Stercurensin inhibits nuclear factor-κB-dependent inflammatory signals through attenuation of TAK1-TAB1 complex formation

Discovery of anti-inflammatory natural flavonoids: Diverse scaffolds and promising leads for drug discovery

Natural products have been utilized for medicinal purposes for millennia, endowing them with a rich source of chemical scaffolds and pharmacological leads for drug discovery. Among the vast array of natural products, flavonoids represent a prominent class, renowned for their diverse biological activities and promising therapeutic advantages. Notably, their anti-inflammatory properties have positioned them as promising lead compounds for developing novel drugs combating various inflammatory diseases. This review presents a comprehensive overview of flavonoids, highlighting their manifold anti-inflammatory activities and elucidating the underlying pathways in mediating inflammation. Furthermore, this review encompasses systematical classification of flavonoids, related anti-inflammatory targets, involved in vitro and in vivo test models, and detailed statistical analysis. We hope this review will provide researchers engaged in active natural products and anti-inflammatory drug discovery with practical information and potential leads.

Inhibition of the Akt/NF-κB pathway is involved in the anti-gastritis effects of an ethanolic extract of the rhizome of Atractylodes macrocephala

ETHNOPHARMACOLOGICAL RELEVANCE

Gastritis can lead to ulcers and the development of gastric cancer. The rhizome of Atractylodes macrocephala Koidz. (Asteraceae), a traditional Chinese medicinal herb, is prescribed for the treatment of gastric disorders, hepatitis and rheumatism. Its bio-active compounds are considered to be particularly effective in this regard. However, the molecular processes of the herb's anti-inflammatory activity remain obscure. This study elucidates a mechanism upon which an ethanolic extract of this herb (Am-EE) exerts anti-inflammation effects in RAW264.7 macrophage cells (RAW cells) stimulated by lipopolysaccharide (LPS) treatment and HCl Ethanol-stimulated gastritis rats.

AIM OF THE STUDY

To investigate the anti-gastritis activities of Am-EE and explore the mode of action.

MATERIALS AND METHODS

Ethanol (95%) was used to prepare Am-EE. The quality of the extract was monitored by HPLC analysis. The in vivo effects of this extract were examined in an HCl Ethanol-stimulated gastritis rat model, while LPS-stimulated RAW cells were used for in vitro assays. Cell viability and nitric oxide (NO) production were observed by MTT and Griess assays. Real-time PCR was used to examine mRNA expression. The PGE₂ ELISA kit was employed to detect prostaglandin E₂ (PGE₂). Enzyme activities and protein contents were examined by immunoblotting. Luciferase reporter gene assays (LRA) were employed to observe nuclear transcription factor (NF)-κB activity. The SPSS (SPSS Inc., Chicago, Illinois, United States) application was used for statistical examination.

RESULTS

HPLC analysis indicates that Am-EE contains atractylenolide-1 (AT-1, 1.33%, w/w) and atractylenolide-2 (AT-2, 1.25%, w/w) (Additional Figure. A1). Gastric tissue damage (induced by HCl Ethanol) was significantly decreased in SD rats following intra-gastric application of 35 mg/kg Am-EE. Indistinguishable to the anti-inflammation effects of 35 mg/kg ranitidine (gastric medication). Am-EE treatment also reduced LPS-mediated nitric oxide (NO) and prostaglandin E₂ (PGE₂) production. The mRNA and protein synthesis of inducible cyclooxygenase (COX)-2 and NO synthase (iNOS) was down-regulated following treatment in RAW cells. Am-EE decreased NF-κB (p50) nuclear protein levels and inhibited NF-κB-stimulated LRA activity in RAW cells. Lastly, Am-EE decreased the up-regulated levels of phosphorylated IκBα and Akt proteins in rat stomach lysates and in LPS challenged RAW cell samples.

CONCLUSION

Our study illustrates that Am-EE suppresses the Akt/IκBα/NF-κB pathway and exerts an anti-inflammatory effect. These novel conclusions provide a pharmacological basis for the clinical use of the A. macrocephala rhizome in the treatment and prevention of gastritis and gastric cancer.

The anti-inflammatory effects of an ethanolic extract of the rhizome of Atractylodes lancea, involves Akt/NF-κB signaling pathway inhibition

ETHNOPHARMACOLOGICAL RELEVANCE

The dried rhizome of Atractylodes lancea (Thumb.) DC. (Compositae) has been prescribed in folk medicine for the management of various inflammatory conditions such as rheumatic diseases, gastritis and hepatitis. However, the molecular mechanisms underlying the beneficial properties of this herb remain elusive.

AIM OF THE STUDY

In this study, we investigated the anti-gastritis activities of Al-EE (an ethanolic extract of the herb) and explored the mechanism of action.

MATERIALS AND METHODS

An ethanolic extract of the Atractylodes lancea (Thumb.) DC. (Compositae) rhizome, Al-EE, was prepared with ethanol (95%) and quality controlled using HPLC analysis. To determine the in vivo effects of this extract, we utilised a HCl/EtOH-induced gastritis rat model. In vitro assays were carried out using a lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cell model. MTT assays were used to examine cell viability, while Griess assays were carried out to measure nitric oxide (NO) production. Messenger RNA expression was examined by real-time PCR. Prostaglandin E₂ (PGE₂) production was examined using ELISA assays. To examine protein expression and enzymatic activities, we employed western blot analysis. Nuclear transcription factor (NF)-κB activity was determined by Luciferase reporter assays.

RESULTS

The content of atractylenolide (AT)-1 and AT-2 in Al-EE was 0.45% and 5.07% (w/w), respectively (Supplementary Fig. 1). Al-EE treatment suppressed the production of NO and PGE₂, reduced the mRNA expression of inducible NO synthase (iNOS), cyclooxygenase (COX)-2 and tumor necrosis factor (TNF)-α, while also reducing the protein levels of iNOS and COX-2 in RAW264.7 macrophage cells. Furthermore, Al-EE inhibited the nuclear protein levels of NF-κB (p65) and NF-κB-driven luciferase reporter gene activity in RAW264.7 macrophage cells. Critically, intra-gastric injection of Al-EE (25 mg/kg) attenuated HCl/EtOH-induced gastric damage in SD rats, while the phosphorylation of Akt and IκBα was suppressed by Al-EE in vitro and in vivo.

CONCLUSION

In summary, Al-EE has significant anti-gastritis effects in vivo and in vitro, which can be associated with the inhibition of the Akt/IκBα/NF-κB signalling pathway. This mechanistic finding provides a pharmacological basis for the use of the A. lancea rhizome in the clinical treatment of various inflammatory conditions.

Fisetin alleviates sepsis-induced multiple organ dysfunction in mice via inhibiting p38 MAPK/MK2 signaling

Sepsis-induced multiple organ dysfunction and inflammatory response are life-threatening symptoms without effective treatment. Fisetin, a dietary flavonoid extracted from berries and family Fabaceae, has displayed neuroprotective and anti-oxidant activities. In this study we investigated whether fisetin exerted a protective effect against sepsis-induced multiple organ dysfunction in mouse cecum ligation and puncture (CLP) model. The mice were injected with fisetin (10 mg/kg, ip) 0.5 h prior to CLP, and sacrificed 18 h after CLP. We found that fisetin administration significantly alleviated CLP-induced lung, liver and kidney injury, as well as the expression levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α and IL-1β in bronchoalveolar lavage fluid (BALF). In lipopolysaccharide (LPS)-treated mouse bone marrow-derived macrophages (BMDMs), application of fisetin (3–10 μM) dose-dependently inhibited the expression levels of IL-6, TNF-α, IL-1β, and inducible nitric oxide synthase (iNOS). Furthermore, fisetin dose-dependently inhibited the phosphorylation of p38 MAPK, MK2, and transforming growth factor-β-activated kinase (TAK) 1 via attenuating the interaction between TAK1 and TAK-binding proteins (TAB) 1. These results demonstrate that fisetin is a promising agent for protecting against sepsis-induced inflammatory response and organ injury via inhibiting macrophage activation.

An ethanol extract of the rhizome of Atractylodes chinensis exerts anti-gastritis activities and inhibits Akt/NF-κB signaling

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizome of Atractylodes chinensis (DC.) kodiz (Compositae) has traditionally been used to treat inflammatory disorders such as arthritis and stomach ache, but scanted report has been issued on its anti-inflammatory mechanisms.

AIM OF THE STUDY

Here, we investigated the anti-gastritis activities and explored the mechanism of action of an ethanolic extract of the herb (Ac-EE).

MATERIALS AND METHODS

Ac-EE was prepared with 95% ethanol. To determine its in vivo effects, we employed an HCl/EtOH-induced gastritis rat model. We used a lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage model for in vitro assays. Griess and MTT assays were used to measure nitric oxide (NO) production and cell viability, respectively. We used real-time PCR to determine mRNA levels. To measure prostaglandin E₂ (PGE₂) production we used a PGE₂ EIA kit. To estimate protein levels and enzyme activities, we employed immunoblotting. Luciferase assays were used to examine nuclear transcription factor (NF)-κB activities.

RESULTS

Intragastric administration of Ac-EE (30 mg/kg) ameliorated HCl/EtOH-induced stomach tissue damages in SD rats. Ac-EE inhibited the levels of NO and PGE_2, down regulated mRNA and protein levels of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2. Ac-EE suppressed the nuclear level of NF-κB (p50), and inhibited NF-κB luciferase activity. The Phosphorylation of Akt and IκBα was also inhibited by Ac-EE both in vivo and in vitro.

CONCLUSION

Ac-EE treatment exerts an anti-gastritis effect in rats. Inhibition of the Akt/IκBα/NF-κB signaling pathway is associated with this effect, providing a pharmacological basis for the clinical application of the rhizome of A. chinensis in the treatment of inflammatory diseases.

Wnt11 Gene Therapy with Adeno-associated Virus 9 Improves Recovery from Myocardial Infarction by Modulating the Inflammatory Response

Acute myocardial infarction induces activation of the acute phase response and infiltration of leukocytes to the infarcted area. Moreover, myocardium that is remote from ischemic area also becomes inflamed. Inflammatory reaction clears dead cells and matrix debris, while prolongation or expansion of the inflammatory response results in dysfunction following myocardial infarction. Wnt glycolipoproteins are best characterized as regulators of embryonic development. Recently several reports suggest that they also contribute to the inflammatory response in adult animals. However, the effects of Wnt proteins on myocardial infarction have not been explored. Here we show that Wnt11 expression leads to significant improvements of survival and cardiac function by suppressing infiltration of multiple kinds of inflammatory cells in infarcted heart. Wnt11 protein suppresses gene expression of inflammatory cytokines through the modulation of NF-κB in vitro. These results reveal a novel function of Wnt11 in the regulation of inflammatory response and provide a rationale for the use of Wnt11 to manipulate human diseases that are mediated by inflammation.

Molecular targeted approaches to cancer therapy and prevention using chalcones

There is an emerging paradigm shift in oncology that seeks to emphasize molecularly targeted approaches for cancer prevention and therapy. Chalcones (1,3-diphenyl-2-propen-1-ones), naturally-occurring compounds with widespread distribution in spices, tea, beer, fruits and vegetables, consist of open-chain flavonoids in which the two aromatic rings are joined by a three-carbon α, β-unsaturated carbonyl system. Due to their structural diversity, relative ease of chemical manipulation and reaction of α, β-unsaturated carbonyl moiety with cysteine residues in proteins, some lead chalcones from both natural products and synthesis have been identified in a variety of screening assays for modulating important pathways or molecular targets in cancers. These pathways and targets that are affected by chalcones include MDM2/p53, tubulin, proteasome, NF-kappa B, TRIAL/death receptors and mitochondria mediated apoptotic pathways, cell cycle, STAT3, AP-1, NRF2, AR, ER, PPAR-γ and β-catenin/Wnt. Compared to current cancer targeted therapeutic drugs, chalcones have the advantages of being inexpensive, easily available and less toxic; the ease of synthesis of chalcones from substituted benzaldehydes and acetophenones also makes them an attractive drug scaffold. Therefore, this review is focused on molecular targets of chalcones and their potential implications in cancer prevention and therapy.

Striking a balance: autophagy, apoptosis, and necrosis in a normal and failing heart

Despite the progress that has been made over the past two decades in cardiovascular research, heart failure remains a major cause of morbidity and mortality worldwide. Insight into the cellular and molecular mechanisms that underlie the heart failure in individuals with ischemic heart disease have identified defects in cellular processes that govern autophagy, apoptosis and necrosis as a prevailing underlying cause. Indeed, programmed cell death of cardiac cells by apoptosis or necrosis is believed to involve the intrinsic mitochondrial pathway and/or extrinsic death receptor pathway by certain Bcl-2 family members as well as components of the TNFα signaling pathway. In this review, we discuss recent advances in the molecular signaling factors that govern cardiac cell fate under normal and disease conditions.

Taraxerol inhibits LPS-induced inflammatory responses through suppression of TAK1 and Akt activation

Taraxerol, a triterpenoid compound, has potent anti-inflammatory effects. However, the molecular mechanisms are not clear. In the study, taraxerol concentration dependently inhibited nitric-oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the protein and mRNA levels and these inhibitions decreased the production of nitric oxide (NO), prostaglandin 2 (PGE2), tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-1β induced by LPS. Furthermore, we found that taraxerol suppressed translocation of nuclear factor-κB (NF-κB), phosphorylation of IκBα, blocked the IκBα degradation as well as IKK and mitogen-activated protein kinase (MAPK) activation by inactivation of TGF-β-activated kinase-1 (TAK1) and Akt. In addition, taraxerol significantly inhibited the formation of TAK1/TAK-binding protein1 (TAB1), which was accompanied by inducing degradation of TAK1, decreasing LPS-induced polyubiquitination of TAK1 as well as TAK1 phosphorylation. Taken together, our data suggest that taraxerol downregulates the expression of proinflammatory mediators in macrophages by interfering with the activation of TAK1 and Akt, thus preventing NF-κB activation.

Red ginseng marc oil inhibits iNOS and COX-2 via NFκB and p38 pathways in LPS-stimulated RAW 264.7 macrophages

In this study, we investigated the anti-inflammatory effects of red ginseng marc oil (RMO) in the RAW 264.7 macrophage cell line. RMO was prepared by a supercritical CO₂ extraction of waste product generated after hot water extraction of red ginseng. RMO significantly inhibited the production of oxidative stress molecules such as nitric oxide and reactive oxygen species in lipopolysaccharide (LPS)-activated RAW 264.7 cells. Levels of inflammatory targets including prostaglandin E2, tumor necrosis factor-α, interleukin (IL)-1β and IL-6 were also reduced after the treatment with RMO. In addition, RMO diminished the expressions of inducible nitric oxide synthase and cyclooxygenase 2 at both mRNA and protein levels. Blockade of nuclear translocation of the p65 subunit of nuclear factor κB (NFκB) was also observed after the treatment of RMO. Furthermore, RMO decreased the phosphorylations of p38 mitogen-activated protein kinase (MAPK) and its upstream kinases including MAPK kinases 3/6 (MKK3/6) and TAK 1 (TGF-β activated kinase 1). Gas chromatographic analysis on RMO revealed that RMO contained about 10% phytosterols including sitosterol, stigmasterol and campesterol which may contribute to the anti-inflammatory properties of RMO. Taken together, these results suggest that the anti-inflammatory effect of RMO in LPS-induced RAW 264.7 macrophages could be associated with the inhibition of NFκB transcriptional activity, possibly via blocking the p38 MAPK pathway.