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Article

Immunomodulatory Effects of Epilobium angustifolium Extract in DSS-Induced Colitis: Attenuation of Inflammatory and Metabolic Markers in Mice

by
Rositsa Mihaylova
1,*,
Viktoria Elincheva
1,
Reneta Gevrenova
2,
Dimitrina Zheleva-Dimitrova
2,
Georgi Momekov
1 and
Rumyana Simeonova
1,*
1
Department of Pharmacology, Pharmacotherapy and Toxicology, Faculty of Pharmacy, Medical University of Sofia, 1000 Sofia, Bulgaria
2
Department of Pharmacognosy, Faculty of Pharmacy, Medical University of Sofia, 1000 Sofia, Bulgaria
*
Authors to whom correspondence should be addressed.
Immuno 2025, 5(4), 50; https://doi.org/10.3390/immuno5040050
Submission received: 29 August 2025 / Revised: 1 October 2025 / Accepted: 16 October 2025 / Published: 19 October 2025
(This article belongs to the Special Issue Young Scholars’ Developments in Immunology)
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Abstract

The inflammatory and metabolic complexity of colitis necessitates therapies that act on multiple immune pathways. Using serum proteomic profiling, the present study evaluated the systemic immunomodulatory profile of Epilobium angustifolium lyophilized methanol-aqueous extract rich in oenothein B (EAE) in a dextran sulfate sodium (DSS)-induced mouse model of ulcerative colitis in a comparative manner to dexamethasone (DXM). DSS exposure triggered robust inflammatory activation, evidenced by elevated chemokines (CXCL9, CXCL10, CCL11), proinflammatory cytokines (IL-1α, IL-12, PAI-1, RAGE) and metabolic stress mediators (leptin, resistin, FGF-21). Treatment with EAE significantly attenuated this inflammatory profile, notably reducing Th2-skewed chemokines and eosinophil recruitment. In contrast to DXM, EAE uniquely normalized pro-thrombotic and tissue-remodeling markers, including PAI-1 and RAGE, both implicated in intestinal barrier dysfunction and chronic inflammation. Furthermore, EAE demonstrated superior modulation of inflammation-associated growth factors (IGFBP-5, HGF, Flt3L) and adipokines (leptin, resistin), indicating a broader therapeutic scope that includes metabolic dysfunctions. Collectively, our data reveal that EAE exerts a distinct immunoregulatory profile, modulating both innate and adaptive immune pathways while simultaneously addressing metabolic pathologies. These multifaceted actions underscore its promise as a phytotherapeutic candidate for the management of ulcerative colitis and other inflammatory conditions, with potential advantages over conventional steroid treatment.

Graphical Abstract

1. Introduction

Ulcerative colitis (UC) is a chronic, relapsing form of inflammatory bowel disease (IBD) characterized by persistent inflammation of the colonic mucosa, disruption of the epithelial barrier, and dysregulated immune responses [1,2]. As one of the most common forms of IBD, the etiology of UC is multifactorial, involving complex interactions among genetic predisposition, the intestinal microbiota, external environmental factors, and dysregulation of immune pathways [2,3].
Central to the pathogenesis of the disease and its progression is the exaggerated immune response in the gut mucosa with an imbalance between proinflammatory and anti-inflammatory signaling that leads to prolonged mucosal injury, epithelial barrier dysfunction, and systemic inflammation [4,5]. The deviations in the gut–immune axis of most patients often exhibit a Th2-skewed cytokine profile with induced levels of IL-4, IL-5, IL-13, and eosinophil-recruiting chemokines (i.e., CCL11, eotaxin), which facilitate the infiltration of eosinophils into the inflamed mucosa [6,7]. Once in the mucosa, eosinophils release a variety of proinflammatory mediators, including cytokines, growth factors, and granular proteins such as major basic protein (MBP), eosinophil peroxidase (EPO), and eosinophil cationic protein (ECP) [8,9]. These mediators exacerbate local tissue damage by promoting epithelial injury, disrupting tight junctions, and impairing the integrity of the intestinal barrier [10,11]. Beyond their direct cytotoxic effects, eosinophils also contribute to tissue remodeling by secreting extracellular matrix proteins and promoting the activation of fibroblasts, leading to fibrosis. This remodeling is a critical aspect of chronic inflammation and contributes to the development of strictures and other long-term complications in UC [8,12]. Eosinophils also interact with other immune cells, including mast cells, T lymphocytes, and macrophages, further amplifying the inflammatory cascade. The sustained inflammatory environment is further exacerbated by elevated levels of proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-1 (IL-1), and interleukin-12 (IL-12), which promote an inflammatory loop that is difficult to resolve [13,14,15]. The excessive production of these cytokines leads to chronic inflammation, epithelial damage, and, over time, fibrosis and scarring of the intestinal tissue. Conversely, anti-inflammatory cytokines such as IL-10 and IL-1 receptor antagonist (IL-1ra) typically act to limit inflammation, but their expression is often insufficient or delayed in the context of ongoing mucosal injury [16,17].
While the immune system is the triggering factor in UC pathogenesis, other ongoing events, such as metabolic dysfunction and tissue remodeling, also contribute to disease progression. Proteins involved in tissue remodeling, such as periostin and plasminogen activator inhibitor-1 (PAI-1), are often upregulated in response to intestinal injury, driving both inflammation and fibrosis [18]. These proteins play a significant role in regulating the wound-healing response, but their persistent activation can contribute to chronic inflammation and fibrosis, limiting the regeneration of the epithelial barrier. Moreover, recent research has shown that various growth factors and metabolic mediators are implicated in the development of UC. Factors such as hepatocyte growth factor (HGF), insulin-like growth factor-binding protein-3 (IGFBP-3), fibroblast growth factor 21 (FGF-21) and adipokines are involved in tissue repair, inflammation resolution, and metabolic homeostasis. Inflammatory processes in UC are often accompanied by alterations in these growth factors, reflecting the interplay between immune activation and metabolic dysfunction [19,20,21,22]. The regulation of these factors may not only impact disease severity but also influence the systemic effects of UC, such as metabolic disturbances and the development of comorbid conditions like insulin resistance [23].
Conventional treatments for UC, including aminosalicylates, corticosteroids, immunosuppressants, and biologic agents, aim to reduce inflammation and promote mucosal healing [4,24]. However, these therapies often carry risks of adverse effects, limited long-term remission, and immunosuppression. As such, there is increasing interest in natural, multi-targeted phytotherapeutics that can provide effective immune modulation with a more favorable safety profile.
Epilobium angustifolium (fireweed) is a medicinal plant traditionally used in European folk medicine as a natural remedy for gastrointestinal and other inflammatory conditions [25]. Our previous liquid chromatography-high resolution mass spectrometry (LC-HRMS) analyses on E. angustifolium extract revealed the presence of 121 secondary metabolites, including ellagitannins (such as oenothein B, ellagic acid, galloyl-HHDP-hexose, and ellagic acid O-pentoside), flavonoids (including deoxyhexosides and hexuronides of kaempferol and quercetin), and acylquinic acids (such as chlorogenic, neochlorogenic, and 3-p-coumaroylquinic acid) [26,27]. These phytochemicals, particularly flavonoids and ellagitannins, have demonstrated potent antioxidant and anti-inflammatory effects, including modulation of NF-κB signaling [28,29,30]. Recent studies highlight the ulceroprotective properties of oenothein B and ellagic acid, including reducing gastric acid secretion, rebalancing the gut microbiome, and regulating the gut–brain axis [30,31,32]. However, the therapeutic potential of the plant in the setting of colitis remains underexplored.
A previous study of ours demonstrated the ulceroprotective effects of Epilobium angustifolium extract (EAE), mitigating the clinical, biochemical, and histological features of DSS-induced colitis in mice, with effects comparable to those of dexamethasone (DXM) [33]. Building on our previous research, the present study seeks to elucidate the molecular mechanisms underlying the established in vivo ulceroprotective effects of EAE [33], with a particular focus on its impact on the inflammatory pathways, oxidative stress, and tissue remodeling in the context of DSS-induced colitis. Using serum proteome profiling, we aim to provide insights into how targeted modulation of immune–inflammatory crosstalk helps alleviate chronic inflammation and tissue damage characteristic of UC. The therapeutic potential of the Epilobium angustifolium extract was evaluated on a broad array of cytokines, chemokines, and metabolic markers associated with both innate and adaptive immunity and compared to the reference corticosteroid drug DXM. Furthermore, the mechanistic aspects of the studied EAE were discussed in the context of its main secondary metabolites, quantified using ultra-high-performance liquid chromatography with diode array detection (UHPLC-DAD).

2. Materials and Methods

2.1. Plant Material and Plant Extraction

The collection of plant material and sample extraction were previously described [26]. The aerial parts of E. angustifolium L. f. angustifolium were collected in July 2023 from the “Platoto” locality, Vitosha Mountain, Bulgaria. The plant’s taxonomic identity was verified by R. Gevrenova according to the reference [34]. A voucher specimen (No. 11823) was deposited at the Herbarium Facultatis Pharmaceuticae Sophiensis, Medical University-Sofia, Bulgaria. The plant material was dried and extracted with 80% methanol (1:20 w/v) via sonication for 15 min, repeated twice. Following extraction, the methanol was removed in vacuo at 40 °C, and water residues were lyophilized to yield the crude extract (EAE). This lyophilized extract was then used in subsequent analyses.

2.2. Chemicals

The reference standards used for compound identification were obtained from Extrasynthese (Genay, France) for myricitrin, hyperoside, miquelianin, isoquercitrin, isorhamnetin 3-O-glucoside, kaempferol 3-O-glucoside, quercitrin. Gallic, neochlorogenic, and ellagic acids were supplied from Phytolab (Vestenbergsgreuth, Germany). Acetonitrile (hypergrade for LC-MS), formic acid (for LC-MS), and methanol (analytical grade) were purchased from Chromasolv (Sofia, Bulgaria). The DSS was purchased from MP Biomedicals (Toronto, ON, Canada) and is a standardized “Colitis grade,” specifically intended for inducing ulcerative colitis in animal models.

2.3. UHPLC-DAD Analysis

The UHPLC-DAD analyses were performed on a Thermo Scientific Dionex UltiMate 3000 (Thermo Fisher Scientific, San Diego, CA, USA) analytical system equipped with a Dionex UltiMate 3000 RS Pump (LPG-3400RS), Dionex UltiMate 3000 RS Autosampler (WPS-3000TRS), Dionex UltiMate 3000 RS Column Compartment (TCC3000RS) and Dionex UltiMate 3000 Diode Array Detector (DAD-3000). The separation and quantitative analysis were achieved as previously described by Mihaylova et al., 2024 [35,36].

2.4. Animals and Housing Conditions

A total of 27 male ICR mice, weighing between 20 and 30 grams, were housed in Plexiglas cages (six mice per cage) under a 12 h light/dark cycle. Standard laboratory conditions were maintained, with a room temperature of 20 ± 2 °C and relative humidity of 72 ± 4%. The animals were obtained from the National Breeding Center in Sofia, Bulgaria, and were given at least seven days to acclimate before the start of the experiment. They had free access to appropriate food and fresh drinking water throughout the study. All experimental procedures were approved by the Animal Care Ethics Committee at the Bulgarian Food Safety Agency, with ethical clearance No. 346 dated 28.02.2023.

Experimental Design

The mice were randomly assigned to four groups (n = 6 per group):
Group A (Control): Received only standard food and clean drinking water throughout the experiment.
Group B (Colitis Model): DSS-induced colitis, but received no treatment.
Group C (Colitis + Plant Extract): Colitis was induced, and mice were orally treated for 21 days with Epilobium angustifolium extract (EAE) at 300 mg/kg [33].
Group D (Colitis + Dexamethasone): Colitis was induced and treated with dexamethasone (DXM) at a dose of 1 mg/kg [33].
Ulcerative colitis was induced in all experimental groups (except the control group) by adding 3% dextran sulfate sodium (DSS) to the drinking water during the first 7 days of the study [37]. Throughout the experimental period, groups 3 and 4 continued receiving EAE (300 mg/kg) or DXM (1 mg/kg), respectively.
On the 22nd day, following an overnight fast, all animals were anesthetized with ketamine/xylazine (80 mg/10 kg, intraperitoneally) and subsequently euthanized. Blood samples were collected after animal decapitation in vacutainers with a cloth activator for serum preparation.

2.5. In Vitro Proteome Profiling Analysis

Serum samples prepared from each group at the end of the study were pooled and subjected to proteomic profiling using the Proteome Profiler™ Mouse XL Cytokine Array Kit (R&D Systems, Minneapolis, MN, USA), which enables the simultaneous detection of 111 cytokines, chemokines, and acute phase inflammation proteins. Equal volumes of pooled serum from each group were incubated with pre-blocked array membranes containing capture antibodies spotted in duplicate. Following the manufacturer’s protocol, membranes were incubated with a cocktail of biotinylated detection antibodies, followed by streptavidin-HRP and chemiluminescent substrate. Signal detection was performed using a digital imaging system (Azure Biosystems C600, Azure Biosystems Inc., Dublin, CA, USA), and spot intensities were quantified using ImageJ software (version 1.46). Relative protein expression levels were compared across groups, and differences in the expression profile of targeted proteins were expressed graphically using the GraphPad Prism 8 (Version 8.0) software.

3. Results

3.1. UHPLC-DAD Analysis

An UHPLC-DAD method for the quantitative determination of the main compounds in the E. angustifolium was performed. A total of 12 analytes, including two hydroxybenzoic acids gallic acid (1) and ellagic acid (4), an ellagitannin oenothein B (3), a caffeoylquinic acid (2), and eight flavonol glycosides (5–12) were determined in the extract. Based on the UV-spectra and previous LC-HRMS data compound 12 was assigned as kaempferol 3-O-deoxyhexoside [26]. An UHPLC-DAD chromatogram of the E. angustifolium extract is presented in Figure 1. The content of the assayed compounds is revealed in Table 1. Oenothein B (3) was the major compound in the extract, followed by quercetin 3-O-glucuronide (miquelianin) (7), and quercitrin (11).

3.2. Results from the In Vitro Proteome Profiling

To explore the molecular mechanisms contributing to the ulceroprotective activity of the Epilobium extract, we carried out proteome profiling of serum cytokines and chemokines linked to different phases of the inflammatory immune response. Although previous studies have revealed some mechanistic insights into the anti-inflammatory effects of Epilobium preparations rich in oenothein B, pharmacodynamic data at the systemic level remain scarce.
Accordingly, the results presented herein complement our earlier work [33], providing extensive new evidence of the general rather than tissue-specific immunomodulatory and anti-inflammatory activities of the Epilobium angustifolium species. Furthermore, our systemic approach makes a valuable contribution to the molecular characterization of the DSS-induced colitis as a useful inflammatory model for pharmacological evaluation.
In keeping with our previous design, comparative analysis was performed across four experimental groups, as reflected in Figure 2.
As anticipated, DSS administration triggered marked changes in immune signaling, promoting chemotaxis, infiltration, and activation of immune cells, known to facilitate inflammatory and immunological responses to stressful stimuli. Both protective treatments (DSS + EAE, DSS + DXM) effectively alleviated the DSS-induced systemic immune reactions, though to varying extents and with distinct immunomodulatory profiles (Figure 2, Figure 3). For greater clarity and comprehensibility, Figure 3 provides a heatmap representation of the summarized data on the immunomodulatory and anti-inflammatory activity of both treatment regimens (DSS + EAE, DSS + DXM) as compared to the positive control DSS treated group. Conversely, DSS-induced alterations were defined against the healthy naïve control animals (Ko).

3.2.1. Modulation of Serum Chemokine Levels

DSS administration led to a significant upregulation of multiple inflammatory chemokines, reflecting robust immune activation and tissue inflammation. Substantially elevated (2 to 10 times) in the DSS group were the chemokines belonging to the CXC family, namely CXCL9 (MIG), CXCL10 (IP-10), CXCL11 (I-TAC), CXCL16 and CXCL1, as well as the CC family members CCL6, CCL11, CCL12, CCL17, CCL20, CCL22.
The chemokine members of the CXC family (CXCL9, CXCL10, CXCL11, CXCL16, CXCL1) play a crucial role in orchestrating immune responses, particularly those associated with the Th1 phenotype. These chemokines are primarily involved in the recruitment and activation of immune effector cells such as T lymphocytes, natural killer (NK) cells, and neutrophils, thereby contributing to the amplification of cell-mediated immunity and inflammatory processes. CXCL10 and CXCL11, in particular, are potent chemo-attractants for CXCR3+ cells and are often overexpressed in active IBD mucosa, correlating with epithelial damage and immune cell infiltration. The modest suppression of these chemokines by both DXM and EAE suggests shared inhibitory effects on IFN-γ-driven pathways. However, the preferential reduction of CXCL16 by EAE (~30%), which plays a role in neutrophil recruitment and epithelial adhesion, indicates a potential capacity of the extract to more effectively limit neutrophil-driven mucosal injury.
Interestingly, the modulation of Th2-associated CC chemokines (CCL11, CCL17, CCL20), which orchestrate the recruitment of eosinophils and dendritic cells and are implicated in chronic allergic-type and mucosal inflammation, revealed a more pronounced response to EAE. This targeted suppression of Th2-type chemokines by the extract implies its potential to rebalance immune polarization, which is particularly relevant in UC, where Th2-like inflammation is prevalent. Notably, CCL11 (Eotaxin) is a key recruiter of eosinophils, and its robust downregulation by EAE may contribute to attenuated tissue remodeling and fibrosis, often driven by eosinophilic inflammation.
Despite these immunomodulatory effects, CXCL9 and CCL6 levels remained elevated across all DSS-treated groups, highlighting pathways resistant to therapeutic modulation in this model. CXCL9 (MIG), a downstream target of IFN-γ, reflects sustained Th1 inflammation, whereas CCL6, primarily expressed by myeloid cells, may indicate persistent macrophage activation and infiltration. Their resistance to modulation may indicate ongoing myeloid cell infiltration unrestrained by either treatment intervention.
The normalization of Gas6 levels by both treatments is particularly noteworthy. Gas6 functions as a homeostatic modulator that inhibits excessive activation of dendritic cells and macrophages through TAM receptor signaling, promoting immune resolution. Its restoration implies a shared ability of EAE and DXM to restrain antigen-presenting cell (APC) overactivation, which is critical in curbing chronic inflammation and tissue injury in IBD.

3.2.2. Modulation of Inflammation-Related Cytokines and Regulatory Factors

Additional insights into the immuno-inflammatory profile of the animals across the treatment groups provide the observed changes in the expression levels of both proinflammatory (LIF, IL-12/p40, IL-1α, Periostin, PAI-1, Tissue factor, M-CSF, PEDF, Complement factor D, PAGE, CD14, Osteoprotegerin) and anti-inflammatory (IL-10, IL-1ra) factors.
The most prominent upregulation in the DSS-induced colitis model was observed for plasminogen activator inhibitor-1 (PAI-1) and the receptor for advanced glycation end products (RAGE), both of which exhibited nearly 3-fold increases. This pronounced induction likely reflects the underlying proinflammatory and prothrombotic environment triggered by DSS exposure. PAI-1 is a known downstream target of IL-6 and TNF-α signaling and plays a pivotal role in suppressing fibrinolysis, thereby contributing to a hypofibrinolytic, thrombogenic state frequently associated with intestinal inflammation. PAI-1 and its target, tissue plasminogen activator (tPA), play key roles in regulating intestinal inflammation. tPA, produced by intestinal epithelial cells, protects against colonic injury induced by chemical and mechanical stress. In contrast, PAI-1 exacerbates mucosal damage by inhibiting tPA-mediated activation of the anti-inflammatory cytokine TGF-β. Inhibition of PAI-1 reduces both mucosal damage and inflammation. Additionally, PAI-1 has been linked to insulin resistance and metabolic dysfunction, highlighting its broader impact on pathology and health. RAGE, on the other hand, responds to the accumulation of advanced glycation end products and other ligands common in chronic inflammation, promoting sustained NF-κB activation and propagation of inflammatory signaling. Notably, EAE treatment significantly reduced the expression of both PAI-1 and RAGE by approximately 2-fold, an effect not achieved by DXM, suggesting that EAE may engage anti-inflammatory and anti-thrombotic pathways beyond the range of glucocorticoid actions.
This regulatory pattern extended to several other inflammatory markers, including IL-12, IL-1α, periostin, tissue factor (TF), and pigment epithelium-derived factor (PEDF), all of which were markedly elevated (2- to 3-fold) in response to DSS treatment. EAE consistently reduced the levels of these proteins more effectively than DXM, indicating a broader anti-inflammatory capacity. Notably, DXM not only failed to restrain but paradoxically induced the production of the potent inflammatory mediator IL-1α, reflecting a certain limitation in cytokine control in this particular model.
EAE treatment prompted a mild, however notable decline in periostin’s levels, which is of particular importance, as this protein plays a critical role in tissue remodeling and chronic inflammation in various diseases of eosinophilic type, further supporting the Th2-targeted effects of the extract. This finding may be of particular relevance in the context of IBD pathogenesis, as periostin has been implicated in inflammation through the activation of NF-kB signaling.
The pigment epithelium-derived factor (PEDF), on the other hand, is an endogenous anti-inflammatory factor known as a negative regulator of NF-κB signaling. In our study, it appeared to be exclusively attenuated in response to phytotherapy but not to DXM, suggesting an upstream modulatory activity of the Epilobium extract on cytokine production, and its favorable role in maintaining epithelial integrity and resolving inflammation.
IL-12, a central cytokine bridging innate and adaptive immunity in Th1 mediated autoimmune diseases, was strongly induced in the DSS model but partially reversed (by ~50%) in response to EAE treatment. DXM, however, had a negligible impact, further distinguishing the immunomodulatory profile of the two agents.
In line with the procoagulant shift observed with PAI-1, tissue factor (TF) was also elevated over two-fold in DSS-treated animals, reflecting its dual role in coagulation and inflammation. TF is a key initiator of the extrinsic coagulation cascade and a known contributor to inflammation-driven thrombogenicity and is often upregulated in response to mucosal injury and inflammatory stimuli. In concert with PAI-1, the pronounced induction of TF under DSS exposure is also indicative of a heightened procoagulant and pro-inflammatory state within the colonic microenvironment. Notably, the elevation of these proteins was more effectively attenuated by EAE, underscoring its capacity to modulate both the inflammatory and prothrombotic aspects of IBD.
In contrast to its weaker regulation of proinflammatory cytokines, DXM showed superior inhibition of CD14 and Complement Factor D, both of which are critical components of innate immune activation and amplification via the alternative complement pathway. These findings are consistent with DXM’s well-known immunosuppressive efficacy, particularly in restraining monocyte and macrophage activation. Interestingly, M-CSF, a growth factor essential for monocyte proliferation and differentiation, was similarly downregulated by both EAE and DXM, suggesting that both agents converge in their capacity to limit monocyte-driven inflammation.
In contrast, IL-10 and LIF (Leukemia inhibitory factor), which serve protective, anti-inflammatory and immunoregulatory functions during early inflammation, remained largely unaffected by either treatment regimens, indicating the limited capacity of both EAE and DXM to modulate these cytokines once colitis is established. These results could suggest that EAE and DXM exert their effects downstream of their production and are more likely to restrain the acute phase of the DSS-induced inflammatory response. However, the Epilobium extract was found to produce a moderate decline in the serum concentrations of IL-1ra, acting as a natural inhibitor of IL-1α and IL-1β signaling, potentially reflecting an effective upstream suppression of immune and inflammatory responses leading to its secretion.
Finally, the nearly 2-fold induction of osteoprotegerin (OPG), a member of the TNF family, remained unaltered in both treatment modes of protection. Beyond bone health, OPG is increasingly recognized as a key player and a reliable marker in various chronic inflammatory conditions, including gut inflammation. In this context, its compensatory induction has been shown to serve a regulatory function in restoring immune homeostasis and limiting inflammation. The sustained elevation of OPG across all DSS-treated groups may reflect an ongoing response to the colitis-related tissue damage, that was not weakened by neither EAE nor DXM.

3.2.3. Modulation of Inflammation-Related Growth Factors and Hormones

Inflammation-related growth factors and metabolic mediators also revealed distinct changes in a treatment-specific pattern.
A nearly 50% rise was measured in the plasma concentration of IGFBP-3, a potent negative regulator of inflammation, attesting the onset of active colitis. IGFBP-3 facilitates both IGF-dependent and independent mechanisms, limiting the pro-survival effects of growth factors of the IGF family, while also exerting direct anti-inflammatory activity by suppressing NF-κB signaling and reducing cytokine production. In colitis and other inflammatory conditions, IGFBP-3 has been associated with enhanced epithelial barrier function and tissue repair, suggesting a protective role in maintaining mucosal integrity and controlling immune responses. However, in both groups of DSS- and EAE-treated animals, no change in its levels was reported, implying a constitutive adaptation to the inflammatory insult induced by DSS.
On the other hand, effectively attenuated by DXM and especially by the Epilobium extract was the induction of another member of the GFBP family, namely IGFB-5. As opposed to other IGFBPs, including IGFBP-3, the role of IGFBP-5 appears to be pro-inflammatory and pro-fibrotic, and its upregulation in the DSS-induced model of colitis may signal a shift from acute inflammation toward pathological tissue remodeling, which was notably prevented by the EAE.
A striking DSS-induced elevation (~3-fold) was observed in the stress-inducible hepatokine FGF-21, which has been shown to reflect the severity of inflammation, nutritional and microbiome status in IBD and other inflammatory diseases of the digestive system. While both treatments reduced its expression, EAE restored FGF-21 to near-control levels, suggesting superior efficacy in resolving inflammatory metabolic dysfunction.
The Hepatocyte Growth Factor (HGF) also underwent a nearly 3-fold increase in our model of colitis. HGF is a pleiotropic cytokine with diverse biological functions and has been recognized as a crucial mediator in tissue development, repair, regeneration and immune regulation in various inflammatory and autoimmune diseases, including IBD. The observed in vivo induction of this factor is most likely a physiological counter reaction to protect tissues from injury, limit inflammation and promote healing. In the two groups of co-treated animals, EAE lowered HGF levels somewhat more effectively, indicating a reduction in the acute inflammatory response.
Another stress-responsive cytokine substantially upregulated upon DSS exposure was Growth and differentiation factor 15, formerly known as NSAID-activated gene 1 (NAG-1) and Macrophage Inhibitory Cytokine-1 (MIC-1). Similarly, to IGFBP-3 and HGF, GDF-15 acts as a negative feedback regulator in various pathological conditions with underlying immune–inflammatory components, promoting immune tolerance and survival under stressful stimuli. Once again, only in the EAE-treated animal group did GDF-15 levels return to those of the untreated control, implying the mitigating effect of the extract on DSS-induced acute-phase inflammation.
Compared to the naïve control animals, the DSS treated group also exhibited twice-higher circulating levels of Fms-like tyrosine kinase 3 ligand (Flt3L), which is essential for the differentiation, proliferation, and survival of dendritic cells (DCs). During inflammation, elevated Flt3L levels promote DC expansion and enhance T cell activation needed for antigen presentation and initiation of the adaptive immune responses. Therefore, Flt3L has been found to be overexpressed in the settings of various infectious diseases but has also been implicated in the pathogenesis of inflammatory diseases like systemic lupus erythematosus and rheumatoid arthritis. Notably, other studies have also demonstrated the participation of this growth factor in shaping the inflammatory response in animal models with DSS-induced colitis. In our study, the Epilobium extract demonstrated superior efficacy in restoring Flt3L levels to baseline (control) values, whereas DXM failed to produce a similar effect.
Finally, notable alterations were observed in the levels of the adipokines leptin and resistin, both of which are increasingly recognized for their roles in linking metabolic regulation with inflammation. Leptin is a hormone primarily involved in energy homeostasis and appetite suppression, however its excessive production in obese patients has been found to sustain a chronic low-grade inflammatory state, promote insulin resistance, atherosclerosis and other hallmark traits of metabolic syndrome. The activation of its long-form receptor (Ob-Rb) on immune cells such as macrophages, dendritic cells, and T lymphocytes triggers the JAK2/STAT3, MAPK, and PI3K signaling pathways, induces COX2 expression and stimulates the production of pro-inflammatory cytokines, including TNF-α, IL-6, and IL-12. In our colitis model, leptin levels were elevated approximately three-fold, consistent with its known role in inflammatory conditions. Noteworthy was that the Epilobium extract appeared to be more effective in attenuating this rise, bringing leptin concentrations close to baseline levels, whereas DXM produced a partial effect. Resistin, another adipokine implicated in chronic inflammation and insulin resistance, was nearly doubled in response to DSS treatment, contributing to both local and systemic inflammatory responses. Both EAE and DXM treatments led to comparable reductions in resistin levels, although to a lesser extent compared to leptin. The observed ability of Epilobium angustifolium extract to significantly decline both adipokines levels assert its therapeutic potential as a natural remedy mitigating metabolic dysfunction.

4. Discussion

The immunomodulatory effects of the Epilobium angustifolium extract in the DSS-induced colitis model, as revealed by our proteome profiling, can likely be attributed to its diverse chemical composition and the synergistic interactions of its dominant constituents. The major bioactive compounds identified in the extract (ellagitannins, flavonoids and acylquinic acids) each possess diverse biological properties and are likely to play complementary roles in the molecular resolution of immune inflammation.
Ellagitannins, including oenothein B and ellagic acid, are hydrolyzable tannins well known for their potent anti-oxidant, anti-inflammatory, and immunomodulatory properties [31,32]. Both phytochemicals are metabolized by the gut microbiota into urolithins, which are readily absorbed into the circulatory system [30], further supporting the EAE’s potential to alleviate both local and systemic inflammation. Flavonoids, particularly kaempferol and quercetin, are well-known for their anti-inflammatory and antioxidant properties. In Epilobium angustifolium, these flavonoids exist as deoxyhexosides and hexuronides, compounds that have been reported to influence immune cell signaling and modulate inflammation through several pathways.
In particular, oenothein B is the most dominant component found in Epilobium angustifolium and has shown significant efficacy in modulating immune responses. Previous studies on oenothein B provide some mechanistic context for our findings. Interestingly, oenothein B has been shown to modulate chemokine biology in vivo in a context-dependent manner. For instance, it has been found to induce CXCL1 and keratinocyte chemoattractant (KC) production and promote neutrophil recruitment after intraperitoneal administration in mice. The same study on the immunomodulatory effects of an Epilobium extract also reported a time-dependent induction of NF-κB and phagocyte functions (Ca2+ flux, ROS, chemotaxis), produced exclusively by the oenothein B-rich subfraction of the extract [38]. Nevertheless, independent studies have demonstrated that oenothein B can suppress key NF-κB-regulated mediators (including iNOS, IL-1β, IL-6, and TNF) upon TLR2/4 activation, providing a mechanistic basis for its capacity to attenuate downstream chemokine signaling [39,40]. Such bias activity suggests context-dependent regulation, consistent with the selective suppression of CXCL and CC family members observed here.
Notably, in other models of DSS-induced colitis, the flavonoid polyphenol quercetin improved colonic histology, decreased inflammatory cell infiltration, and enhanced the expression of tight junction proteins, thereby strengthening mucosal barrier integrity. Consistent with our findings on EAE treatment, transcriptomic analyses have identified the CXCL8–CXCR1/2 axis as a key target of quercetin’s activity, with pronounced downregulation of these chemokines and their receptors in quercetin treated animals [41].
The effects of oenothein B on the activation of human dendritic cells (DCs) induced by LPS or cytokines have been investigated in vitro. Oenothein B significantly inhibited the expression of key markers involved in DC-T cell interactions, including CD40, CD80, CD83, and CD86. Additionally, it suppressed the release of potent proinflammatory cytokines such as IL-12p40 and IL-6, which are crucial for Th1 polarization [42]. At the systemic level, oenothein B has been found to significantly mitigate alcohol-induced liver damage, as indicated by reduced serum aminotransferase levels, lower inflammatory biomarker expression, and enhanced antioxidant defenses in treated groups. Its hepatoprotective effects have been attributed to attenuating oxidative stress through activation of the Keap1/Nrf2 signaling pathway and suppressing inflammation via downregulation of the TLR4/NF-κB axis. Furthermore, oenothein B favorably modulated alcohol-induced gut dysbiosis, improving both the structure and composition of the intestinal microbiota [43]. Building on these findings, we demonstrate that the oenothein B-rich EAE also targets the HGF-MET axis, further elucidating the molecular basis of its anti-inflammatory and tissue-protective actions.
In the context of intestinal inflammation, several preclinical studies demonstrate the therapeutic potential of ellagic acid in ulcerative colitis. In various DSS-induced mouse models, it significantly alleviated intestinal inflammation, oxidative stress, and epithelial damage. These protective effects were linked to suppression of the ROS/NLRP3 inflammasome axis and activation of the Nrf2 antioxidant pathway, as well as inhibition of key inflammatory signaling cascades including NF-κB, MAPK, and STAT3. Notably, ellagic acid also modulated gut microbiota composition, reversing DSS-induced dysbiosis. In chronic ulcerative colitis models, ellagic acid more robustly reduced histological scores and inflammatory mediators (TNF-α, IL-6, IFN-γ), while downregulating COX-2 and iNOS expression. Moreover, its systemic protective effects extended to liver and brain tissues via modulation of the gut–liver–brain axis [44,45,46]. These findings align with our results and highlight EAE’s ability to alleviate both local and systemic inflammation through immunomodulatory, antioxidant, and microbiota-regulating mechanisms.
In our DSS-induced colitis model, we observed selective downregulation of the pro-inflammatory factors IL-1α and IL-12/p40 by EAE, which is mechanistically supported by known actions of both oenothein B and the dominant flavonoids in our extract-kaempferol and quercetin. Both polyphenols have been found to modulate the NF-κB and MAPK signaling pathways and inhibit the downstream secretion of the cytokines [47]. Kaempferol, a flavonoid prevalent in various fruits and vegetables, has demonstrated significant anti-inflammatory effects in models of ulcerative colitis. In a study involving DSS-induced colitis in mice, kaempferol administration improved clinical symptoms such as weight loss, diarrhea and colon shortening. Histopathological analysis revealed reduced colonic inflammation and preservation of mucosal epithelium. Notably, it has been shown to enhance the expression of tight junction proteins, including ZO-1, occludin, and claudin-1, thereby restoring intestinal barrier integrity. At the cellular and molecular level, kaempferol inhibited the TLR4-NF-κB signaling pathway, leading to decreased expression of pro-inflammatory cytokines such as IL-1β, IL-6, and TNF-α, and an increase in the anti-inflammatory cytokine IL-10. Additionally, kaempferol modulated the gut microbiota by increasing beneficial bacteria like Prevotellaceae and Ruminococcaceae, while decreasing harmful Proteobacteria [48,49]. Similarly, in models of monosodium glutamate (MSG)-induced immune stress, quercetin reduced IL-1β, IL-6, IL-8, and TNF-α levels through NF-κB and JAK/STAT pathway inhibition, while promoting an anti-inflammatory response via IL-10 upregulation and PPAR-γ/LXRα activation [50]. It also mitigated oxidative stress and inflammation by enhancing antioxidant defense and suppressing RIPK3-mediated pathways. Furthermore, in leptin-induced endothelial inflammation, quercetin attenuated ERK1/2 phosphorylation, NF-κB activation, and TNF-α secretion, highlighting its role in countering obesity-related inflammatory damage [50].
Another major polyphenol in the Epilobium extract, namely gallic acid, has been shown to decrease the pro-inflammatory cytokines IL-1/6, TGF-β and TNF-α, as well as stimulate the release of anti-inflammatory cytokines IL-4/10 by inhibiting the IκB/NF-κB pathway [51]. It has also been demonstrated to reverse 1, 2-dimethylhydrazine-induced ulcerative colitis by suppressing NF-κB signaling pathway, causing the decline of pro-inflammatory factors COX-2 and iNOS [52]. Furthermore, some metabolites of acylquinic acids (dihydrocaffeic acid, ferulic acid and their sulfates and glucuronides) may have anti-inflammatory activity. For instance, dihydrocaffeic acid significantly reduced secretion of the proinflammatory cytokines TNF-α, IL-1b and IL-6 [53].
However, the most dramatic induction in serum levels (nearly 3-fold) in response to DSS treatment was established for the PAI-1 and RAGE factors, linking local intestinal injury to systemic proinflammatory and prothrombotic responses. Unlike DXM, EAE effectively halved the overexpression of both proteins, which may be attributed to the potent regulatory effects of its principal components. Quercetin has been shown to downregulate PAI-1 transcription by enhancing the binding of upstream stimulatory factor-2 to specific sequences within the PAI-1 promoter, resulting in a ca. 50% reduction in its secretion by human coronary artery endothelial cells [54]. This observation aligns with our findings that EAE reduces PAI-1 expression more effectively than DXM, suggesting that quercetin within the extract may contribute to disrupting the pro-thrombotic cascade through transcriptional regulation. Similarly attenuated in the EAE treated group was RAGE, a central amplifier of chronic inflammatory signaling promoting sustained NF-κB activation. Quercetin again emerges as a likely mediator of this effect: in pancreatic cancer models, it markedly inhibited RAGE expression, leading to enhanced cell death, autophagy, and restored drug sensitivity [55].
In support of our findings, evidence from related Epilobium species with overlapping phytochemical profiles further highlights the therapeutic promise of this genus in inflammatory conditions. For instance, preclinical studies also suggest that Epilobium angustifolium extracts, particularly those rich in oenothein B, support prostate health through multifaceted mechanisms, including androgen regulation, inhibition of prostate-specific antigen synthesis and anti-proliferative and pro-apoptotic effects. In a testosterone propionate-induced rat model of benign prostatic hyperplasia (BPH), the extract reduced androgen levels, suppressed NF-κB activation, and attenuated inflammation and oxidative stress. Additionally, E. angustifolium has been shown to inhibit metalloproteinases such as neprilysin, ACE, and aminopeptidase N-enzymes implicated in BPH pathogenesis. Clinical relevance of these therapeutic effects has been further supported by a couple of randomized, placebo-controlled phase II trials demonstrating that preparations containing E. angustifolium significantly improved lower urinary tract symptoms and reduced nocturia in BPH patients [56,57].
It is also noteworthy that the major constituents of EAE, namely ellagitannins and flavonoids, have been reported to beneficially influence metabolic health by modulating key growth factors and hormonal pathways involved in inflammation, immune regulation, and energy homeostasis. The molecular mechanisms underlying these effects appear to involve the activation of the AMP-activated protein kinase (AMPK), a central metabolic sensor that enhances glucose uptake, improves lipid metabolism, reduces leptin secretion and suppresses pro-inflammatory signaling. Consequentially, the down-stream activation of peroxisome proliferator-activated receptors (PPARs) contributes to improved insulin sensitivity, fatty acid oxidation and the resolution of chronic low-grade inflammation, which is a hallmark of metabolic syndrome. These regulatory effects on the AMPK-PPAR axis corroborate our findings and further support the therapeutic potential of EAE in the context of metabolic inflammatory disorders.
Quercetin has been reported to improve impaired insulin-mediated glucose uptake under inflammatory conditions by activating AMPK [58]. Similarly, miquelianin (quercetin-3-O-glucuronide, a flavonoid identified in Epilobium angustifolium species), has been shown to exhibit immunomodulatory and anti-inflammatory activity and ameliorate insulin resistance in skeletal cells under inflammatory conditions [39]. More recently, Biyabani et al. demonstrated that quercetin and calorie restriction improved insulin resistance, reduced leptin levels, and ameliorated oxidative stress and steatohepatitis in obese mice [59]. Another in vivo study revealed a dose-dependent preservative effect of quercetin treatment in NAFLD rats, reducing levels of inflammatory cytokines, improving lipid peroxidation, and normalizing serum resistin levels [60]. Other research data indicate the inhibiting effect of quercetin on hepatic cells migration induced by hepatocyte growth factor (HGF) or transforming growth factor-α (TGF-α) through the attenuation of the AKT signaling pathway [61]. Kaempferol has also shown promise in alleviating insulin resistance in various preclinical models by improving insulin sensitivity, promoting glucose uptake, restoring the activity of key enzymes in glucose metabolism and reducing inflammation in adipose tissue [62,63,64].
Another study highlights the potential of ellagic acid as a therapeutic agent for combating obesity and related metabolic disorders. The results indicate that ellagic acid supplementation in high-fat diet-induced obese rats mitigates the typical outcomes of obesity, such as glucose intolerance, increased adiposity, and hepatic steatosis. Notably, it promoted a phenotypic switch in white adipose tissue toward a brown-like state by upregulating key brown adipocyte markers (UCP1, PRDM16, PGC1α, and PPAR-α), while concurrently suppressing white fat genes, thereby improving overall metabolic health. Further supporting our findings, ellagic acid supplementation has been shown to reduce serum resistin levels and improve the lipid profile, contributing to the therapeutic potential of the Epilobium extract in obesity-related co-morbidities [65].
Oenothein B has also been found to inhibit fat accumulation in C. elegans, demonstrating significant antioxidant activity by reducing ROS and enhancing antioxidant enzymes like SOD and GSH-Px. It also modulates lipid metabolism by altering the expression of genes involved in fatty acid synthesis, β-oxidation, and storage, such as mdt-15, fat-5, and fasn-1, further validating EAE’s promise as a potential therapeutic for obesity and related metabolic disorders [66].
Ultimately, our findings outline the therapeutic potential of the Epilobium angustifolium extract in IBD by demonstrating its capacity to modulate key inflammatory, immune, and metabolic pathways. The extract’s multifaceted actions are positively attributable to its phytochemical composition, targeting both local intestinal inflammation and systemic immune-metabolic disturbances. Through synergistic interactions of its dominant constituents, including oenothein B, ellagic acid, quercetin, and kaempferol, EAE exerts anti-inflammatory, antioxidant, anti-thrombotic, and microbiota-modulating properties that complement or exceed the effects of standard glucocorticoid therapy. Our results highlight EAE not only as a promising adjunct or alternative approach in the management of colitis but also as a candidate for broader applications in chronic inflammatory and metabolic disorders.

5. Conclusions

The conducted proteomic analysis provides a comprehensive molecular characterization of the DSS-induced colitis model, revealing key inflammatory and metabolic signatures associated with disease progression. According to our study, the Epilobium angustifolium extract and dexamethasone exhibited distinct immunomodulatory profiles, with EAE preferentially suppressing Th2-associated chemokines and mediators of tissue remodeling and metabolic dysfunction, while DXM exerted broader suppression of Th1-driven inflammation. Importantly, this study offers systemic-level evidence of EAE’s anti-inflammatory activity, extending previous in vivo findings and demonstrating that its effects are not confined to local tissue responses. A central objective and novelty of the present work was to define the distinct immunological responses at the systemic proteomic level, thereby advancing our understanding of both the therapeutic action of EAE and the molecular landscape of DSS-induced colitis. Our results suggest that EAE may provide a more targeted and physiologically balanced alternative to glucocorticoid therapy, particularly in settings characterized by Th2 dominance, metabolic dysfunction, or steroid resistance.

Author Contributions

Conceptualization, R.M. and R.S.; methodology, R.M. and V.E.; software, R.M.; validation, R.M., R.G. and D.Z.-D.; formal analysis, R.M.; investigation, R.M.; resources, D.Z.-D.; data curation, R.M.; writing—original draft preparation, R.M. and V.E.; writing—review and editing, R.M.; visualization, R.M.; supervision, R.M.; project administration, D.Z.-D.; funding acquisition, G.M. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the European Union-NextGenerationEU through the National Recovery and Resilience Plan of the Republic of Bulgaria, project BG-RRP-2.004-0004-C01, “Strategic research and innovation program for development of Medical University—Sofia”.

Institutional Review Board Statement

The animal study protocol was approved by the Ethics Committee of Bulgarian Agency of Food Safety (protocol code 346) on 28 February 2023.

Informed Consent Statement

Not applicable.

Data Availability Statement

The original contributions presented in the study are included in the article.

Conflicts of Interest

The authors declare no conflicts of interest.

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Figure 1. UHPLC-DAD chromatograms of E. angustifolium extract; wavelengths: 360 nm, 310 nm, 280 nm (peaks assignments are listed in Table 1).
Figure 1. UHPLC-DAD chromatograms of E. angustifolium extract; wavelengths: 360 nm, 310 nm, 280 nm (peaks assignments are listed in Table 1).
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Figure 2. Differential expressions of inflammation-related cytokines and chemokines in DSS-induced colitis mice treated with: EAE (C) and Dexamethasone (D), as compared to naïve healthy control (A) and DSS exposed positive control group (B). Determined by membrane-based sandwich immunoassays, where array spots were measured densitometrically. Legend: 1: CXCL9/MIG; 2: IGFBP-3; 3: IL-10; 4: Leptin; 5: CCL6/C10; 6: CXCL10/IP-10; 7: FGF-21; 8: IGFBP-5; 9: LIF; 10: CCL11/Eotaxin; 11: CXCL11/I-TAC; 12: Flt-3L; 13: IL-12/p40; 14: CCL12/MCP-5; 15: Gas 6; 16: IL-1α; 17: Periostin/OSF-2; 18: Serpin E1/PAI-1; 19: CCL17/TARC; 20: Coagulation Factor III/Tissue Factor; 21: CXCL16; 22: M-CSF; 23: Serpin F1/PEDF; 24: GDF-15; 25: IL-1ra; 26: CCL20/MIP-3α; 27: Complement Factor D; 28: HGF; 29: RAGE; 30: CCL22/MDC; 31: CD14 monocytes macrophages; 32: CXCL1/KC; 33: Osteoprotegerin/TNFRSF11B; 34: Resistin.
Figure 2. Differential expressions of inflammation-related cytokines and chemokines in DSS-induced colitis mice treated with: EAE (C) and Dexamethasone (D), as compared to naïve healthy control (A) and DSS exposed positive control group (B). Determined by membrane-based sandwich immunoassays, where array spots were measured densitometrically. Legend: 1: CXCL9/MIG; 2: IGFBP-3; 3: IL-10; 4: Leptin; 5: CCL6/C10; 6: CXCL10/IP-10; 7: FGF-21; 8: IGFBP-5; 9: LIF; 10: CCL11/Eotaxin; 11: CXCL11/I-TAC; 12: Flt-3L; 13: IL-12/p40; 14: CCL12/MCP-5; 15: Gas 6; 16: IL-1α; 17: Periostin/OSF-2; 18: Serpin E1/PAI-1; 19: CCL17/TARC; 20: Coagulation Factor III/Tissue Factor; 21: CXCL16; 22: M-CSF; 23: Serpin F1/PEDF; 24: GDF-15; 25: IL-1ra; 26: CCL20/MIP-3α; 27: Complement Factor D; 28: HGF; 29: RAGE; 30: CCL22/MDC; 31: CD14 monocytes macrophages; 32: CXCL1/KC; 33: Osteoprotegerin/TNFRSF11B; 34: Resistin.
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Figure 3. Heatmap, illustrating the percentage changes in serum levels of all measured target proteins across experimental groups. Color gradients provide a visual representation of up- or down-regulation compared to control and DSS groups. HPC: higher than positive control (DSS).
Figure 3. Heatmap, illustrating the percentage changes in serum levels of all measured target proteins across experimental groups. Color gradients provide a visual representation of up- or down-regulation compared to control and DSS groups. HPC: higher than positive control (DSS).
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Table 1. Content (mg/g dry extract) of compounds assayed in E. angustifolium extract.
Table 1. Content (mg/g dry extract) of compounds assayed in E. angustifolium extract.
NoAnalytetRContent
(mg/g de)
1gallic acid1.50.65 ± 0.05
2neochlorogenic acid3.972.38 ± 0.47
3oenothein B6.8663.60 ± 5.47
4ellagic acid13.522.23 ± 0.10
5myricitrin13.920.69 ± 0.003
6hyperoside14.142.20 ± 0.14
7miquelianin14.3410.77 ± 0.87
8isoquercitrin14.480.24 ± 0.04
9isorhamnetin 3-O-glucoside15.350.90 ± 0.09
10kaempferol 3-O-glucoside16.042.99 ± 0.21
11quercitrin16.147.27 ± 0.80
12Fl 1 (kaempferol 3-O-deoxyhexoside)17.985.83 ± 0.53
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Mihaylova, R.; Elincheva, V.; Gevrenova, R.; Zheleva-Dimitrova, D.; Momekov, G.; Simeonova, R. Immunomodulatory Effects of Epilobium angustifolium Extract in DSS-Induced Colitis: Attenuation of Inflammatory and Metabolic Markers in Mice. Immuno 2025, 5, 50. https://doi.org/10.3390/immuno5040050

AMA Style

Mihaylova R, Elincheva V, Gevrenova R, Zheleva-Dimitrova D, Momekov G, Simeonova R. Immunomodulatory Effects of Epilobium angustifolium Extract in DSS-Induced Colitis: Attenuation of Inflammatory and Metabolic Markers in Mice. Immuno. 2025; 5(4):50. https://doi.org/10.3390/immuno5040050

Chicago/Turabian Style

Mihaylova, Rositsa, Viktoria Elincheva, Reneta Gevrenova, Dimitrina Zheleva-Dimitrova, Georgi Momekov, and Rumyana Simeonova. 2025. "Immunomodulatory Effects of Epilobium angustifolium Extract in DSS-Induced Colitis: Attenuation of Inflammatory and Metabolic Markers in Mice" Immuno 5, no. 4: 50. https://doi.org/10.3390/immuno5040050

APA Style

Mihaylova, R., Elincheva, V., Gevrenova, R., Zheleva-Dimitrova, D., Momekov, G., & Simeonova, R. (2025). Immunomodulatory Effects of Epilobium angustifolium Extract in DSS-Induced Colitis: Attenuation of Inflammatory and Metabolic Markers in Mice. Immuno, 5(4), 50. https://doi.org/10.3390/immuno5040050

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