Chicoric Acid Ameliorates Lipopolysaccharide-Induced Oxidative Stress via Promoting the Keap1/Nrf2 Transcriptional Signaling Pathway in BV-2 Microglial Cells and Mouse Brain

Research progress on the role and inhibitors of Keap1 signaling pathway in inflammation

Inflammation is a protective mechanism against endogenous and exogenous pathogens. It is a typical feature of numerous chronic diseases and their complications. Keap1 is an essential target in oxidative stress and inflammatory diseases. Among them, the Keap1-Nrf2-ARE pathway (including Keap1-Nrf2-HO-1) is the most significant pathway of Keap1 targets, which participates in the control of inflammation in multiple organs (including renal inflammation, lung inflammation, liver inflammation, neuroinflammation, etc.). Identifying new Keap1 inhibitors is crucial for new drug discovery. However, most drugs have specificity issues as they covalently bind to cysteine residues of Keap1, causing off-target effects. Therefore, direct inhibition of Keap1-Nrf2 PPIs is a new research idea. Through non-electrophilic and non-covalent binding, its inhibitors have better specificity and ability to activate Nrf2, and targeting therapy against Keap1-Nrf2 PPIs has become a new method for drug development in chronic diseases. This review summarizes the members and downstream genes of the Keap1-related pathway and their roles in inflammatory disease models. In addition, we summarize all the research progress of anti-inflammatory drugs targeting Keap1 from 2010 to 2024, mainly describing their biological functions, molecular mechanisms of action, and therapeutic roles in inflammatory diseases.

Ultra-Performance Liquid Chromatography and Mass Spectrometry Characterization, and Antioxidant, Protective, and Anti-Inflammatory Activity, of the Polyphenolic Fraction from Ocimum basilicum

Ocimum basilicum is a valuable plant widely consumed worldwide and considered a rich source of polyphenols. This study examined the impact of the polyphenolic fraction isolated from basil (ObF) on human normal colon epithelial cells and human colorectal adenocarcinoma cells, evaluating its anti-inflammatory and protective activity against oxidative stress. The phytochemical characterization of the fraction was performed using ultra-performance liquid chromatography (UPLC) with a photodiode detector (DAD) and mass spectrometry (MS). UPLC-DAD-MS revealed that ObF predominantly contains caffeic acid derivatives, with rosmarinic acid and chicoric acid being the most abundant. The fraction demonstrated high antioxidant potential, as shown by DPPH assays, along with significant reducing power (FRAP). Furthermore, it prevented the depletion of antioxidant enzymes, including superoxide dismutase and catalase, and decreased malonylodialdehyde (MDA) in induced oxidative stress condition. Additionally, it exhibited a significant protective effect against H2O2-induced cytotoxicity in human normal colon epithelial cells. Although it had no impact on the viability of adenocarcinoma cells, it significantly reduced IL-1β levels in the neoplastic microenvironment. Our study demonstrated that basil polyphenols provide significant health benefits due to their antioxidant and protective activities.

Chicory supplementation improves growth performance in juvenile ostriches potentially by attenuating enteritis

Introduction

Enteritis and dysbiosis are the major causes of high morbidity and mortality of juvenile ostriches. Chicory (CC) has been proven to have excellent antioxidant, anti-inflammatory, and antibacterial activities. However, it's unclear whether CC could improve the survival rate of juvenile ostriches by relieving enteritis and correcting dysbiosis.

Materials and methods

South African ostrich hatchlings (Struthio camelus domesticus) were fed with and without a CC-supplemented diet, and the body weight gain and mortality were compared over 4 months of age. Fresh fecal samples of clinically healthy ostriches were collected, and 16S DNAs were analyzed. Moreover, ostrich chicks with LPS-induced enteritis were fed with different dosages (0, 20, 40, and 80 mg/kg) of chicoric acid (CA), a major bioactive component of CC, for five consecutive days. The expression levels of tight junction (TJ)-related proteins and inflammatory mediators in the ilea were detected with western blot and immunofluorescence.

Results

The ostrich chicks fed on the CC-supplemented diet began to increase in weight at the 1st month of age and became remarkably heavier at the fourth month (p < 0.01) compared with those fed on the non-CC-supplemented diet. Additionally, the mortality percentage was lower in the chicks fed on the CC-supplemented diet than those fed on the non-CC-supplemented diet (19% vs. 36%, respectively). The diet with the CC supplementation significantly increased the abundance of Phascolactobacteria (linear discriminant analysis; LDA >4) and Bacteroidota (26.7% vs. 17.7%, respectively) as well as decreased the enrichment of Clostridium (5.0% vs. 9.1%, respectively) in the ostrich ilea compared to the diet without CC. The supplementation of CA at a dose of 80 mg/kg significantly increased the expression level of ZO-1 and claudin-3 (p < 0.0001) and suppressed the levels of IL-1β, IL-6, and TNF-α (p < 0.0001) in ostriches with LPS-induced ileitis.

Conclusion

Our results substantiate that CC or CA supplementation in a diet could effectively improve growth performance and reduce mortality in juvenile ostriches via modulating the gut microbiota and attenuating enteritis.

Stevioside Ameliorates Prenatal Obesity Induced Postpartum Depression: The Potential Role of Gut Barrier Homeostasis

SCOPE

Postpartum depression and cognitive impairment are the common complications of prenatal obesity. Stevioside is a non-nutritive natural sweetener with antioxidant and anti-inflammatory. However, its effects on depression behaviors and cognitive impairment induced by a high-fat diet (HFD) remain unclear.

METHODS AND RESULTS

An 8-week HFD is used to establish a prenatal obesity model in female C57BL/6J mice to explore the improvement effects of stevioside (0.5 mg mL-1 in drinking water) on maternal depression and cognitive dysfunction after weaning. The results demonstrated that stevioside improves behavioral performance of obese maternal mice, and inhibits neuronal damage and 5-hydroxytryptamine (5-HT) abnormality induced by HFD. In addition, stevioside inhibits oxidative stress by reducing malondialdehyde (MDA) and increasing superoxide dismutase (SOD) and glutathione (GSH) activities in the brains of obese maternal mice. Additionally, stevioside improves gut barrier integrity and prevented lipopolysaccharide (LPS) extravasation, and alleviates neuroinflammation. Correlation analysis shows that gut barrier and serum LPS are closely related to behavioral performance and brain biochemical indicators.

CONCLUSION

Stevioside is capable to prevent prenatal obesity-induced cognitive and mood disorders by restoring intestinal barrier damage and inhibiting inflammation.

Armillariella tabescens-derived polysaccharides alleviated Ɒ-Gal-induced neuroinflammation and cognitive injury through enterocerebral axis and activation of keap-1/Nrf2 pathway

The early symptoms of neurodegenerative diseases include oxidative stress disorder and accelerated inflammation levels. Edible fungi polysaccharides play essential roles in anti-neuroinflammation. We analyzed the regulatory mechanisms of polysaccharides from extracellular Armillariella tabescens (ATEP) in alleviating neuroinflammation in mice. Mice were induced with d-galactose and aluminum chloride to establish an animal model of Alzheimer's disease, then intragastrically treated with ATEP, which had been previously analyzed for its physicochemical properties. We assessed the critical characteristics of mice treated for neuroinflammation, including cognitive behavior, the anti-inflammatory potential of ATEP in hippocampal pathology and critical protein expression, and changes in fecal microbial composition and metabolites. ATEP intervened in oxidative stress by enhancing antioxidant enzyme activities and suppressing the Keap-1/Nrf2 signaling pathway. Changing the Nrf2 content in the nucleus led to changes in the downstream oxidation-related enzymes, HO-1, NQO-1, iNOS, and COX-2, and the neuronal morphology in CA3 region of the hippocampus. Microbiome analysis revealed that ATEP remodeled the gut microbiotas and regulated the short-chain fatty acids-producing bacteria. Early intervention with ATEP via active dietary supplementation may promote neuroprotection.

Chicoric Acid Alleviates Colitis via Targeting the Gut Microbiota Accompanied by Maintaining Intestinal Barrier Integrity and Inhibiting Inflammatory Responses

Polyphenols have shown great potential to prevent ulcerative colitis. As a natural plant polyphenol, chicoric acid (CA) has antioxidant and anti-inflammatory properties. This study explored the intervention effects and potential mechanism of CA on dextran sodium sulfate (DSS)-induced colitis mice. The results showed that CA alleviated the symptoms of colitis and maintained the intestinal barrier integrity. CA significantly downregulated the mRNA expression levels of inflammatory factors including IL-6, IL-1β, TNF-α, IFN-γ, COX-2, and iNOS. In addition, CA modulated the gut microbiota by improving the microbial diversity, reducing the abundance of Gammaproteobacteriaand Clostridium_XI and increasing the abundance ofBarnesiellaandLachnospiraceae. Further fecal microbiota transplantation experiments showed that FM from CA donor mice significantly alleviated the symptoms of colitis, verifying the key role of gut microbiota. These results indicate that CA effectively relieves DSS-induced colitis via targeting gut microbiota along with preserving intestinal barrier function and suppressing inflammatory responses.

Polyphenolic Characterization and Anti-Inflammatory Effect of In Vitro Digested Extracts of Echinacea purpurea L. Plant Parts in an Inflammatory Model of Human Colon Cells

Echinacea purpurea L. (EP) preparations are globally popular herbal supplements known for their medicinal benefits, including anti-inflammatory activities, partly related to their phenolic composition. However, regarding their use for the management of inflammation-related intestinal diseases, the knowledge about the fate of orally ingested constituents throughout the human gastrointestinal tract and the exposition of in vitro digested extracts in relevant inflammatory models are unknown. This study investigated for the first time the impact of in vitro gastrointestinal digestion (INFOGEST) on the phenolic composition and anti-inflammatory properties of EP extracts from flowers (EF), leaves (EL), and roots (ER) on IL-1β-treated human colon-derived CCD-18Co cells. Among the seven hydroxycinnamic acids identified using HPLC-UV-MS/MS, chicoric and caftaric acids showed the highest concentrations in EL, followed by EF and ER, and all extracts exerted significant reductions in IL-6, IL-8, and PGE2 levels. After digestion, despite reducing the bioaccessibility of their phenolics, the anti-inflammatory effects were preserved for digested EL and, to a lesser extent, for EF, but not for digested ER. The lower phenolic content in digested EF and ER could explain these findings. Overall, this study emphasizes the potential of EP in alleviating intestinal inflammatory conditions and related disorders.

Shank3 ameliorates neuronal injury after cerebral ischemia/reperfusion via inhibiting oxidative stress and inflammation

Shank3, a key molecule related to the development and deterioration of autism, has recently been found to downregulate in the murine brain after ischemia/reperfusion (I/R). Despite this discovery, however, its effects on neuronal injury and the mechanism underlying the effects remain to be clarified. To address this, in this study, based on genetically modified mice models, we revealed that the expression of Shank3 showed a time-dependent change in murine hippocampal neurons after I/R, and that conditional knockout (cko) of Shank3 in neurons resulted in aggravated neuronal injuries. The protective effects of Shank3 against oxidative stress and inflammation after I/R were achieved through direct binding STIM1 and subsequent proteasome-mediated degradation of STIM1. The STIM1 downregulation induced the phosphorylation of downstream Nrf2 Ser40, which subsequently translocated to the nucleus, and further increased the expression of antioxidant genes such as NQO1 and HO-1 in HT22 cells. In vivo, the study has further confirmed that double knockout of Shank3 and Stim1 alleviated oxidative stress and inflammation after I/R in Shank3cko mice. In conclusion, the present study has demonstrated that Shank3 interacts with STIM1 and inhibits post-I/R neuronal oxidative stress and inflammatory response via the Nrf2 pathway. This interaction can potentially contribute to the development of a promising method for I/R treatment.

An Insight into the Promising Therapeutic Potential of Chicoric Acid

The pharmacological treatments that are now recommended for the therapy of chronic illnesses are examined in a great number of studies to determine whether or not they are both safe and effective. Therefore, it is important to investigate various alternative therapeutic assistance, such as natural remedies derived from medicinal plants. In this context, chicoric acid, classified as a hydroxycinnamic acid, has been documented to exhibit a range of health advantages. These include antiviral, antioxidant, anti-inflammatory, obesity-preventing, and neuroprotective effects. Due to its considerable pharmacological properties, chicoric acid has found extensive applications in food, pharmaceuticals, animal husbandry, and various other commercial sectors. This article provides a comprehensive overview of in vitro and in vivo investigations on chicoric acid, highlighting its beneficial effects and therapeutic activity when used as a preventative and management aid for public health conditions, including diabetes, cardiovascular disease, and hepatic illnesses like non-alcoholic steatohepatitis. Moreover, further investigation of this compound can lead to its development as a potential phytopharmaceutical candidate.

Chicoric acid ameliorates LPS-induced inflammatory injury in bovine lamellar keratinocytes by modulating the TLR4/MAPK/NF-κB signaling pathway

Damage to lamellar keratinocytes, an essential cellular component of the epidermal layer of hoof tissue, can have a detrimental effect on hoof health and the overall production value of dairy cows. We isolated and cultured cow lamellar keratinocytes using the Dispase II and collagenase methods. We purified them by differential digestion and differential velocity adherent methods at each passaging and identified them by keratin 14 immunofluorescence. We established an in vitro model of inflammation in laminar keratinocytes using LPS and investigated whether chicoric acid protects against inflammatory responses by inhibiting the activation of the TLR4/MAPK/NF-κB signaling pathway. The results showed that cow lamellar keratinocytes were successfully isolated and cultured by Dispase II combined with the collagenase method. In the in vitro inflammation model established by LPS, the Chicoric acid decreased the concentration of inflammatory mediators (TNF-α, IL-1β, and IL-6), down-regulated the mRNA expression of TLR4 and MyD88 (P < 0.01), down-regulated the expression of TLR4, MyD88, p-ERK, p-p38, IKKβ, p-p65, p-p50 (P < 0.05), and increased the IκBα protein expression (P < 0.05). In conclusion, Chicoric acid successfully protected cow lamellar keratinocytes from LPS-induced inflammatory responses by modulating the TLR4/MAPK/NF-κB signaling pathway and downregulating inflammatory mediators.

An emerging role of arecoline on growth performance, intestinal digestion and absorption capacities and intestinal structural integrity of adult grass carp (Ctenopharyngodon idella)

Arecoline is an alkaloid with important pharmacological effects in the plant areca nut, which has been demonstrated to be an agonist of muscarinic receptors (M receptor). This study explored the influences of dietary arecoline on growth performance, intestinal digestion and absorption abilities, antioxidant capacity, and the apical junction complex (AJC) of adult grass carp (Ctenopharyngodon idella). Adult grass carp (608 to 1512 g) were fed at 6 graded levels of dietary arecoline (0, 0.5, 1.0, 1.5, 2.0, and 2.5 mg/kg diet) for 9 weeks. The results suggested that appropriate dietary supplementation of arecoline (1.0 mg/kg) increased growth parameters and intestinal growth in adult grass carp (P < 0.05), enhanced digestion and absorption capacities (P < 0.05), up-regulated muscarinic receptor 3 (M3) mRNA level (P < 0.05), increased the content of neuropeptide fish substance P (P < 0.05), improved antioxidant capacity by activating the Keap1a/Nrf2 signaling pathway (P < 0.05), reduced intestinal mucosal permeability (P < 0.05), and increased mRNA levels of tight junction (TJ) and adherent junction AJ-related proteins in fish by inhibiting the RhoA/ROCK signaling pathway (RhoA/ROCK/MLCK/NMII) (P < 0.05). In addition, the appropriate arecoline supplementation for adult grass carp was determined to be 1.20, 1.21, 1.07, and 1.19 mg/kg based on percentage weight gain, lipase activity, serum diamine oxidase, and protein carbonyl, respectively. Overall, to the best of our knowledge, we investigated for the first time the effects and possible mechanisms of dietary arecoline on intestinal digestive and absorptive capacities and structural integrity in fish and evaluated the appropriate level of supplementation.

Chicoric acid enhances the antioxidative defense system and protects against inflammation and apoptosis associated with the colitis model induced by dextran sulfate sodium in rats

Although several anticolitic drugs are available, their application is associated with numerous side effects. Chicoric acid (CA) is a hydroxycinnamic acid found naturally in chicory (Cichorium intybus), purple coneflower (Echinacea purpurea), and basil with numerous health benefits, such as antioxidative and anti-inflammatory activities. Here, the potential anticolitic efficiency of CA against dextran sulfate sodium (DSS)-induced colitis in rats was examined in rats. Animals were randomly assigned to the following five groups: control, CA (100 mg/kg body weight), DSS [(DSS); 4% w/v], CA + DSS (100 mg/kg), and the 5-aminosalicylic acid (100 mg/kg) + DSS group. The obtained data revealed that CA significantly prevented the shortening of colon length. Meanwhile, the oxidative stress-related enzymes were increased, while malondialdehyde and nitric oxide, were markedly decreased significantly by CA. The results also indicated that CA administration decreased significantly the pro-apoptogenic indices (Bax and caspase-3) and enhanced significantly Bcl-2, the anti-apoptogenic protein. Moreover, DSS caused a significant elevation of pro-inflammatory mediators, including interleukin-1β, tumor necrosis factor-α, myeloperoxidase, cyclooxygenase II, prostaglandin E2, and peroxisome proliferator-activated receptor gamma. Interestingly, these changes were significantly decreased following the CA administration. At the molecular level, CA supplementation has increased significantly the expression level of nuclear factor erythroid 2-related factor-2 (Nrf2) and decreased the expressions of nitric oxide synthase and mitogen-activated protein kinase 14. CA has been determined to significantly lessen DSS-induced colitis by activating Nrf2 and its derived antioxidant molecules and suppressing inflammation and apoptosis cascades associated with the development of colitis; suggesting that CA could be used as an alternative naturally-derived anticolitic agent.

An integrated phytochemical, in silico and in vivo approach to identify the protective effect of Caroxylon salicornicum against cisplatin hepatotoxicity

Cisplatin (CIS) is a chemotherapeutic medication for the treatment of cancer. However, hepatotoxicity is among the adverse effects limiting its use. Caroxylon salicornicum is traditionally used for treating inflammatory diseases. In this investigation, three flavonoids, four coumarins, and three sterols were detected in the petroleum ether fraction of C. salicornicum (PEFCS). The isolated phytochemicals exhibited binding affinity toward Keap1, NF-κB, and SIRT1 in silico. The hepatoprotective role of PEFCS (100, 200 and 400 mg/kg) was investigated in vivo. Rats received PEFCS for 14 days and CIS on day 15. CIS increased ALT, AST and ALP and caused tissue injury along with increased ROS, MDA, and NO. Hepatic NF-κB p65, pro-inflammatory mediators, Bax and caspase-3 were increased in CIS-treated animals while antioxidants and Bcl-2 were decreased. PEFCS mitigated hepatocyte injury, and ameliorated transaminases, ALP, oxidative stress (OS) and inflammatory markers. PEFCS downregulated pro-apoptosis markers and boosted Bcl-2 and antioxidants. In addition, PEFCS upregulated Nrf2, HO-1, and SIRT1 in CIS-administered rats. In conclusion, PEFCS is rich in beneficial phytoconstituents and conferred protection against liver injury by attenuating OS and inflammation and upregulating Nrf2 and SIRT1.

Health Benefits of Key Constituents in Cichorium intybus L

The genus Cichorium (Asteraceae) that originates from the Mediterranean area consists of six species (Cichorium intybus, Cichorium frisee, Cichorium endivia, Cichorium grouse, Cichorium chico and Cichorium pumilum). Cichorium intybus L., commonly known as chicory, has a rich history of being known as a medicinal plant and coffee substitute. A variety of key constituents in chicory play important roles as antioxidant agents. The herb is also used as a forage plant for animals. This review highlights the bioactive composition of C. intybus L. and summarizes the antioxidant activity associated with the presence of inulin, caffeic acid derivatives, ferrulic acid, caftaric acid, chicoric acid, chlorogenic and isochlorogenic acids, dicaffeoyl tartaric acid, sugars, proteins, hydroxycoumarins, flavonoids and sesquiterpene lactones. It also covers the plant's occurrence, agriculture improvement, natural biosynthesis, geographical distribution and waste valorization.

Role of Plant-Derived Compounds in the Molecular Pathways Related to Inflammation

Inflammation is the primary response to infection and injury. Its beneficial effect is an immediate resolution of the pathophysiological event. However, sustained production of inflammatory mediators such as reactive oxygen species and cytokines may cause alterations in DNA integrity and lead to malignant cell transformation and cancer. More attention has recently been paid to pyroptosis, which is an inflammatory necrosis that activates inflammasomes and the secretion of cytokines. Taking into consideration that phenolic compounds are widely available in diet and medicinal plants, their role in the prevention and support of the treatment of chronic diseases is apparent. Recently, much attention has been paid to explaining the significance of isolated compounds in the molecular pathways related to inflammation. Therefore, this review aimed to screen reports concerning the molecular mode of action assigned to phenolic compounds. The most representative compounds from the classes of flavonoids, tannins, phenolic acids, and phenolic glycosides were selected for this review. Our attention was focused mainly on nuclear factor-κB (NF-κB), nuclear factor erythroid 2-related factor 2 (Nrf2), and mitogen-activated protein kinase (MAPK) signaling pathways. Literature searching was performed using Scopus, PubMed, and Medline databases. In conclusion, based on the available literature, phenolic compounds regulate NF-κB, Nrf2, and MAPK signaling, which supports their potential role in chronic inflammatory disorders, including osteoarthritis, neurodegenerative diseases, cardiovascular, and pulmonary disorders.

Characterization of tangeretin as an activator of nuclear factor erythroid 2-related factor 2/antioxidant response element pathway in HEK293T cells

Numerous studies have reported that tangeretin is a polymethoxylated flavone with a variety of biological activates, but little research has been done on the antioxidant mechanism of tangeretin. Hence, we investigated the effect of tangeretin on the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway and its potential molecular mechanisms by in vitro and in silico research. The results of molecular docking suggested that tangeretin bound at the top of the central pore of Kelch-like ECH-associated protein 1 (Keap1) Kelch domain, and the hydrophobic and hydrogen bond interactions contributed to their stable binding. Herein, the regulation of Nrf2-ARE pathway by tangeretin was explored in the human embryonic kidney cell line HEK293T, which is relatively easy to be transfected. Upon binding to tangeretin, Nrf2 translocated to the nucleus of HEK293T cells, which in turn activated the Nrf2-ARE pathway. Luciferase reporter gene analysis showed that tangeretin significantly induced ARE-mediated transcriptional activation. Real-time PCR and Western blot assays showed that tangeretin induced the gene and protein expressions of Nrf2-mediated targets, including heme oxygenase 1 (HO-1), nicotinamide adenine dinucleotide phosphate (NADPH) quinone dehydrogenase 1 (NQO1), and glutamate-cysteine ligase (GCLM). In addition, tangeretin could effectively scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals. In summary, tangeretin may be a potential antioxidant via activating the Nrf2-ARE pathway.

Re-Visiting Antioxidant Therapy in Murine Advanced Atherosclerosis with Brussels Chicory, a Typical Vegetable in Mediterranean Diets

Brussels chicory, a typical vegetable in Mediterranean diets, has been recently reported to stabilize advanced atherosclerotic plaques in the brachiocephalic artery of apoE-deficient (Apoe-/-) mice. Herein, we investigated whether Brussels chicory can stabilize advanced plaques in the aorta via improving oxidative stress. Thirty week old Apoe-/- mice were fed the AIN-93G diet or supplemented with 0.5% freeze-dried Brussels chicory for twenty weeks. Aortic plaque size and stability, aortic relaxation, monocyte adhesion to aortic endothelium, free radicals, and enzymatic and non-enzymatic factors involved in free radical production and elimination in aorta and serum were measured. Brussels chicory consumption did not alter aortic plaque size, however, it stabilized aortic plaques, promoted aortic relaxation, and also inhibited monocyte adhesion to aortic endothelium. Moreover, this administration reduced oxidized LDL (ox-LDL) and 4-hydroxynonenal (4-HNE) content in aortic plaques, associated with inhibited aortic NADPH oxidase (NOX) and uncoupled endothelial nitric oxide synthase (eNOS)-mediated free radical production. However, Brussels chicory consumption did not appreciably alter aortic and serum superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities, aortic glutathione (GSH), as well as serum non-enzymatic antioxidants, such as bilirubin, uric acid, and GSH. Collectively, improved oxidative stress might contribute to the atheroprotective effect of Brussels chicory, supporting the prospect of the antioxidant therapy in advanced atherosclerosis progression.

Echinacea purpurea against neuropathic pain: Alkamides versus polyphenols efficacy

Chemotherapy-induced neuropathy represents the main dose-limiting toxicity of several anticancer drugs, such as oxaliplatin, leading to chronic pain and an impairment of the quality of life. Echinacea purpurea n-hexane extract (EP₄ -R_E ; rich in alkamides) and butanolic extract (EP₄ -R_BU ; rich in polyphenols) have been characterized and tested in an in vivo model of oxaliplatin-induced neuropathic pain, addressing the endocannabinoid system with alkamides and counteracting the redox imbalance with polyphenols. Thermal hypersensitivity was evaluated by the Cold Plate test. EP₄ -R_E showed a dose-dependent anti-hyperalgesic profile. The extract was more effective than its main constituent, dodeca-2 E,4 E,8Z,10 E/Z-tetraenoic acid isobutylamide (18 mg kg^-1 , twofold to equimolar EP₄ -R_E 30 mg kg^-1 ), suggesting a synergy with other extract constituents. Administration of cannabinoid type 2 (CB2) receptor-selective antagonist completely blocked the anti-allodynic effect of EP₄ -R_E , differently from the antagonism of CB1 receptors. EP₄ -R_BU (30 mg kg^-1 ) exhibited anti-neuropathic properties too. The effect was mainly exerted by chicoric acid, which administered alone (123 μg kg^-1 , equimolar to EP₄ -R_BU 30 mg kg^-1 ) completely reverted oxaliplatin-induced allodynia. A synergy between different polyphenols in the extract had not been highlighted. Echinacea extracts have therapeutic potential in the treatment of neuropathic pain, through both alkamides CB2-selective activity and polyphenols protective properties.

Protective effects of chicoric acid on LPS-induced endometritis in mice via inhibiting ferroptosis by Nrf2/HO-1 signal axis

Chicoric acid (CA), a natural phenolic acid extracted from Mediterranean vegetable chicory, has anti-oxidative effect. We aimed to investigate the effects of CA on endometritis and clarify the underlying mechanism. C57BL/6 mice were divided into five groups: control group, LPS group, and LPS + CA groups. All mice except control group were infused of LPS into the uterus. The mice of LPS + CA groups were intraperitoneally injected CA 1 h before LPS challenge. CA significantly alleviatedLPS-induced pathological damage, MPO activity, and inflammatory cytokine production. CA significantly suppressed ferroptosis in LPS-induced endometritis. CA also attenuated LPS-induced NF-κB activation. Furthermore, Nrf2 and HO-1 expression were increased by CA. Moreover, the inhibition of CA on LPS-induced endometritis and ferroptosis were markedly prevented in Nrf2 knockdown mice. In conclusion, the results suggested CA protected mice against LPS-induced endometritisthrough inhibiting ferroptosis via Nrf2/HO-1 signaling pathway.

Chicoric acid attenuates tumor necrosis factor-α-induced inflammation and apoptosis via the Nrf2/HO-1, PI3K/AKT and NF-κB signaling pathways in C28/I2 cells and ameliorates the progression of osteoarthritis in a rat model

Osteoarthritis (OA) is the most common arthritis, and is characterized by inflammation and cartilage degradation. Chicoric acid (CA), a bioactive caffeic acid derivative isolated from the root of Taraxacum mongolicumHand. - Mazz., has been reported to have anti-inflammatory effects. However, the therapeutic effects of CA on chondrocyte inflammation remain unknown. Our study aimed to explore the effect of CA on OA both in vivo and in vitro. In vitro, CA treatment significantly suppressed the overproduction of nitric oxide (NO), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and IL-12 in tumor necrosis factor alpha (TNF-α)-induced human C28/I2 chondrocytes. Moreover, CA attenuated TNF-α induced degradation of the extracellular matrix (ECM) by upregulating the expression of collagen Ⅱ and aggrecan, and downregulating ADAMTS-5 and matrix metalloproteinases (MMPs). Additionally, CA treatment inhibited apoptosis in C28/I2 cells by upregulating of Bcl-2 levels, downregulating Bax and ROS levels, and activating the Nrf2/HO-1 pathway. Mechanistically, CA exerted an anti-inflammatory effect by inhibiting the PI3K/AKT and NF-κB signaling pathways, enhancing Nrf-2/HO-1 to limit the activation of NF-κB. In vivo experiments also proved the therapeutic effects of CA on OA in rats. These findings indicate that CA may become a new drug for the treatment of OA.

Lycopene attenuates D-galactose-induced insulin signaling impairment by enhancing mitochondrial function and suppressing the oxidative stress/inflammatory response in mouse kidneys and livers

Lycopene (LYC) possesses bioactivity to improve the pathogenesis of several chronic diseases via antioxidant-associated mechanisms. The purpose of this study was to investigate whether LYC could attenuate D-galactose (D-gal)-induced mitochondrial dysfunction and insulin signaling impairment in mouse kidneys and livers. Two-month-old CD-1 mice were treated by intraperitoneal injection of 150 mg kg^-1 day^-1D-gal for 8 weeks and received 0.03% LYC (w/w, mixed into diet). The results showed that LYC ameliorated oxidative stress triggered by D-gal by enhancing the Nrf2 antioxidant defense pathway and increasing the expression of the antioxidant response genes HO-1 and NQO1 in mouse kidneys and livers. LYC inhibited the MAPK and NFκB pathways and attenuated renal and hepatic inflammatory responses. Moreover, LYC upregulated the expression of genes related to mitochondrial biosynthesis and oxidative phosphorylation and improved insulin signal transduction through the IRS-1/AKT/GSK3β pathway in mouse kidneys and livers.

Chicoric Acid: Natural Occurrence, Chemical Synthesis, Biosynthesis, and Their Bioactive Effects

Chicoric acid has been widely used in food, medicine, animal husbandry, and other commercial products because of its significant pharmacological activities. However, the shortage of chicoric acid limits its further development and utilization. Currently, Echinacea purpurea (L.) Moench serves as the primary natural resource of chicoric acid, while other sources of it are poorly known. Extracting chicoric acid from plants is the most common approach. Meanwhile, chicoric acid levels vary in different plants as well as in the same plant from different areas and different medicinal parts, and different extraction methods. We comprehensively reviewed the information regarding the sources of chicoric acid from plant extracts, its chemical synthesis, biosynthesis, and bioactive effects.

Cichoric Acid May Play a Role in Protecting Hair Cells from Ototoxic Drugs

Ototoxic hearing loss due to antibiotic medication including aminoglycosides and excess free radical production causes irreversible hair cell injury. Cichoric acid, a naturally occurring phenolic acid, has recently been found to exert anti-oxidative and anti-inflammatory properties through its free radical scavenging capacity. The present study aimed to investigate the protective effects of cichoric acid against neomycin-induced ototoxicity using transgenic zebrafish (pvalb3b: TagGFP). Our results indicated that cichoric acid in concentrations up to 5 μM did not affect zebrafish viability during the 2 h treatment period. Therefore, the otoprotective concentration of cichoric acid was identified as 5 μM under 2 h treatment by counting viable hair cells within the neuromasts of the anterior- and posterior-lateral lines in the study. Pretreatment of transgenic zebrafish with 5 μM of cichoric acid for 2 h significantly protected against neomycin-induced hair cell death. Protection mediated by cichoric acid was, however, lost over time. A terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and FM4-64 staining, respectively, provided in situ evidence that cichoric acid ameliorated apoptotic signals and mechanotransduction machinery impairment caused by neomycin. A fish locomotor test (distance move, velocity, and rotation frequency) assessing behavioral alteration after ototoxic damage revealed rescue due to cichoric acid pretreatment before neomycin exposure. These findings suggest that cichoric acid in 5 μM under 2 h treatment has antioxidant effects and can attenuate neomycin-induced hair cell death in neuromasts. Although cichoric acid offered otoprotection, there is only a small difference between pharmacological and toxic concentrations, and hence cichoric acid can be considered a rather prototypical compound for the development of safer otoprotective compounds.

Cyanidin-3-O-glucoside, cyanidin, and oxidation products of cyanidin protect neuronal function through alleviating inflammation and oxidative damage

Neurotoxicity seriously affects the normal function of the nervous system. Cyanidin-3-O-glucoside (C3G) is the most abundant anthocyanin widely distributed in plants. Using β-amyloid (Aβ) transgenic Caenorhabditis elegans and cell models, the neuroprotective effect of C3G was examined. The results showed that C3G remarkably suppressed Aβ aggregation, enhanced antioxidant capacity, improved the sensitive capacity towards chemical compounds, and boosted the memory ability of C. elegans. There was no significant difference between preventive and long-term treatment groups at the same dosage of C3G. Given the rapid metabolism and oxidation of C3G in vivo, the antioxidative and anti-inflammatory activities of C3G, the metabolite cyanidin (Cy), oxidation products of Cy (OP), as well as protocatechuic acid (PCA) at the corresponding level in OP were compared by using lipopolysaccharide (LPS)-stimulated BV2 microglia cell model. The results indicated that C3G, Cy, and OP could prevent BV2 cells against LPS-induced inflammation and oxidative damage. There was no significant difference on antioxidative and anti-inflammatory activities among C3G, Cy, and OP at the same level. Notably, PCA at the corresponding concentration in OP exhibited limited antioxidative and anti-inflammatory activities. The results suggested that C3G could exert neuroprotective function through the metabolite Cy and its oxidation products by inhibiting inflammation and oxidative damage, and PCA was not the primary bioactive species in OP. PRACTICAL APPLICATION: This study confirmed the neuroprotection of cyanidin-3-O-glucoside (C3G) in transgenic Caenorhabditis elegans. C3G, its metabolite cyanidin (Cy), and oxidation products of Cy (OP) alleviated both neuroinflammation and oxidative damage. It highlighted that C3G-rich foods could exert neuroprotective potential through their oxidation products, the constitution, and existence of OP in vivo need further study.

Dietary chitooligosaccharide supplementation alleviates intestinal barrier damage, and oxidative and immunological stress in lipopolysaccharide-challenged laying hens

This study aimed to investigate the effects of chitooligosaccharide (COS) on intestinal barrier, antioxidant capacity, and immunity of lipopolysaccharide (LPS)-challenged laying hens. A total of 360 Hy-line Brown laying hens (80-wk-old) were randomly divided into 5 groups with 6 replicates of 12 birds. Hens were fed a corn-soybean meal basal diet supplemented with different COS levels (0; 5; 10; 15; 20 mg/kg) for 8 wk. The results showed that 15 mg/kg COS administration elevated albumen height and Haugh unit (P < 0.05), and numerically optimized productive performance (P > 0.05), therefore, the dosage of 15 mg/kg was chosen for the subsequent experiment. Thereafter, 12 birds from non-supplemented group were randomly selected and assigned into 2 groups, and birds in each group were administered (1.5 mg/kg BW, i.p.) with saline (control group) or LPS (challenge group). Another 6 hens from 15 mg/kg COS-supplemented group were selected and injected with LPS in the same way. Compared with the control group, LPS-challenged birds exhibited elevated circulating diamine oxidase activity, and reduced jejunal villus height and ratio of villus height to crypt depth, and these indices were reversed to control levels by COS (P < 0.05). Also, LPS increased malondialdehyde accumulation and reduced several antioxidant enzyme activities in the intestinal mucosa (P < 0.05). Additionally, LPS increased jejunal secretory IgA and interferon-γ (IFN-γ), and ileal secretory IgA, IgM, and interleukin-1β (IL-1β) concentrations, whereas COS reduced jejunal IFN-γ and IL-1β, and ileal IgM levels (P < 0.05). Moreover, LPS down-regulated mRNA abundance of jejunal occludin and claudin 2, and upregulated expression of jejunal nuclear factor erythroid-2 related factor 2, superoxide dismutase 1, and IFN-γ as well as ileal IL-1β (P < 0.05). Besides, COS increased jejunal occludin and ileal claudin 2, nuclear factor erythroid-2 related factor 2, and heme oxygenase-1 expression, and decreased jejunal IFN-γ and IL-1β abundance (P < 0.05). These results suggested that COS could alleviate LPS-induced intestinal barrier impairment, and oxidative and immunological stress in laying hens.

A comprehensive mechanistic and therapeutic insight into the effect of chicory (Cichorium intybus) supplementation in diabetes mellitus: A systematic review of literature

BACKGROUND

Cichorium intybus is a rich source of terpenoids and phenolic compounds, one of the effective methods in managing and reducing the complications of chronic diseases such as diabetes mellitus. The purpose of this systematic review was to evaluate the evidence obtained from animal and human studies on the effects of chicory on metabolic indicators (such as inflammation, oxidative stress, blood sugar and dyslipidaemia) of diabetes mellitus.

MATERIALS AND METHODS

This systematic search was performed in ProQuest, PubMed, Google Scholar, Scopus, Cochrane Central Register of Controlled Trials, Embase and Science Direct databases and on articles published until August 2021. All of the animal studies and clinical trials included in this systematic review that assessed the effect of chicory on metabolic risk markers in diabetes were published in English language journals.

RESULTS

Finally, amongst 686 articles, only 23 articles met the needed criteria for further analysis. Out of 23 articles, 3 studies on humans and 20 studies on animals have been carried out. Fifteen of the 19 studies that evaluated the effect of chicory on the glycaemic index showed that Cichorium intybus improved blood glucose index (it had no effect in two human studies and three animal studies). Ten of the 13 studies evaluating the effect of Cichorium intybus on lipid profiles showed that it improved dyslipidaemia. Also, all 12 studies showed that chicory significantly reduces oxidative stress and inflammation.

CONCLUSION

According to the available evidence, Cichorium intybus might improve the glycaemic status, dyslipidaemia, oxidative stress and inflammation. However, further studies are recommended for a comprehensive conclusion about the exact mechanism of chicory in diabetic patients.

Galangin Attenuates Liver Injury, Oxidative Stress and Inflammation, and Upregulates Nrf2/HO-1 Signaling in Streptozotocin-Induced Diabetic Rats

Chronic hyperglycemia increases the risk of liver damage. Oxidative stress and aberrant inflammatory response are entangled in diabetes-associated liver injury. This study evaluated the protective effect of the flavonoid galangin (Gal) on glucose intolerance, liver injury, oxidative stress, inflammatory response, and Nrf2/HO-1 signaling in diabetic rats. Diabetes was induced by streptozotocin (STZ), and the rats received Gal for six weeks. STZ-induced rats showed glucose intolerance, hypoinsulinemia, elevated glycated hemoglobin (HbA1c), and decreased liver glycogen. Gal ameliorated glucose intolerance, reduced HbA1c%, increased serum insulin and liver glycogen and hexokinase activity, and suppressed glycogen phosphorylase, glucose-6-phosphatase and fructose-1,6-biphosphatase in diabetic rats. Circulating transaminases, ALP and LDH, and liver ROS, MDA, TNF-α, IL-1β, and IL-6 were increased and GSH, SOD, and CAT were diminished in diabetic rats. In addition, diabetic rats exhibited multiple histopathological alterations and marked collagen deposition. Treatment with Gal mitigated liver injury, prevented histopathological alterations, decreased ROS, MDA, pro-inflammatory cytokines, Bax and caspase-3, and enhanced cellular antioxidants and Bcl-2. Gal downregulated hepatic Keap1 in diabetic rats and upregulated Nrf2 and HO-1 mRNA as well as HO-1 activity. Molecular modeling studies revealed the ability of Gal to bind to and inhibit NF-κB and Keap1, and also showed its binding pattern with HO-1. In conclusion, Gal ameliorates hyperglycemia, glucose intolerance, oxidative stress, inflammation, and apoptosis in diabetic rats. Gal improved carbohydrate metabolizing enzymes and upregulated Nrf2/HO-1 signaling.

Evaluation of Anti-inflammatory Nutraceuticals in LPS-induced Mouse Neuroinflammation Model: An Update

It is known that peripheral infections, accompanied by inflammation, represent significant risk factors for the development of neurological disorders by modifying brain development or affecting normal brain aging. The acute effects of systemic inflammation on progressive and persistent brain damage and cognitive impairment are well documented. Anti-inflammatory therapies may have beneficial effects on the brain, and the protective properties of a wide range of synthetic and natural compounds have been extensively explored in recent years. In our previous review, we provided an extensive analysis of one of the most important and widely-used animal models of peripherally induced neuroinflammation and neurodegeneration - lipopolysaccharide (LPS)-treated mice. We addressed the data reproducibility in published research and summarized basic features and data on the therapeutic potential of various natural products, nutraceuticals, with known anti-inflammatory effects, for reducing neuroinflammation in this model. Here, recent data on the suitability of the LPS-induced murine neuroinflammation model for preclinical assessment of a large number of nutraceuticals belonging to different groups of natural products such as flavonoids, terpenes, non-flavonoid polyphenols, glycosides, heterocyclic compounds, organic acids, organosulfur compounds and xanthophylls, are summarized. Also, the proposed mechanisms of action of these molecules are discussed.

Botanical formulation, TADIOS, alleviates lipopolysaccharide (LPS)-Induced acute lung injury in mice via modulation of the Nrf2-HO-1 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

TADIOS is an herbal formulation prepared from a mixture of Taraxacum officinale (L.) Weber ex F.H.Wigg, Dioscorea batatas Decaisne and Schizonepeta tenuifolia (Benth.) Briquet. These plants have traditionally been used in Asia to treat a variety of respiratory diseases. A bulk of literature on traditional Korean medicine describe their activities and functions for respiratory problems. Therefore, we hypothesized that the combination of these plants might be effective in alleviating respiratory symptoms.

AIM OF THE STUDY

In this study, we investigated whether TADIOS ameliorates LPS-induced acute lung injury via regulation of the Nrf2-HO-1 signaling pathway.

MATERIALS AND METHODS

The LPS-induced acute lung injury mouse model was used to determine the anti-inflammatory and anti-oxidative stress effects of TADIOS. The amount of marker compounds contained in TADIOS was quantified using high-performance liquid chromatography (HPLC) analysis. The protein level of pro-inflammatory cytokines in culture supernatant was measured by ELISA. Changes in the RNA level of pro-inflammatory cytokines in mice lungs and RAW264.7 cells were measured by quantitative RT-PCR. The relative amounts of reactive oxygen species (ROS) were measured by DCF-DA assay. Western blot analysis was used to evaluate expression of cellular proteins. Effects of TADIOS on antioxidant responsive elements (AREs) were determined by luciferase assay. The severity of acute lung injury was evaluated by Hematoxylin & Eosin (H&E) staining. To test the effects of TADIOS on LPS-induced oxidative stress, myeloperoxidase (MPO) activity and the total antioxidant capacity were measured.

RESULTS

TADIOS was prepared by extraction of a blend of these three plants by ethanol, and quality control was performed through quantification of marker compounds by HPLC and measurement of bioactivities using cell-based bioassays. In the murine macrophage cell line RAW264.7, TADIOS effectively suppressed the production of pro-inflammatory cytokines such as IL-6 and IL-1β, and also ROS induced by LPS. When RAW264.7 cells were transfected with a luciferase reporter plasmid containing nucleotide sequences for AREs, TADIOS treatment increased the level of relative luciferase units in a dose-dependent manner. In the LPS-induced acute lung injury mouse model, orally administered TADIOS alleviated lung damage and neutrophil infiltration induced by LPS. Consistent with the in vitro data, treatment with TADIOS inhibited the LPS-mediated expression of pro-inflammatory cytokines and oxidative stress, and activated the Nrf2-HO-1 axis.

CONCLUSION

Our data suggest the potential for TADIOS to be developed as a safe and effective therapeutics for the treatment of acute respiratory distress syndrome.

Effects of Bile Acids on Growth Performance and Lipid Metabolism during Chronic Heat Stress in Broiler Chickens

Simple Summary

The negative impacts of heat stress (HS) on growth performance and lipid metabolism have been reported, but there are still no effective nutritional strategies to alleviate heat stress. Bile acids are new for their antioxidative properties and regulatory effect on lipid metabolism. This study was carried out to evaluate the growth performance and lipid metabolism in chickens under heat stress when fed with bile acid supplements in their diet. The results showed that mild heat stress (32 °C) induced hepatic lipogenic gene (hepatic SREBP-1c) expressions and lipid deposition, without obvious tissue damage in broilers. Dietary supplementation of bile acid could decrease hepatic lipid deposition without affecting endogenous bile acid biosynthesis. Therefore, bile acid supplements can benefit broiler chickens during high ambient temperatures, serving as a new nutritional strategy against heat stress.

Abstract

This study aimed to investigate whether dietary bile acid (BA) supplements can improve growth performance and lipid metabolism in heat-stressed broiler chickens. A total of 288 Arbor Acres broilers were blocked by BW and then randomly allocated into 4 treatments at 21 days of age. Birds reared under 32 °C had a higher cloacal temperature (p = 0.01), faster respiratory rate (p < 0.001), and a greatly reduced average daily feed intake (ADFI, p = 0.016), average daily gain (ADG, p = 0.006), final body weight (FBW, p = 0.008), and feed conversion rate (FCR, p = 0.004). In heat stress (HS) birds, the breast muscle rate (p = 0.006) and pH 24 h postmortem (p = 0.065) were lower, and the shear force was higher (p = 0.027). Dietary BA supplements tended to increase the breast muscle rate (p = 0.075) without affecting the growth performance and serum lipids (p > 0.05). Serum total bile acid (TBA) was roughly duplicated after BA supplements (p = 0.001). In the liver, total cholesterol was lower (p = 0.046), and triglycerides were higher (p = 0.04) in the HS birds, whereas the expression of SREBP-1c showed an increasing trend (p = 0.06). In contrast, dietary BA decreased triglycerides and the expressions of hepatic SREBP-1c and FAS in the liver (p < 0.05). In summary, mild HS causes hepatic lipid accumulation without obvious tissue damages, whereas BA has positive effects on relieving abnormal lipid metabolism, indicating that BA as a nutritional strategy has a certain potential in alleviating HS.

Biochanin A alleviates gingival inflammation and alveolar bone loss in rats with experimental periodontitis

Biochanin A (BA) is an organic compound produced by Trifolium pretense and Arachis hypogaea with anti-inflammatory and antioxidative effects. The aim of the current study was to evaluate the effects of BA on gingival inflammation and alveolar bone destruction in rats with experimental periodontitis. Experimental rats (n=25) were distributed equally into five groups: i) Healthy control (control) group; ii) experimental periodontitis (ligation) group; and iii) and ligation plus low, medium and high dose of BA (12.5, 25 and 50 mg/kg/day, respectively) groups. A nylon ligature was inserted around rats' maxillary molars for 14 days to trigger the experimental periodontitis. BA was intravenous injected once daily for 4 weeks. After that, interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), reactive oxygen species (ROS) and osteocalcin (OCN) levels were determined in gingival and/or serum samples using ELISA or reverse transcription-quantitative PCR. Alveolar bone volume was assessed via hematoxylin and eosin staining and micro-computed tomography. Osteoclasts were identified by tartrate-resistant acid phosphatase staining, and the level of the nuclear factor erythroid-2 related factor 2 (Nrf2) was also detected by immunohistochemical staining. BA treatment groups showed alleviated alveolar bone resorption compared with the ligation group. Moreover, BA treatment significantly inhibited IL-1β, TNF-α, ROS levels, and reduced leukocyte acid phosphatase-positive cells, as well as increased OCN and Nrf2 levels compared with the ligation group. BA had beneficial effects on experimental periodontitis of rats. BA treatment inhibited inflammation, regulated unbalanced oxidative stress response and ameliorated the alveolar bone loss.

Neuroprotective Effects of Methyl Caffeate against Hydrogen Peroxide-Induced Cell Damage: Involvement of Caspase 3 and Cathepsin D Inhibition

Finding effective neuroprotective strategies to combat various neurodegenerative disorders still remain a clinically unmet need. Methyl caffeate (MC), a naturally occurring ester of caffeic acid, possesses antioxidant and anti-inflammatory activities; however, its role in neuroprotection is less investigated. In order to better characterize neuroprotective properties of MC, we tested its effectiveness in various models of neuronal cell injury in human neuroblastoma SH-SY5Y cells and in mouse primary neuronal cell cultures. MC at micromolar concentrations attenuated neuronal cell damage induced by hydrogen peroxide (H2O2) in undifferentiated and neuronal differentiated SH-SY5Y cells as well as in primary cortical neurons. This effect was associated with inhibition of both caspase-3 and cathepsin D but without involvement of the PI3-K/Akt pathway. MC was neuroprotective when given before and during but not after the induction of cell damage by H2O2. Moreover, MC was protective against 6-OHDA-evoked neurotoxicity in neuronal differentiated SH-SY5Y cells via inhibition of necrotic and apoptotic processes. On the other hand, MC was ineffective in models of excitotoxicity (induced by glutamate or oxygen-glucose deprivation) and even moderately augmented cytotoxic effects of the classical apoptotic inducer, staurosporine. Finally, in undifferentiated neuroblastoma cells MC at higher concentrations (above 50 microM) induced cell death and when combined with the chemotherapeutic agent, doxorubicin, it increased the cell damaging effects of the latter compound. Thus, neuroprotective properties of MC appear to be limited to certain models of neurotoxicity and depend on its concentrations and time of administration.

Chicoric acid improves neuron survival against inflammation by promoting mitochondrial function and energy metabolism

Chicoric acid (CA), a major nutraceutical component of a typical Mediterranean vegetable, chicory, possesses excellent antioxidant and anti-inflammatory bioactivities. This work aimed to elucidate the effects of CA on neuron survival against inflammation and the underlying molecular mechanisms. Results demonstrated that CA promoted SH-SY5Y cells' autophagic vesicle formation, up-regulated autophagic elongation phase related gene expressions, and inhibited apoptosis stimulated by microglial conditioned culture medium (MCM). In addition, CA significantly improved mitochondrial function and regulated redox homeostasis related signaling pathways such as MAPKs and PI3K/AKT. MCM with CA notably increased the expressions of PGC-1α, SIRT1 and enhanced the phosphorylation of AMPK, promoting energy metabolism. On the other hand, the underlying mechanisms of the intervention of CA in MCM-induced cell apoptosis were partly due to its direct protective effect on SH-SY5Y cells and inhibition of microglial inflammatory factor release. This establishes a theoretical foundation for neuro-nutrition intervention studies of natural functional food components, and provides new clues for developing health foods containing CA.

Isoflavone biochanin A, a novel nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element activator, protects against oxidative damage in HepG2 cells

Isoflavones are one group of the major flavonoids and possess multiple biological activities due to their antioxidant properties. However, a clear antioxidant mechanism of dietary isoflavones is still remained to be answered. In this study, the effects of isoflavones on the nuclear factor E2-related factor 2 (Nrf2)-antioxidant response element (ARE) signaling pathway and the underlying molecular mechanisms were investigated. Results showed that isoflavones are potential Nrf2-ARE activators while their activities were structure dependent. Biochanin A (BCA), an O-methylated isoflavone with low direct antioxidant activity, can effectively protect HepG2 cells against tert-butyl hydroperoxide (t-BHP)-induced oxidative damage via activation of the Nrf2 signaling, and thereby the induction of downstream cytoprotective enzymes including NAD(P)H quinone oxidoreductase-1, heme oxygenasae-1, and glutamate-cysteine ligase catalytic subunit. A molecular docking study revealed that BCA could directly bind into the pocket of Kelch-like erythroid cell-derived protein with CNC homology (ECH)-associated protein 1 (Keap1), a cytoplasmic suppressor of Nrf2, to facilitate Nrf2 activation. The upstream mitogen-activated protein kinase (MAPK) pathways were also involved in the activation of Nrf2 signaling. These findings indicate that the protective actions of dietary isoflavones against oxidative damage may be at least partly due to their ability to enhance the intracellular antioxidant response system by modulating the Nrf2-ARE signaling pathway.

Nobiletin Protects against Systemic Inflammation-Stimulated Memory Impairment via MAPK and NF-κB Signaling Pathways

Neuroinflammation has been intensively demonstrated to be related to various neurodegenerative diseases including Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and Alzheimer's disease (AD). A natural polymethoxylated flavone, nobiletin (NOB) has been reported to alleviate oxidative stress, insulin resistance, and obesity. In this study, we evaluated the protection effects of NOB on neuroinflammation and memory deficit. Three-month mice were administrated with NOB by oral gavage every day for 6 weeks (100 mg/kg/day); subsequently mice were injected intraperitoneally with lipopolysaccharide (LPS) for 7 days. Results of behavioral tests revealed that NOB dramatically ameliorated LPS-triggered memory deficit regarding synaptic dysfunctions and neuronal loss. Also, NOB suppressed the microglial activation and proinflammatory cytokine secretion, such as COX-2, IL-1β, TNF-α, and iNOS. Similarly, upon LPS stimulation, pretreatment NOB diminished the secretion of the proinflammatory cytokines in BV-2 microglia cells by exposure to LPS via modulating MAPKs, PI3K/AKT, and NF-κB signaling pathways. In addition, NOB alleviated LPS-amplified redox imbalance, disturbance of mitochondrial membrane potential (MMP), and dampening of the expression of protein related to mitochondrial respiration. The present study provides compelling evidence that NOB decreased LPS-stimulated neuroinflammation and memory impairment through maintaining cellular oxidative balance and blocking the NF-κB transcriptional pathway, illustrating that the nutritional compound NOB may serve as a potential approach to alleviate neuroinflammation-related diseases.

Carpesium divaricatum Sieb. & Zucc. Revisited: Newly Identified Constituents from Aerial Parts of the Plant and Their Possible Contribution to the Biological Activity of the Plant

Carpesium divaricatum Sieb. & Zucc. has a long history of use as both a medicinal and a food plant. However, except for terpenoids, its chemical constituents have remained poorly investigated. The composition of hydroalcoholic extract from aerial parts of C. divaricatum was analyzed by HPLC-DAD-MSⁿ, revealing the presence of numerous caffeic acid derivatives that were formerly unknown constituents of the plant. In all, 17 compounds, including commonly found chlorogenic acids and rarely occurring butyryl and methylbutyryl tricaffeoylhexaric acids, were tentatively identified. Fractionation of lipophilic extract from cultivated shoots led to the isolation of 12-oxo-phytodienoic acid (12-OPDA), which is a newly identified constituent of the plant. The compound, at concentrations of 0.5, 1.0, and 2.5 μM, significantly reduced IL-8, IL-1β, TNFα, and CCL2 excretion by lipopolysaccharide (LPS)-stimulated human neutrophils. Reactive oxygen species (ROS) production induced by f-MLP was also significantly diminished in the neutrophils pretreated by 12-OPDA. The newly identified constituents of the plant seem to be partly responsible for its pharmacological activity and elevate the value of C. divaricatum as a potential functional food.

Anti-Fatigue Activity of Aqueous Extracts of Sonchus arvensis L. in Exercise Trained Mice

Sonchus arvensis L. is a nutritious vegetable and herbal medicine that is consumed worldwide. The aim of this study was to evaluate the anti-fatigue effects and underlying effects of aqueous extract of Sonchus arvensis L. (SA). Male C57BL/6 mice from four groups designated vehicle, exercise, exercise with low dose (250 mg/kg) or high dose of SA (500 mg/kg), were trained by swimming exercise and orally administrated with SA every other day for 28 days. The anti-fatigue activity was determined by exhaustive swimming test, as well as the muscle structure, levels of blood hemoglobin, and metabolites including lactate and urea nitrogen. SA alleviated mice fatigue behaviors by eliminating metabolites, while improving muscle structure and hemoglobin levels. Moreover, SA enhanced glycogen synthesis of liver but not muscle via increasing GCK and PEPCK gene expressions. Importantly, SA improved antioxidant enzymes expression and activities in both liver and muscle, which was possibly related to its primary components polysaccharides and the antioxidant components including chlorogenic acid, luteolin, and chicoric acid. Taken together, the anti-fatigue effects of SA could be partly explained by its antioxidant activity and mediating effects on glycogen synthesis and metabolites elimination. Therefore, SA could be a potential nutraceutical for improving exercise performance and alleviating physical fatigue.

Simvastatin prevents and ameliorates depressive behaviors via neuroinflammatory regulation in mice

BACKGROUND

Statins play a beneficial role in the treatment of coronary artery disease and are widely prescribed to prevent hypercholesterolemia. Previous studies have demonstrated that statins also have anti-inflammatory and immunomodulatory properties, and these are being explored for potential benefits in depression. However, the role of statins in the treatment of depression has not been well examined.

METHODS

We investigated the effects of simvastatin on depressive behaviors and neuroinflammation in lipopolysaccharide (LPS) and chronic mild stress (CMS) induced depression model in mice. Sucrose preference test (SPT), forced swimming test (FST), novelty-suppressed feeding test (NSFT) were used to detect the depressive behaviors. The microglial activation was detected by immunohistochemistry analysis and the pro-inflammatory cytokines expressions including IL-1β, TNF-α and IL-6 were examined by Western blot analysis.

RESULTS

Our data indicated that oral administration of simvastatin at 20 mg/kg significantly prevented and ameliorated depressive behaviors reflected by better performance in the SPT, FST and NSFT. Moreover, simvastatin markedly prevented and ameliorated LPS and CMS-induced neuroinflammation, as shown by the suppressed activation of microglia in hippocampus and decreased hippocampal pro-inflammatory cytokines expressions including IL-1β, TNF-α, IL-6, which might be mediated via the inhibition of NF-κB pathway, as shown by the decreased nuclear NF-κB p65 expression.

LIMITATIONS

The interpretation of the evidence of a positive treatment effect of simvastatin on the depressive manifestations, multifaceted etiology of depression, and confirmation of this finding from animal models to humans is needed.

CONCLUSION

These results suggest that simvastatin has the potential to be employed as a therapy for depression associated with neuroinflammation.

Tea polyphenols direct Bmal1-driven ameliorating of the redox imbalance and mitochondrial dysfunction in hepatocytes

Circadian rhythms are intimately linked to cellular redox status homeostasis via the regulation of mitochondrial function. Tea polyphenols (TP) are nutraceuticals that possess powerful antioxidant properties, especially ameliorating oxidative stress. The objective of this study was to investigate whether circadian clock is involved in the protection effect of TP on oxidative stress cell models. TP ameliorate H2O2-triggered relatively shallow daily oscillations and phase shift of circadian clock genes transcription and protein expression. Meanwhile, TP attenuate H2O2-stimulated excessive secretions of reactive oxygen species (ROS) and restore the depletions of mitochondrial function in a Bmal1-dependent manner. Furthermore, TP treatment accelerates nuclear translocation of Nrf2 and modulates the downstream expressions of antioxidant enzymes. Intriguingly, knockdown of Bmal1 notably blocked Nrf2/ARE/HO-1 redox-sensitive transcription pathway. Our study revealed that TP, as a Bmal1-enhancing natural compound, alleviated redox imbalance via strengthening Keap1/Nrf2 antioxidant defense pathway and ameliorating mitochondrial dysfunction in a Bmal1-dependent manner.

Luteolin-mediated PI3K/AKT/Nrf2 signaling pathway ameliorates inorganic mercury-induced cardiac injury

Inorganic mercury is a toxic metal of worldwide concern, and causes serious cardiac injury. However, effective treatment for cardiac injury induced by mercuric chloride (HgCl₂) has not been fully identified. Luteolin (Lut) is a novel natural antioxidant. This study aimed to investigate the role of Lut on HgCl₂-induced cardiac injury. Male Wistar rats were randomly assigned to 4 groups, control, Lut (80 mg/kg intragastrically), HgCl₂ (80 mg/L, in drinking water), and HgCl₂ + Lut groups. The results indicated that Lut significantly ameliorated cardiac histopathological damage, oxidative stress, and apoptosis induced by HgCl₂ in the rat heart. Furthermore, Lut evidently increased levels of phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), and nuclear factor-erythroid-2-related factor 2 (Nrf2) and its downstream proteins, and inhibited NF-κB activation in the heart of rats treated by HgCl₂. Taken together, our findings suggest that activating PI3K/AKT/Nrf2 signaling pathway is involved in the protective effect of Lut against HgCl₂-induced cardiac damage.

Cichoric Acid Prevents Free-Fatty-Acid-Induced Lipid Metabolism Disorders via Regulating Bmal1 in HepG2 Cells

Cichoric acid (CA), a polyphenol component from Echinacea purpurea, exhibits preventive effects on liver lipid-metabolism disorders in obesity. This research aimed to determine the role of circadian rhythm signaling during the process of CA-attenuated lipid accumulation in hepatocytes. In the current study, CA treatments improved cell morphology changes and hepatic lipid levels, which were triggered by free fatty acids (2:1, oleate: palmitate) in a dose-dependent way. Besides, CA (200 μM) regulated the circadian rhythm expressions of clock genes and the relatively shallow daily oscillations. Moreover, silencing Bmal1 significantly blocked the p-Akt/Akt pathway to 80.1% ± 1.5% and the p-GSK3β/GSK3β pathway to 64.7% ± 2.8% ( p < 0.05). Furthermore, silencing Bmal1 elevated the expressions of FAS and ACC to 122.4% ± 5.6% and 114.9% ± 1.7% in protein levels ( p < 0.05) and to 166.5% ± 18.5% and 131.4% ± 5.5% in mRNA levels ( p < 0.05). Therefore, our results demonstrated that CA has a Bmal1 resistance to lipid accumulation by enhancing the Akt/GSK3β signaling pathways and modulating the downstream expressions related to lipid metabolism, which indicated that CA might be useful as a natural and promising nonalcoholic fatty liver diseases (NAFLD) modulator.

Neuroprotective action of tea polyphenols on oxidative stress-induced apoptosis through the activation of the TrkB/CREB/BDNF pathway and Keap1/Nrf2 signaling pathway in SH-SY5Y cells and mice brain

Many studies have shown that oxidative stress is a major cause of cellular injuries in a variety of human diseases including cognitive impairment. Tea polyphenols (TPs), natural plant flavonoids found in tea plant leaves, possess the bioactivity to affect the pathogenesis of several chronic diseases via antioxidant associated mechanisms. However, the possible antioxidant and neuroprotective properties of TPs in the brain of mice housed in constant darkness and in H₂O₂-stimulated SH-SY5Y cells are yet to be elucidated. In this study, pretreatment with TPs markedly attenuated H₂O₂-elicited cell viability loss and mitochondrial dysfunction, suppressed the induced apoptosis and reduced the elevated levels of intracellular ROS and H₂O₂. Additionally, TPs modulate the nuclear translocation of Nrf2 and the TrkB/CREB/BDNF signaling pathway by provoking the PI3K/AKT pathway and thus, they transcriptionally regulate the downstream expression of antioxidant enzymes including HO-1, NQO-1, and BDNF in SH-SY5Y cells. Furthermore, an in vivo study revealed that housing mice in constant darkness, simulating shift work disruption in humans, notably affects the AKT/CREB/BDNF signal pathway and the nuclear translocation of Nrf2 and its downstream phase II detoxification enzymes in brain tissue. Remarkably, TP supplementation through drinking water eliminated these changes. These results suggest that TPs possess protective effects against oxidative stress-triggered cognitive impairment, which might be a potential nutritional preventive strategy for neurodegenerative diseases implicated with oxidative stress in shift workers.