Barbaloin Attenuates Mucosal Damage in Experimental Models of Rat Colitis by Regulating Inflammation and the AMPK Signaling Pathway

Barbaloin Protects Pentylenetetrazol-Induced Cognitive Deficits in Rodents via Modulation of Neurotransmitters and Inhibition of Oxidative-Free-Radicals-Led Inflammation

BACKGROUND

Epilepsy is defined by an excessive level of activity in the neurons and coordinated bursts of electrical activity, resulting in the occurrence of seizure episodes. The precise cause of epileptogenesis remains uncertain; nevertheless, the etiology of epilepsy may involve neuroinflammation, oxidative stress, and malfunction of the neurotransmitter system.

OBJECTIVE

The goal of this investigation was to assess barbaloin's protective properties with respect to pentylenetetrazol (PTZ)-)-induced cognitive deficits in rats via antioxidative, anti-inflammatory, and neurotransmitter-modulating effects.

METHODS

Wistar rats were subjected to PTZ [40 mg/kg (i.p.)], which induced cognitive decline. Behavior assessment using a kindling score, open-field test (OFT), novel object recognition test (NORT), and assays for superoxide dismutase (SOD), reduced glutathione (GSH), catalase (CAT), malondialdehyde (MDA), acetylcholinesterase (AChE), caspase-3, nitric oxide (NO), interleukins-1β (IL-1β), tumor necrosis factor-α (TNF-α), IL-6, nuclear factor kappa-B (NF-κB), Bcl-2 and Bax, and neurotransmitter levels [GABA, DA, NE, and serotonin (5-HT)] were performed.

RESULTS

The treatment of rats with barbaloin resulted in behavior improvement and significant changes in the levels of GSH, SOD, CAT, MDA, AChE, NO, IL-6, IL-1β, TNF-α, NF-κB, caspase-3, Bcl-2, and Bax compared to the PTZ control group. Barbaloin treatment resulted in notable changes in neurotransmitter levels (GABA, NE, 5-HT, DA) compared to the PTZ group.

CONCLUSIONS

The ongoing study has gathered evidence indicating that the injection of barbaloin has resulted in significant improvements in cognitive performance in rats. This is achieved by inhibiting oxidative stress, enhancing the activity of natural antioxidant enzymes, reducing cytokine levels, and increasing the levels of neurotransmitters in the brain. These results were detected in comparison to a PTZ control and can be attributed to the potent anti-inflammatory and antioxidant capabilities of barbaloin, which could be linked to its neuroprotective properties. Barbaloin may potentially increase cognitive decline and boost neuronal survival by altering the expression of Bax, caspase-3, Bcl-2.

Barbaloin's Chemical Intervention in Aluminum Chloride Induced Cognitive Deficits and Changes in Rats through Modulation of Oxidative Stress, Cytokines, and BDNF Expression

Alzheimer's disease (AD) is a long-term neurodegenerative condition characterized by impaired cognitive functions, particularly in the domains of learning and memory. Finding promising options for AD can be successful with a medication repurposing strategy. The goal of the research was to examine the neuroprotective characteristics of barbaloin in aluminum chloride (AlCl3)-induced cognitive deficits and changes in rats through modulation of oxidative stress, cytokines, and brain-derived neurotrophic factor (BDNF) expression. Thirty male Wistar rats were subjected to AlCl3 at a dosage of 100 mg/kg via the per oral route (p.o.), which induced cognitive decline. Morris water maze (MWM) is used to assess behavioral metrics. Assays for catalase (CAT), malondialdehyde (MDA), reduced glutathione (GSH), acetylcholinesterase (AChE), choline-acetyltransferase (ChAT), interleukins-1β (IL-1β), superoxide dismutase (SOD), tumor necrosis factor-α (TNF-α), nuclear factor kappa-B (NF-κB), interleukins-6 (IL-6), BDNF, and neurotransmitter levels [dopamine (DA), acetylcholine (Ach), and γ-aminobutyric acid (GABA)] were performed. Results: The transfer latency time was notably decreased, and substantial modifications in the concentrations of GSH, MDA, CAT, SOD, AChE, ChAT and observed modulations in the formation of interleukins-6 (IL-6), TNF-α, IL-1β, BDNF, and NF-κB were also evidenced after the treatment of rats with barbaloin in comparison to AlCl3-induced control groups. Significant alterations in neurotransmitter levels (DA, Ach, and GABA) were also seen in barbaloin-treated groups in comparison to AlCl3-induced groups. The current investigation has provided evidence that the administration of barbaloin yielded notable enhancements in cognitive function in rats through the inhibition of MDA, enhancing endogenous antioxidant enzymes, reduction of cytokine levels, and enhancement of neurotransmitter contents in the brain. These effects were observed in comparison to a control group treated with AlCl3 and can be attributable to barbaloin's strong anti-inflammatory and antioxidant properties, and metal chelating properties may contribute to its neuroprotective effects. Barbaloin may also promote neuronal survival and enhance learning and memory by upregulating the expression of BDNF.

Multiple Beneficial Effects of Aloesone from Aloe vera on LPS-Induced RAW264.7 Cells, Including the Inhibition of Oxidative Stress, Inflammation, M1 Polarization, and Apoptosis

Aloesone is a major metabolic compound in Aloe vera, which has been widely used as a food source and therapeutic agent in several countries. Our recent study demonstrated that aloesone has anti-epileptic effects on glutamate-induced neuronal injury by suppressing the production of reactive oxygen species (ROS). Unless ROS are naturally neutralized by the endogenous antioxidant system, they lead to the activation of inflammation, polarization, and apoptosis. This study aimed to identify the multiple beneficial effects of aloesone and explore its molecular mechanism in macrophages. Hence, the murine macrophage cell line RAW264.7 was pretreated with aloesone and then exposed to lipopolysaccharides (LPS). The results demonstrated that aloesone, within a dosage range of 0.1-100 µM, dramatically decreased the LPS-induced elevation of ROS production, reduced nitric oxide (NO) release, inhibited the M1 polarization of RAW264.7 cells, and prevented cells from entering the LPS-induced early and late phases of apoptosis in a dose-dependent manner. Simultaneously, aloesone significantly decreased the mRNA expression of inflammation-related genes (iNOS, IL-1ꞵ, TNF-α) and increased the expression of antioxidant enzymes (Gpx-1 and SOD-1). The core genes HSP90AA1, Stat3, Mapk1, mTOR, Fyn, Ptk2b, and Lck were closely related to these beneficial effects of aloesone. Furthermore, immunofluorescence staining and flow cytometry data confirmed that aloesone significantly repressed the activation of mTOR, p-mTOR, and HIF-1α induced by LPS and inhibited the protein expression of TLR4, which is the target of LPS. In conclusion, aloesone demonstrated multiple protective effects against LPS-induced oxidative stress, inflammation, M1 polarization, and apoptosis in macrophages, suggesting its potential as a prodrug.

Aloin A prevents ulcerative colitis in mice by enhancing the intestinal barrier function via suppressing the Notch signaling pathway

BACKGROUND

Previous studies reported that Aloe vera ameliorated DSS-induced colitis and promoted mucus secretion. However, the effect of Aloin A (AA), a major compound of Aloe vera, on colitis and its exact mechanism remains uncovered.

METHODS

C57BL/6 mice were successively subjected to 3% DSS solution for 5 days and distilled water for 2 days. Concurrently, AA (25, 50 mg/kg) and 5-aminosalicylic (500 mg/kg) were administrated intragastrically from day 1 to day 7. Colitis was evaluated by disease active index (DAI), colon length, inflammation response, and intestinal barrier function. In vitro LS174T cells challenged with 50 ng/ml of lipopolysaccharides (LPS) were used to validate the modulatory action of AA on the Notch signaling pathway.

RESULTS

Our results showed that oral administration with AA prominently prevented DSS-induced colitis symptoms in terms of decreased DAI, prevention of colon shortening, and reduced pathological damage. AA mitigated the inflammatory response evidenced by the decreased proinflammatory cytokines (TNF-α, IL-1β, IL-6) and increased anti-inflammatory cytokine (IL-10). Besides, AA inhibited apoptosis and facilitated proliferation in colons. Moreover, AA treatment up-regulated the expression of tight junction (TJ) proteins (ZO-1, Occludin) and promoted the secretion of MUC2 to decrease colon permeability. Mechanistically, AA inhibited the Notch pathway to promote the secretion of MUC2, which was consistent with LPS-challenged LS174 cells.

CONCLUSION

These results suggested that AA could prevent colitis by enhancing the intestinal barrier function via suppressing the Notch signaling pathway. Thus, AA might be a prospective remedy for ulcerative colitis.

Sestrin2 suppresses ferroptosis to alleviate septic intestinal inflammation and barrier dysfunction

OBJECTIVE

Alterations in intestinal function play a crucial role in the pathogenesis of sepsis, and the repair of the intestinal barrier is a potential strategy for the treatment of sepsis. Sestrin2 (SESN2), a highly conserved stress-responsive protein, can be induced in response to stress.

AIM

This paper aimed to explore the role and mechanism of SESN2 in septic intestinal dysfunction. Methods: Blood samples were collected from patients with septic intestinal dysfunction, and Caco-2 cells were subjected to lipopolysaccharide (LPS) to construct in vitro models. The expression level of SESN2 was determined in the blood samples and cells. The impacts of SESN2 overexpression on cell inflammation, oxidative stress, barrier integrity, and MAPK/Nrf2 signaling were evaluated. To determine the mediated role of MAPK signaling and ferroptosis, AMPK inhibitor (Compound C) and ferroptosis inducer (erastin) were separately used to treat cells, and the influences on the above aspects in cells were assessed.

RESULTS

The expression level of SESN2 was down-regulated in patients with septic intestinal dysfunction and LPS-induced cells. SESN2 overexpression was found to suppress cell inflammation and oxidative stress, maintain barrier integrity and activate AMPK/Nrf2 signaling. Following the AMPK signaling was inhibited or the ferroptosis was triggered, the effects of SESN2 overexpression on the cells were both reversed.

CONCLUSION

Reduced SESN2 contributed to inflammatory response and barrier dysfunction in septic intestinal dysfunction by promoting ferroptosis via activating the AMPK/Nrf2 signaling pathway.

The potential health benefits of aloin from genus Aloe

The Aloe species is known for its medicinal and cosmetic properties. Aloin is an active ingredient found in the leaves of medicinal plants of the genus Aloe. Aloin has attracted considerable interest for its antiinflammatory, anticancer, antibacterial, and antioxidant activities. However, since its clinical application is restricted by its unclear mechanism of action, a deeper understanding of its pharmacological activity is required. This review provides an overview of current pharmacological and toxicological studies published in English from February 2000 to August 2021. Herein, we summarized the sources and potential health benefits of aloin from a clinical application perspective to guide for further studies on the sources of aloin, aimed at efficiently increasing aloin production. Importantly, the function and mechanism of action of aloin remain unclarified. In future research, it is necessary to develop new approaches for studying the pharmacological molecular mechanisms underlying the activity of this compound against various diseases.

Therapeutic Promises of Medicinal Plants in Bangladesh and Their Bioactive Compounds against Ulcers and Inflammatory Diseases

When functioning properly, the stomach is the center of both physical and mental satisfaction. Gastrointestinal disorders, or malfunctioning of the stomach, due to infections caused by various biological entities and physiochemical abnormalities, are now widespread, with most of the diseases being inflammatory, which, depending on the position and degree of inflammation, have different names such as peptic or gastric ulcers, irritable bowel diseases, ulcerative colitis, and so on. While many synthetic drugs, such as non-steroidal anti-inflammatory drugs, are now extensively used to treat these diseases, their harmful and long-term side effects cannot be ignored. To treat these diseases safely and successfully, different potent medicinal plants and their active components are considered game-changers. In consideration of this, the present review aimed to reveal a general and comprehensive updated overview of the anti-ulcer and anti-inflammatory activities of medicinal plants. To emphasize the efficacy of the medicinal plants, various bioactive compounds from the plant extract, their experimental animal models, and clinical trials are depicted.

Deletion of intestinal epithelial AMP-activated protein kinase alters distal colon permeability but not glucose homeostasis

Objective

The intestinal epithelial barrier (IEB) restricts the passage of microbes and potentially harmful substances from the lumen through the paracellular space, and rupture of its integrity is associated with a variety of gastrointestinal disorders and extra-digestive diseases. Increased IEB permeability has been linked to disruption of metabolic homeostasis leading to obesity and type 2 diabetes. Interestingly, recent studies have uncovered compelling evidence that the AMP-activated protein kinase (AMPK) signaling pathway plays an important role in maintaining epithelial cell barrier function. However, our understanding of the function of intestinal AMPK in regulating IEB and glucose homeostasis remains sparse.

Methods

We generated mice lacking the two α1 and α2 AMPK catalytic subunits specifically in intestinal epithelial cells (IEC AMPK KO) and determined the physiological consequences of intestinal-specific deletion of AMPK in response to high-fat diet (HFD)-induced obesity. We combined histological, functional, and integrative analyses to ascertain the effects of gut AMPK loss on intestinal permeability in vivo and ex vivo and on the development of obesity and metabolic dysfunction. We also determined the impact of intestinal AMPK deletion in an inducible mouse model (i-IEC AMPK KO) by measuring IEB function, glucose homeostasis, and the composition of gut microbiota via fecal 16S rRNA sequencing.

Results

While there were no differences in in vivo intestinal permeability in WT and IEC AMPK KO mice, ex vivo transcellular and paracellular permeability measured in Ussing chambers was significantly increased in the distal colon of IEC AMPK KO mice. This was associated with a reduction in pSer425 GIV phosphorylation, a marker of leaky gut barrier. However, the expression of tight junction proteins in intestinal epithelial cells and pro-inflammatory cytokines in the lamina propria were not different between genotypes. Although the HFD-fed AMPK KO mice displayed suppression of the stress polarity signaling pathway and a concomitant increase in colon permeability, loss of intestinal AMPK did not exacerbate body weight gain or adiposity. Deletion of AMPK was also not sufficient to alter glucose homeostasis or the acute glucose-lowering action of metformin in control diet (CD)- or HFD-fed mice. CD-fed i-IEC AMPK KO mice also presented higher permeability in the distal colon under homeostatic conditions but, surprisingly, this was not detected upon HFD feeding. Alteration in epithelial barrier function in the i-IEC AMPK KO mice was associated with a shift in the gut microbiota composition with higher levels of Clostridiales and Desulfovibrionales.

Conclusions

Altogether, our results revealed a significant role of intestinal AMPK in maintaining IEB integrity in the distal colon but not in regulating glucose homeostasis. Our data also highlight the complex interaction between gut microbiota and host AMPK.

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Deletion of intestinal AMPKα1 and α2 suppresses the stress-polarity signaling (SPS) pathway.

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Loss of the SPS pathway is associated with increased paracellular permeability in the distal colon.

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Intestinal AMPK is dispensable for the acute glucose-lowering action of metformin.

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Loss of intestinal AMPK alters the gut microbiota composition.

Barbaloin Treatment Contributes to the Rebalance of Glucose and Lipid Homeostasis of Gestational Diabetes Mellitus Mice

Aloe vera L has been shown to possess hypoglycemic and hypolipidemic effects on type 2 diabetic patients, and its major benefits may be linked to barbaloin, which is a major component of Aloe vera L. This study focused on investigating the potential effects and underlying mechanisms of barbaloin on gestational diabetes mellitus (GDM). The db/+ diabetic mice with GDM were daily orally administered with barbaloin or metformin during the gestational period. The results demonstrated that administration of barbaloin significantly reduced blood glucose levels and increased insulin levels in GDM mice. We further found that barbaloin treatment reduced inflammatory response and ROS levels in the liver. Finally, we revealed that the AMP-activated protein kinase (AMPK) / peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) signaling pathway was involved in BAT-mediated beneficial effects on mice with GDM. Our study suggested that barbaloin exerted hypoglycemic and hypolipidemic effects on GDM mice, via, at least in part, modulation of AMPK/ PGC-1α signaling in GDM mice.

Inhibition of PI3K/Akt/NF-κB signaling by Aloin for ameliorating the progression of osteoarthritis: In vitro and in vivo studies

Osteoarthritis (OA) is a progressive and degenerative joint disease. Aloin is a bitter and yellow-brown-coloured compound from the Aloe plant and is allowed for use in foods as a "natural flavour". In our study, we examined the protective effects of Aloin on the inhibition of OA development as well as its underlying mechanism in both in vitro and vivo experiments. In in-vitro experiments, the protective effect of aloin on the anabolism and catabolism of the extracellular matrix (ECM) induced by IL-1 β in chondrocytes by inhibiting the expression of pro-inflammatory factors, including TNF-α (p = 0.016), IL-6 (p = 0.006), iNOS (p = 0.001) and COX-2 (p = 0.006). Mechanistically, Aloin suppressed the IL-1β-induced activation of the PI3K/Akt/NF-κB signalling pathway cascades. Moreover, molecular docking studies demonstrated that Aloin bound strongly to PI3K. In vivo, Aloin ameliorated the OA process in the destabilization of the medial meniscus (DMM) model. In summary, our findings demonstrate that Aloin ameliorates the progression of OA via the PI3K/Akt/NF-κB signalling pathways, which supports Aloin as a promising therapeutic agent for the treatment of OA.