Atriplex portulacoides L. derived phytochemicals mitigate acetic acid induced colitis in rats via orchestrating Nrf2/Keap1 signalling and LncRNAs gene expression.

Researchers have found that an extract from the sea purslane plant (Atriplex portulacoides) helps treat ulcerative colitis in rats. The study shows that this extract works by reducing inflammation, fighting oxidative stress, and regulating specific long non-coding RNAs (lncRNAs)—molecules that act like master switches to control gut health.

The limits of current colitis therapies

Ulcerative colitis (UC) is a subset of inflammatory bowel disease (IBD). It is characterized by chronic inflammation and damage to the intestinal mucosa (the inner lining of the gut). Current pharmacological treatments often struggle with a significant efficacy gap. Approximately 30% of patients do not respond to anti-TNF$\alpha$ therapy. Many initial responders eventually lose therapeutic efficacy. Furthermore, existing drugs carry heavy trade-offs. These include increased risks of infection and malignancy (cancer).

The fundamental challenge in treating UC lies in a complex interplay of factors. These include genetic susceptibility, environmental triggers, and gut microbiota (the community of microbes in the gut) dysregulation. When this balance shifts, the immune system launches an exaggerated response. This causes oxidative stress. This is a state where reactive oxygen species (ROS) damage lipids, proteins, and DNA within intestinal cells. Most current interventions focus on suppressing specific cytokines (signaling proteins). However, they often fail to address the underlying redox (reduction-oxidation) imbalance and the epigenetic regulators that sustain inflammation.

Orchestrating the Nrf2/Keap1 and lncRNA pathways

The authors propose that the Atriplex portulacoides methanolic extract (APME) acts through a multi-layered regulatory mechanism. Instead of merely blocking a symptom, the extract appears to recalibrate the cell's internal defense systems.

The mechanism follows a coordinated sequence:

1. Activation of Redox Defense: The extract targets the Nrf2/Keap1 signaling pathway. In a healthy state, Keap1 acts as an inhibitor. It keeps Nrf2 (a master transcription factor for antioxidant responses) inactive. The study suggests APME helps overcome this inhibition. This allows Nrf2 to move into the nucleus and trigger protective genes like HO-1 (heme oxygenase-1).
2. Suppression of Pro-inflammatory Signaling: Simultaneously, the extract suppresses the NF-$\kappa$B pathway. NF-$\kappa$B is a key transcription factor. When activated by stress, it drives the production of pro-inflammatory cytokines like TNF-$\alpha$.
3. Epigenetic Modulation via lncRNAs: Perhaps most uniquely, the paper finds that APME modulates specific long non-coding RNAs. These are named FENDRR and Neat1. These molecules do not code for proteins. Instead, they act as scaffolds or regulators that influence how other genes are expressed. The authors report that APME downregulates these lncRNAs. These molecules are typically elevated during active inflammation and fibrosis (the thickening of connective tissue).

Evidence of dose-dependent recovery

To validate this mechanism, the researchers utilized an acetic acid-induced colitis model in rats. They measured several biochemical and histological (tissue-level) markers. The paper reports that the therapeutic effects of APME are strictly dose-dependent. The 200 mg/kg dose consistently outperformed the 100 mg/kg dose.

The biological impact is visible across multiple scales of measurement. At the tissue level, the authors observe significant damage from acetic acid. This includes mucosal damage and the loss of goblet cells (specialized cells that secrete protective mucus). Treatment with 200 mg/kg of APME leads to a "near-complete preservation of colonic architecture" .

The molecular data provides the underlying rationale for this structural recovery. The paper finds that APME significantly reduces the expression of the inflammatory marker TNF-$\alpha$ and the apoptotic (programmed cell death) marker p53 . Regarding oxidative stress, the authors report that APME treatment significantly lowers malondialdehyde (MDA) levels. MDA is a byproduct of lipid peroxidation that signals cellular damage. APME also restores the total antioxidant capacity (TAC) of the colonic tissue . Finally, the qRT-PCR analysis confirms the genetic orchestration. It shows a significant upregulation of Nrf2 and HO-1. It also shows a concurrent downregulation of the inflammatory lncRNAs FENDRR and Neat1 .

Assessing the scope of the findings

While the results are compelling, the study is constrained by its experimental design. First, the research was conducted entirely in a rat model. Because the human immune system and gut microbiome possess different complexities, the translation to human clinical efficacy remains unproven.

Second, although the authors successfully isolated two bioactive compounds—stigmasterol and 20-hydroxyecdysone—the study does not isolate the individual contributions of the other 33 identified metabolites. It is unclear if the benefits stem from these specific molecules or a synergistic effect of the entire extract. Finally, the paper focuses on the acute phase of colitis induction. It does not explore the long-term effects of chronic APME administration or its impact on the gut microbiota composition itself.

Verdict: A promising natural candidate

Is APME ready for the clinic? Not yet. Moving from a successful rodent model to a human therapeutic requires rigorous clinical trials. These trials must establish human dosing and safety profiles.

However, for researchers looking for new therapeutic targets, this study provides a specific roadmap. By identifying the modulation of FENDRR and Neat1 lncRNAs, the authors have surfaced two potentially viable molecular targets. These could be used for future IBD drug development. The study moves the conversation beyond simple cytokine suppression. It moves toward a holistic approach of restoring redox homeostasis and epigenetic stability.

Figures from the paper