promotes Treg proliferation and differentiation, regulating the intestinal immunity of IBD (Liu et al., 2015). The possible role of Tregs in treating intestinal tumors has also received widespread attention, but there is still debate over how Tregs affect the occurrence and progression of tumors. Some studies suggest that Tregs can lead to tumor growth and deterioration by inhibiting anti-tumor immune responses (Saito et al., 2016), associated with poor prognosis of the disease; however, further research is needed to investigate the effect of the Sishen Pill on Tregs in colon cancer models.

Memory T cells (Tms) are a crucial part of inflammatory immune responses. Tms can usually be divided into three main groups: central memory T cells (Tcm), effective memory T cells (Tem), and tissue-resident memory T cells (Trm). Zhao et al. found that the specific activation of Tm can prevent the recurrence of Crohn’s disease (Zhao et al., 2020). Two studies found that Sishen Pills can increase the level of Tcm cells and inhibit intestinal inflammatory factors through the PI3K/Akt and JAK/STAT5 pathways (Ge et al., 2020; Wang et al., 2022a). In addition, Tcm has self-renewal and replication capabilities, can recognize tumor antigens, and exerts long-lasting anti-tumor effects (Wang et al., 2020d). However, there is currently no relevant report on the Sishen Pill and its active metabolites in treating colon cancer by regulating Tcm; a deeper understanding of the pharmacological mechanisms is urgently needed.

JAK/STAT is one of the central communication nodes of cell function and is essential for initiating innate immunity, coordinating adaptive immune mechanisms, and regulating inflammatory responses. In intestinal-associated lymphoid tissues, dendritic cells and other antigen-presenting cells initiate antigen-specific immune responses, determining the activation of B cells and the differentiation of initial T helper cells, driven by the cytokine-receptor interaction of JAK-STAT signaling. Furthermore, different subtypes of helper T cells (Th1, Th2, Th9, and Th17) regulate Tregs, macrophages, and dendritic cells, among other immune cells, thereby regulating the intestinal inflammatory response and inhibiting tumor occurrence (Hu et al., 2021). JAK/STAT pathway inhibitors have been used to treat IBD, showing good therapeutic potential in preclinical studies (Salas et al., 2020). As mentioned above, multiple studies have confirmed that Sishen Pill can regulate intestinal cellular immunity by regulating JAK-STAT and the expression of its downstream protein suppressor of cytokine signaling (SOCS), one of the key signaling pathways by which the pill inhibits IBD immune inflammation and inflammation-cancer transformation (Liu et al., 2016; Liu et al., 2020; Wang et al., 2022a; Kang et al., 2022) (Figure 3C).

Research has shown widespread dysbiosis in the gut microbiota of both IBD and colon cancer patients and that Sishen Pill can affect the integrity of the intestinal barrier by regulating the gut microbiota and its metabolites. The decrease of Akkermansia muciniphila (AKK) and the increase of Escherichia-Shigella are significant characteristics of the gut microbiota in IBD population (Morgan et al., 2012; Alam et al., 2016); animal experiments have shown that Akk can promote the production of intestinal mucus, regulate the expression of tight junction proteins, and reduce the expression levels of inflammatory and chemotactic factors in the colon and serum (Bian et al., 2019). In addition, oral administration of inactivated Akk or the outer membrane protein of Akk (Amuc_1100) can also regulate CD8⁺ T cells, improving IBD and preventing the occurrence of CACC (Wang et al., 2020b). Another study suggested that AKK bacteria could enrich M1-like tumor associated macrophages in the colon cancer microenvironment in NLRP3 dependent way, thereby inhibiting tumor formation and development (Fan et al., 2021a). On the contrary, certain types of Escherichia-Shigella can escape host immunity, adhere to and invade intestinal epithelium and macrophages in hosts with genetic susceptibility to IBD, and initiate IBD development (Zangara et al., 2023). Also, the genotoxin produced by Escherichia-Shigella can penetrate the colon cell membrane and migrate to the nucleus, causing DNA double strand breaks, cell cycle arrest, chromosomal aberrations, intestinal epithelial damage, and eventually leading to cancer (Fan et al., 2021b). The above studies show that Sishen Pill can increase the relative abundance of AKK in the intestine (Chen et al., 2020b; Ge et al., 2022; Jin et al., 2023) and its effective metabolites, evodiamine, and corylin, leading to significant inhibition of Escherichia-Shigella the proliferation (Zhu et al., 2021; Wang et al., 2023f) thereby exerting anti-inflammatory and anticancer pharmacological activities.

Some metabolites of the gut microbiota, such as short-chain fatty acids (SCFAs), are also important for developing colitis and tumors. Studies have shown a decreasing trend in intestinal SCFAs in both IBD and colon cancer populations (Wang et al., 2019c; Dalile et al., 2019). As the main source of energy for intestinal epithelial cells, SCFAs not only promote the proliferation and differentiation of intestinal epithelial cells, reduce cell apoptosis, and maintain the mechanical barrier of the intestinal mucosa but also improve the secretion of intestinal mucoproteins, lubricate the intestine, block the adhesion of pathogens to the intestinal mucosa, and inhibit the occurrence of intestinal immune inflammation (Sun et al., 2017). In addition, butyrate in SCFAs has been proven to promote apoptosis and inhibit the proliferation of human colon cancer cells by activating G-protein coupled receptor 109A (GPR109A) (Moniri and Farah, 2021). The above research indicates that while regulating the gut microbiota, Sishen Pill can increase the contents of total SCFAs and butyrate in the intestine, thereby improving the inflammatory microenvironment of the intestine (Wang et al., 2022b).

Gut microbiota can affect the morphology and function of the intestinal barrier through various pathways; the integrity of the intestinal barrier is of great significance for the treatment of IBD and colon cancer. Post et al. detected 28 mucin proteins in the colonic mucosa of UC patients and found that seven mucin proteins, such as mucin 2 (MUC2), were significantly reduced; 30% of UC patients had abnormal permeability of the mucus layer, suggesting that abnormal colonic barrier function promotes the occurrence of UC (van der Post et al., 2019). Rath et al. showed that healing of the intestinal barrier has a high predictive value for the course of patients with remission-phase IBD; predictive ability of intestinal barrier healing might far exceed established or emerging parameters, such as endoscopic and histological remission (Rath et al., 2023). In addition, intestinal barrier damage and microbial translocation can activate chronic inflammation, further promoting the secretion of pro-inflammatory factors by immune cells and accelerating the process of colonic inflammation-cancer transformation (Shalapour and Karin, 2020). Another study found that when the intestinal vascular barrier is damaged, intestinal bacteria are more likely to spread to the liver, promoting the formation of a pre-metastatic niche for “colon-liver” metastasis, thereby promoting the recruitment of metastatic cells (Bertocchi et al., 2021). As mentioned earlier, Sishen Pills (Zhang et al., 2021c), schisandrin B (Li et al., 2019b), schisandrin C (Kim et al., 2022), and corylin (Wang et al., 2023f) can regulate the secretion of intestinal epithelial tight junction proteins and mucin, repair damaged intestinal mucosal barriers and inhibit the progression of IBD (Figure 3D).