Capsaicin attenuates LPS-induced inflammatory cytokine production by upregulation of LXRα

Capsaicin: pharmacological applications and prospects for drug designing

OBJECTIVES

A primary objective of this review is to summarize the evidence-based pharmacological applications of capsaicin, particularly its use to manage pain and treat various health conditions. A second goal of the review is to research how recent technological advances are improving the bioavailability and therapeutic index of capsaicin, as well as the development of novel capsaicin-mimetics that are able to enhance therapeutic responses in various human diseases.

METHODS

In the review, numerous human clinical trials and preclinical studies are examined to determine how effective, safe, and optimal dosages of capsaicin can be used in pain management and therapeutic applications. Furthermore, it discusses capsaicin's mechanisms of action, specifically its interactions with the transient receptor potential vanilloid 1 (TRPV1) channel. As a result of this review, the potential of nanotechnology systems for bypassing the limits of capsaicin's pungency is discussed. The review takes into account individual factors such as pain tolerance and skin sensitivity.

KEY FINDINGS

For topical applications, capsaicin is typically used in concentrations ranging from 0.025% to 0.1%, with higher concentrations being used under medical supervision for neuropathic pain. The formulation can come in the form of creams, gels, or patches, which provide sustained release over the course of time. A condition such as arthritis or neuropathy can be relieved with capsaicin as it depletes substance P from nerves. Neuropathy and osteoarthritis as well as musculoskeletal disorders have been treated successfully with this herbal medicine. A major mechanism through which capsaicin relieves pain is through activating TRPV1 channels, which induce calcium influx and neurotransmitter release. Additionally, it affects the transcription of genes related to pain modulation and inflammation, particularly when disease conditions or stress are present. There have been recent developments in technology to reduce capsaicin's pungency and improve its bioavailability, including nanotechnology.

CONCLUSIONS

It is proven that capsaicin is effective in pain management as well as a variety of therapeutic conditions because of its ability to deplete substance P and desensitize nerve endings. Although capsaicin is highly pungent and associated with discomfort, advancements in delivery technologies and the development of capsaicin-mimetics promise improved therapeutic outcomes. There is a great deal of complexity in the pharmacological action of capsaicin due to its interaction with TRPV1 channels and its ability to affect gene transcription. There is a need for further research and development in order to optimize capsaicin's clinical applications and to enhance its therapeutic index in a variety of human diseases.

Capsaicin Improves Systemic Inflammation, Atherosclerosis, and Macrophage-Derived Foam Cells by Stimulating PPAR Gamma and TRPV1 Receptors

BACKGROUND

Capsaicin, a bioactive compound found in peppers, is recognized for its anti-inflammatory, antioxidant, and anti-lipidemic properties. This study aimed to evaluate the effects of capsaicin on atherosclerosis progression.

METHODS

Apolipoprotein E knockout mice and their C57BL/6 controls were utilized to assess blood lipid profile, inflammatory status, and atherosclerotic lesions. We also examined the influence of capsaicin on cholesterol influx and efflux, and the role of TRPV1 and PPARγ signaling pathways in bone marrow-derived macrophages.

RESULTS

Capsaicin treatment reduced weight gain, visceral adiposity, blood triglycerides, and total and non-HDL cholesterol. These improvements were associated with a reduction in atherosclerotic lesions in the aorta and carotid. Capsaicin also improved hepatic oxidative and inflammatory status. Systemic inflammation was also reduced, as indicated by reduced leukocyte rolling and adhesion on the mesenteric plexus. Capsaicin decreased foam cell formation by reducing cholesterol influx through scavenger receptor A and increasing cholesterol efflux via ATP-binding cassette transporter A1, an effect primarily linked to TRPV1 activation.

CONCLUSIONS

These findings underscore the potential of capsaicin as a promising agent for atherosclerosis prevention, highlighting its comprehensive role in modulating lipid metabolism, foam cell formation, and inflammatory responses.

Ginsenoside Rb1 alleviates lipopolysaccharide-induced inflammation in human dental pulp cells via the PI3K/Akt, NF-κB, and MAPK signalling pathways

AIM

Among numerous constituents of Panax ginseng, a constituent named Ginsenoside Rb1 (G-Rb1) has been studied to diminish inflammation associated with diseases. This study investigated the anti-inflammatory properties of G-Rb1 on human dental pulp cells (hDPCs) exposed to lipopolysaccharide (LPS) and aimed to determine the underlying molecular mechanisms.

METHODOLOGY

The KEGG pathway analysis was performed after RNA sequencing in G-Rb1- and LPS-treated hDPCs. Reverse-transcription polymerase chain reaction (RT-PCR) and western blot analysis were used for the assessment of cell adhesion molecules and inflammatory cytokines. Statistical analysis was performed with one-way ANOVA and the Student-Newman-Keuls test.

RESULTS

G-Rb1 did not exhibit any cytotoxicity within the range of concentrations tested. However, it affected the levels of TNF-α, IL-6 and IL-8, as these showed reduced levels with exposure to LPS. Additionally, less mRNA and protein expressions of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were shown. With the presence of G-Rb1, decreased levels of PI3K/Akt, phosphorylated IκBα and p65 were also observed. Furthermore, phosphorylated ERK and JNK by LPS were diminished within 15, 30 and 60 min of G-Rb1 exposure; however, the expression of non-phosphorylated ERK and JNK remained unchanged.

CONCLUSIONS

G-Rb1 suppressed the LPS-induced increase of cell adhesion molecules and inflammatory cytokines, while also inhibiting PI3K/Akt, phosphorylation of NF-κB transcription factors, ERK and JNK of MAPK signalling in hDPCs.

Natural products in atherosclerosis therapy by targeting PPARs: a review focusing on lipid metabolism and inflammation

Inflammation and dyslipidemia are critical inducing factors of atherosclerosis. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors and control the expression of multiple genes that are involved in lipid metabolism and inflammatory responses. However, synthesized PPAR agonists exhibit contrary therapeutic effects and various side effects in atherosclerosis therapy. Natural products are structural diversity and have a good safety. Recent studies find that natural herbs and compounds exhibit attractive therapeutic effects on atherosclerosis by alleviating hyperlipidemia and inflammation through modulation of PPARs. Importantly, the preparation of natural products generally causes significantly lower environmental pollution compared to that of synthesized chemical compounds. Therefore, it is interesting to discover novel PPAR modulator and develop alternative strategies for atherosclerosis therapy based on natural herbs and compounds. This article reviews recent findings, mainly from the year of 2020 to present, about the roles of natural herbs and compounds in regulation of PPARs and their therapeutic effects on atherosclerosis. This article provides alternative strategies and theoretical basis for atherosclerosis therapy using natural herbs and compounds by targeting PPARs, and offers valuable information for researchers that are interested in developing novel PPAR modulators.

Evaluation of binding mechanism of dietary phytochemical, capsaicin, with human transferrin: targeting neurodegenerative diseases therapeutics

Human transferrin (htf) plays a crucial role in regulating the balance of iron within brain cells; any disruption directly contributes to the development of Neurodegenerative Diseases (NDs) and other related pathologies, especially Alzheimer's Disease (AD). In recent times, a transition towards natural compounds is evident to treat diseases and this shift is mainly attributed to their broad therapeutic potential along with minimal side effects. Capsaicin, a natural compound abundantly found in red and chili peppers, possess neuroprotective potential. The current work targets to decipher the interaction mechanism of capsaicin with htf using experimental and computational approaches. Molecular docking analysis revealed that capsaicin occupies the iron binding pocket of htf, with good binding affinity. Further, the binding mechanism was investigated atomistically using Molecular dynamic (MD) simulation approach. The results revealed no significant alterations in the structure of htf implying the stability of the complex. In silico observations were validated by fluorescence binding assay. Capsaicin binds to htf with a binding constant (K) of 3.99 × 106 M-1, implying the stability of the htf-capsaicin complex. This study lays a platform for potential applications of capsaicin in treatment of NDs in terms of iron homeostasis.

The preventive effects of Lactobacillus casei 03 on Escherichia coli-induced mastitis in vitro and in vivo

BACKGROUND

Lactobacillus casei possesses many kinds of bioactivities, such as anti-inflammation and anti-oxidant, and has been applied to treating multiple inflammatory diseases. However, its role in mastitis prevention has remained ambiguous.

METHODS

This study aimed to examine the mechanisms underlying the preventive effects of L. casei 03 against E. coli- mastitis utilizing bovine mammary epithelial cells (BMECs) and a mouse model.

RESULTS

In vitro assays revealed pretreatment with L. casei 03 reduced the apoptotic ratio and the mRNA expression levels of IL1β, IL6 and TNFα and suppressed phosphorylation of p65, IκBα, p38, JNK and ERK in the NF-κB signaling pathway and MAPK signaling pathway. Furthermore, in vivo tests indicated that intramammary infusion of L. casei 03 relieved pathological changes, reduced the secretion of IL1β, IL6 and TNFα and MPO activity in the mouse mastitis model.

CONCLUSIONS

These data suggest that L. casei 03 exerts protective effects against E. coli-induced mastitis in vitro and in vivo and may hold promise as a novel agent for the prevention and treatment of mastitis.

Bioactives and their roles in bone metabolism of osteoarthritis: evidence and mechanisms on gut-bone axis

Bioactives significantly modify and maintain human health. Available data suggest that Bioactives might play a beneficial role in chronic inflammatory diseases. Although promised, defining their mechanisms and opting to weigh their benefits and limitations is imperative. Detailed mechanisms by which critical Bioactives, including probiotics and prebiotics such as dietary lipids (DHA, EPA, alpha LA), vitamin D, polysaccharides (fructooligosaccharide), polyphenols (curcumin, resveratrol, and capsaicin) potentially modulate inflammation and bone metabolism is limited. Certain dietary bioactive significantly impact the gut microbiota, immune system, and pain response via the gut-immune-bone axis. This narrative review highlights a recent update on mechanistic evidence that bioactive is demonstrated demonstrated to reduce osteoarthritis pathophysiology.

Therapeutic Potential of Capsaicin in Various Neurodegenerative Diseases with Special Focus on Nrf2 Signaling

Neurodegenerative disease is mainly characterized by the accumulation of misfolded proteins, contributing to mitochondrial impairments, increased production of proinflammatory cytokines and reactive oxygen species, and neuroinflammation resulting in synaptic loss and neuronal loss. These pathophysiological factors are a serious concern in the treatment of neurodegenerative diseases. Based on the symptoms of various neurodegenerative diseases, different treatments are available, but they have serious side effects and fail in clinical trials, too. Therefore, treatments for neurodegenerative diseases are still a challenge at present. Thus, it is important to study an alternative option. Capsaicin is a naturally occurring alkaloid found in capsicum. Besides the TRPV1 receptor activator in nociception, capsaicin showed a protective effect in brain-related disorders. Capsaicin also reduces the aggregation of misfolded proteins, improves mitochondrial function, and decreases ROS generation. Its antioxidant role is due to increased expression of an nrf2-mediated signaling pathway. Nrf2 is a nuclear erythroid 2-related factor, a transcription factor, which has a crucial role in maintaining the normal function of mitochondria and the cellular defense system against oxidative stress. Intriguingly, Nrf2 mediated pathway improved the upregulation of antioxidant genes and inhibition of microglial-induced inflammation, improved mitochondrial resilience and functions, leading to decreased ROS in neurodegenerative conditions, suggesting that Nrf2 activation could be a better therapeutic approach to target pathophysiology of neurodegenerative disease. Therefore, the present review has evaluated the potential role of capsaicin as a pharmacological agent for the treatment and management of various neurodegenerative diseases via the Nrf2-mediated signaling pathway.

Preparation of capsaicin-loaded ultrafine fiber film and its application in the treatment of oral ulcers in rats

A drug-loaded diaphragm is an easy-to-use and effective drug delivery system that is often used to treat mouth ulcers. In this study, an ultrafine fiber film loaded with capsaicin was successfully prepared using the electrospinning technology. poly-L-lactic acid and gelatin were selected as the matrix materials to form the composite fiber, and trifluoroethanol was used as a co-solvent for poly-L-lactic acid, gelatin and capsaicin to prepare the spinning solution, which was simple to fabricate. The prepared fiber films were characterized based on their microscopic morphology and tested to derive their mechanical properties. Thereafter, the capsaicin release behavior of the film was investigated. In vitro experiments revealed certain anti-inflammatory and antibacterial abilities while animal experiments revealed that the capsaicin-loaded ultrafine fiber film could promote the healing of oral ulcers in rats. Healing of the tongue tissue in rats administered 10% capsaicin-loaded fiber film was found to be better than that in rats administered the commercial dexamethasone patch. Overall, this development strategy may prove to be promising for the development of oral ulcer patch formulations.

A Systematic Review of the Effects of Capsaicin on Alzheimer's Disease

Alzheimer's Disease (AD) is a progressive neurodegenerative disorder characterised by cognitive impairment, and amyloid-β plaques and neurofibrillary tau tangles at neuropathology. Capsaicin is a spicy-tasting compound found in chili peppers, with anti-inflammatory, antioxidant, and possible neuroprotective properties. Capsaicin intake has been associated with greater cognitive function in humans, and attenuating aberrant tau hyperphosphorylation in a rat model of AD. This systematic review discusses the potential of capsaicin in improving AD pathology and symptoms. A systematic analysis was conducted on the effect of capsaicin on AD-associated molecular changes, cognitive and behaviour resulting in 11 studies employing rodents and/or cell cultures, which were appraised with the Cochrane Risk of Bias tool. Ten studies showed capsaicin attenuated tau deposition, apoptosis, and synaptic dysfunction; was only weakly effective on oxidative stress; and had conflicting effects on amyloid processing. Eight studies demonstrated improved spatial and working memory, learning, and emotional behaviours in rodents following capsaicin treatment. Overall, capsaicin showed promise in improving AD-associated molecular, cognitive, and behavioural changes in cellular and animal models, and further investigations are recommended to test the readily available bioactive, capsaicin, to treat AD.

Capsaicin attenuates excitotoxic-induced neonatal brain injury and brain mast cell-mediated neuroinflammation in newborn rats

Excitotoxicity and neuroinflammation are key contributors to perinatal brain injuries. Capsaicin, an active ingredient of chili peppers, is a potent exogenous agonist for transient receptor potential vanilloid 1 receptors. Although the neuroprotective and anti-inflammatory effects of capsaicin are well-documented, its effects on excitotoxic-induced neonatal brain injury and neuroinflammation have not previously been investigated. The aim of this study was to investigate the effects of capsaicin on brain damage, brain mast cells, and inflammatory mediators in a model of ibotenate-induced excitotoxic brain injury in neonatal rats. P5 rat-pups were intraperitoneally injected with vehicle, 0.2-, 1-, and 5-mg/kg doses of capsaicin, or the NMDA (N-methyl-d-aspartate) receptor antagonist MK-801 (dizocilpine), 30 min before intracerebral injection of 10 μg ibotenate. The naive-control group received no substance administration. The rat pups were sacrificed one or five days after ibotenate injection. Levels of activin A and interleukin (IL)-1β, IL-6, and IL-10 in brain tissue were measured using the enzyme-linked immunosorbent assay method. Cortex and white matter thicknesses, white matter lesion size, and mast cells were evaluated in brain sections stained with cresyl-violet or toluidine-blue. Capsaicin improved ibotenate-induced white matter lesions and cerebral white and gray matter thicknesses in a dose-dependent manner. In addition, it suppressed the degranulation and increased number of brain mast cells induced by ibotenate. Capsaicin also reduced the excitotoxic-induced production of neuronal survival factor activin A and of the pro-inflammatory cytokines IL-1β, and IL-6 in brain tissue. However, IL-10 levels were not altered by the treatments. MK-801, as a positive control, reversed all these ibotenate-induced changes, further confirming the success of the model. Our findings provide, for the first time, evidence for the therapeutic effects of capsaicin against excitotoxic-induced neonatal brain injury and brain mast cell-mediated neuroinflammation. Capsaicin may therefore be a promising candidate in the prevention and/or reduction of neonatal brain damage.

Capsaicin protects against septic acute liver injury by attenuation of apoptosis and mitochondrial dysfunction

Capsaicin is the main pungent bioactive constituent in red chili with promising therapeutic properties due to its anti-oxidative and anti-inflammatory effects. No evidence exists on the beneficial effect of capsaicin on apoptosis and mitochondrial function in acute liver injury (ALI) under septic conditions. For inducing septic ALI, lipopolysaccharide (LPS, 50 μg/kg) and d-galactose (D-Gal, 400 mg/kg) was intraperitoneally injected and capsaicin was given orally at 5 or 20 mg/kg. Functional markers of liver function and mitochondrial dysfunction were determined as well as hepatic assessment of apoptotic, oxidative, and inflammatory factors. Capsaicin at the higher dose appropriately decreased serum level of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in addition to reducing hepatic level of malondialdehyde (MDA), reactive oxygen species (ROS), nitrite, NF-kB, TLR4, IL-1β, TNF-α, caspase 3, DNA fragmentation and boosting sirtuin 1, Nrf2, superoxide dismutase (SOD) activity, and heme oxygenase (HO-1). These beneficial effects of capsaicin were associated with reversal and/or improvement of gene expression for pro-apoptotic Bax, anti-apoptotic Bcl2, mitochondrial and metabolic regulators PGC-1α, sirtuin 1, and AMPK, and inflammation-associated factors. Additionally, capsaicin exerted a hepatoprotective effect, as revealed by its reduction of liver histopathological changes. These findings evidently indicate hepatoprotective property of capsaicin under septic conditions that can be attributed to its down-regulation of oxidative and inflammatory processes besides its potential to attenuate mitochondrial dysfunction and apoptosis.

Spices and Biomarkers of COVID-19: A Mechanistic and Therapeutic Perspective

In the face of the COVID-19 pandemic, many people around the world have increased their healthy behaviors to prevent transmission of the virus and potentially improve their immune systems. Therefore, the role of diet and food compounds such as spices with bioactive and antiviral properties may be important in these efforts. In this chapter, we review the efficacy of spices such as turmeric (curcumin), cinnamon, ginger, black pepper, saffron, capsaicin, and cumin by investigating the effects of these compounds of COVID-19 disease severity biomarkers.

Minimal Influence of Cayenne Pepper on the Human Gastrointestinal Microbiota and Intestinal Inflammation in Healthy Adult Humans-A Pilot Study

Diet impacts human gut microbial composition. Phytochemicals in cayenne pepper (CP), such as capsaicin, have anti-inflammatory properties and alter bacterial growth in vitro. However, the evidence that CP impacts the human microbiota and intestinal inflammation in free-living adults is lacking. Thus, the objective of this randomized cross-over study was to determine the influence of CP on human gut microbiota and intestinal inflammation in vivo. A total of 29 participants were randomly allocated to consume two 250 mL servings of tomato juice plus 1.8 g of CP each day or juice only for 5 days before crossing over to the other study arm. Fecal samples were analyzed. CP reduced Oscillibacter and Phascolarctobacterium but enriched Bifidobacterium and Gp6. When stratified by BMI (body mass index), only the increase in Gp6 was observed in all BMI groups during CP treatment. Stool concentrations of lipocalin-2 and calprotectin were similar regardless of CP treatment. However, lipocalin-2 and calprotectin levels were positively correlated in samples taken after CP consumption. Neither lipocalin-2 nor calprotectin levels were related to gut microbial composition. In conclusion, in healthy adult humans under typical living conditions, consumption of CP minimally influenced the gut microbiota and had little impact on intestinal inflammation.

Tetramethylpyrazine and Paeoniflorin Synergistically Attenuate Cholesterol Efflux in Macrophage Cells via Enhancing ABCA1 and ABCG1 Expression

The formation of foam cells is a characteristic of the occurrence and development of atherosclerosis. ATP-binding cassette subfamily A1 and G1 (ABCA1 and ABCG1) and scavenger receptor B1 (SR-B1) play critical roles in promoting intracellular cholesterol efflux to high-density lipoprotein (HDL) or apolipoprotein A1 (apoA1). We attempted to test the effect of the tetramethylpyrazine-paeoniflorin pair (TP) on cholesterol outflow in foam cells derived from macrophages. In this study, RAW264.7 macrophages were treated with 80 mg/L oxidized low-density lipoprotein (ox-LDL) for 24 h to obtain foam cells. Then they were intervened with TP (tetramethylpyrazine 40 ug/ml plus paeoniflorin 80 ug/ml) for additional 24 h. The distribution of cholesterol in foam cells was evaluated by oil red O staining. The contents of total cholesterol (TC) and free cholesterol (FC) were assessed with commercial kits. Fluorescent imaging was observed with a fluorescent inverted microscope. The capacity of cholesterol efflux was measured with a fluorescent plate reader, and the transcript and protein levels of ABCA1, ABCG1, and SR-B1 were detected by Western blot and quantitative polymerase chain reactions (Q-PCRs). Cytokines in the medium were detected by ELISA and adjusted by total cellular proteins. The results showed that TP decreased ox-LDL-induced cholesterol deposition and foam cell formation by promoting cholesterol efflux to apoA1, which was related to the upregulation of ABCA1 and ABCG1. Moreover, TP decreased the secretion of ox-LDL-induced tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), and monocyte chemotactic protein-1 (MCP-1), an important profoam cell cytokine in atherosclerosis.

Capsaicin: A Two-Decade Systematic Review of Global Research Output and Recent Advances Against Human Cancer

Capsaicin (8-methyl-N-vanillyl-6-nonenamide) is one of the most important natural products in the genus Capsicum. Due to its numerous biological effects, there has been extensive and increasing research interest in capsaicin, resulting in increased scientific publications in recent years. Therefore, an in-depth bibliometric analysis of published literature on capsaicin from 2001 to 2021 was performed to assess the global research status, thematic and emerging areas, and potential insights into future research. Furthermore, recent research advances of capsaicin and its combination therapy on human cancer as well as their potential mechanisms of action were described. In the last two decades, research outputs on capsaicin have increased by an estimated 18% per year and were dominated by research articles at 93% of the 3753 assessed literature. In addition, anti-cancer/pharmacokinetics, cytotoxicity, in vivo neurological and pain research studies were the keyword clusters generated and designated as thematic domains for capsaicin research. It was evident that the United States, China, and Japan accounted for about 42% of 3753 publications that met the inclusion criteria. Also, visibly dominant collaboration nodes and networks with most of the other identified countries were established. Assessment of the eligible literature revealed that the potential of capsaicin for mitigating cancer mainly entailed its chemo-preventive effects, which were often linked to its ability to exert multi-biological effects such as anti-mutagenic, antioxidant and anti-inflammatory activities. However, clinical studies were limited, which may be related to some of the inherent challenges associated with capsaicin in the limited clinical trials. This review presents a novel approach to visualizing information about capsaicin research and a comprehensive perspective on the therapeutic significance and applications of capsaicin in the treatment of human cancer.

Lactobacillus plantarum 17-5 attenuates Escherichia coli-induced inflammatory responses via inhibiting the activation of the NF-κB and MAPK signalling pathways in bovine mammary epithelial cells

Background

Mastitis is one of the most prevalent diseases and causes considerable economic losses in the dairy farming sector and dairy industry. Presently, antibiotic treatment is still the main method to control this disease, but it also brings bacterial resistance and drug residue problems. Lactobacillus plantarum (L. plantarum) is a multifunctional probiotic that exists widely in nature. Due to its anti-inflammatory potential, L. plantarum has recently been widely researched in complementary therapies for various inflammatory diseases. In this study, the apoptotic ratio, the expression levels of various inflammatory mediators and key signalling pathway proteins in Escherichia coli-induced bovine mammary epithelial cells (BMECs) under different doses of L. plantarum 17–5 intervention were evaluated.

Results

The data showed that L. plantarum 17–5 reduced the apoptotic ratio, downregulated the mRNA expression levels of TLR2, TLR4, MyD88, IL1β, IL6, IL8, TNFα, COX2, iNOS, CXCL2 and CXCL10, and inhibited the activation of the NF-κB and MAPK signalling pathways by suppressing the phosphorylation levels of p65, IκBα, p38, ERK and JNK.

Conclusions

The results proved that L. plantarum 17–5 exerted alleviative effects in Escherichia coli-induced inflammatory responses of BMECs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03355-9.

Baicalein inhibits macrophage lipid accumulation and inflammatory response by activating the PPARγ/LXRα pathway

Lipid accumulation and inflammatory response are two major risk factors for atherosclerosis. Baicalein, a phenolic flavonoid widely used in East Asian countries, possesses a potential atheroprotective activity. However, the underlying mechanisms remain elusive. This study was performed to explore the impact of baicalein on lipid accumulation and inflammatory response in THP-1 macrophage-derived foam cells. Our results showed that baicalein up-regulated the expression of ATP binding cassette transporter A1 (ABCA1), ABCG1, liver X receptor α (LXRα), and peroxisome proliferator-activated receptor γ (PPARγ), promoted cholesterol efflux, and inhibited lipid accumulation. Administration of baicalein also reduced the expression and secretion of TNF-α, IL-1β, and IL-6. Knockdown of LXRα or PPARγ with siRNAs abrogated the effects of baicalein on ABCA1 and ABCG1 expression, cholesterol efflux, lipid accumulation as well as pro-inflammatory cytokine release. In summary, these findings suggest that baicalein exerts a beneficial effect on macrophage lipid accumulation and inflammatory response by activating the PPARγ/LXRα signaling pathway.

The protective effect of licochalcone A against inflammation injury of primary dairy cow claw dermal cells induced by lipopolysaccharide

Laminitis is one of the most important and intractable diseases in dairy cows, which can lead to enormous economic losses. Although many scholars have conducted a large number of studies on laminitis, the therapeutic test of medicinal plants in vitro is really rare. Licochalcone A is proved to possess anti-inflammatory and anti-oxidant properties. But the effect of licochalcone A on LPS-induced inflammatory claw dermal cells has not been discovered yet. In this study, the primary dairy cow claw dermal cells were treated with gradient concentrations of licochalcone A (1, 5, 10 µg/mL) in the presence of 10 µg/mL lipopolysaccharides (LPS). The results indicated that licochalcone A reduced the concentrations of inflammation mediators (TNF-α, IL-1β and IL-6), increased the activity of SOD, reduced the levels of MDA and ROS, downregulated the mRNA expressions of TLR4 and MyD88, suppressed the protein levels of p-IκBα and p-p65, and upregulated the protein expression of PPARγ. In summary, licochalcone A protected dairy cow claw dermal cells against LPS-induced inflammatory response and oxidative stress through the regulation of TLR4/MyD88/NF-κB and PPARγ signaling pathways.

Capsaicin and Its Effect on Exercise Performance, Fatigue and Inflammation after Exercise

Capsaicin (CAP) activates the transient receptor potential vanilloid 1 (TRPV1) channel on sensory neurons, improving ATP production, vascular function, fatigue resistance, and thus exercise performance. However, the underlying mechanisms of CAP-induced ergogenic effects and fatigue-resistance, remain elusive. To evaluate the potential anti-fatigue effects of CAP, 10 young healthy males performed constant-load cycling exercise time to exhaustion (TTE) trials (85% maximal work rate) after ingestion of placebo (PL; fiber) or CAP capsules in a blinded, counterbalanced, crossover design, while cardiorespiratory responses were monitored. Fatigue was assessed with the interpolated twitch technique, pre-post exercise, during isometric maximal voluntary contractions (MVC). No significant differences (p > 0.05) were detected in cardiorespiratory responses and self-reported fatigue (RPE scale) during the time trial or in TTE (375 ± 26 and 327 ± 36 s, respectively). CAP attenuated the reduction in potentiated twitch (PL: -52 ± 6 vs. CAP: -42 ± 11%, p = 0.037), and tended to attenuate the decline in maximal relaxation rate (PL: -47 ± 33 vs. CAP: -29 ± 68%, p = 0.057), but not maximal rate of force development, MVC, or voluntary muscle activation. Thus, CAP might attenuate neuromuscular fatigue through alterations in afferent signaling or neuromuscular relaxation kinetics, perhaps mediated via the sarco-endoplasmic reticulum Ca2+ ATPase (SERCA) pumps, thereby increasing the rate of Ca2+ reuptake and relaxation.

Qihuzha granule attenuated LPS-induced acute spleen injury in mice via Src/MAPK/Stat3 signal pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Qihuzha granule (QHZG), is one of traditional Chinese patent medicines composed of eleven edible medicinal plant, which has been used in the clinic for the treatment of indigestion and anorexia in children caused by deficiency of the spleen and stomach. Yet it is noteworthy that QHZG has therapeutic effect on recurrent respiratory tract infection (RRTI) in children. However, its potential molecular mechanisms remained unclear.

AIM OF THE STUDY

The aim of this study was to investigate the therapeutic effect and potential mechanism of QHZG on lipopolysaccharide (LPS) induced acute spleen injury.

MATERIALS AND METHODS

The acute spleen injury model was induced by intraperitoneal injection of LPS (10 mg/kg) and safe doses of QHZG was administered by gavage once a day for 23 days before LPS treatment. Serum inflammatory cytokines including interleukin-2 (IL-2), IL-1β, IFN-γ, and tumor necrosis factor-α (TNF-α) were tested by ELISA. Related protein levels were detected by Western blotting. Hematoxylin-eosin (HE) staining was employed to observe the histological alterations. The distribution of macrophages and neutrophils in the mouse spleen was examined by immunofluorescence analysis.

RESULTS

QHZG pretreatment significantly abolished the increased secretion of cytokines such as interleukin-2 (IL-2), IL-1β, IFN-γ, and tumor necrosis factor-α (TNF-α), which were attributable to LPS treatment. Immunofluorescence staining and Histological analysis of spleen tissue revealed the protective effect of QHZG against LPS-induced acute spleen injury in mice. Further study indicated that pretreatment with QHZG significantly inhibited LPS-induced phosphorylation of Src. Accordingly, the increased phosphorylation of Src downstream components (JNK, ERK, P38 and STAT3) induced by LPS was remarkably diminished by QHZG, suggesting the involvement of Src/MAPK/STAT3 pathway in the inhibitory effects of QHZG on spleen injury in mice.

CONCLUSION

Our study demonstrated that QHZG protected mice from LPS-induced acute spleen injury via inhibition of Src/MAPK/Stat3 signal pathway. These results suggested that QHZG might serve as a new drug for the treatment of LPS-stimulated spleen injury.

Signaling Targets Related to Antiobesity Effects of Capsaicin: A Scoping Review

The search for new antiobesogenic agents is increasing because of the current obesity pandemic. Capsaicin (Caps), an exogenous agonist of the vanilloid receptor of transient potential type 1 (TRPV1), has shown promising results in the treatment of obesity. This scoping review aims to verify the pathways mediating the effects of Caps in obesity and the different methods adopted to identify these pathways. The search was carried out using data from the EMBASE, MEDLINE (PubMed), Web of Science, and SCOPUS databases. Studies considered eligible evaluated the mechanisms of action of Caps in obesity models or cell types involved in obesity. Nine studies were included and 100% (n = 6) of the in vivo studies showed a high risk of bias. Of the 9 studies, 66.6% (n = 6) administered Caps orally in the diet and 55.5% (n = 5) used a concentration of Caps of 0.01% in the diet. In vitro, the most tested concentration was 1 μM (88.9%; n = 8). Capsazepine was the antagonist chosen by 66.6% (n = 6) of the studies. Seven studies (77.8%) linked the antiobesogenic effects of Caps to TRPV1 activation and 3 (33.3%) indicated peroxisome proliferator-activated receptor (PPAR) involvement as an upstream connection to TRPV1, rather than a direct metabolic target of Caps. The main secondary effects of Caps were lower weight gain (33.3%; n = 3) or loss (22.2%; n = 2), greater improvement in lipid profile (33.3%; n = 3), lower white adipocyte adipogenesis (33.3%; n = 3), browning process activation (44.4%; n = 4), and higher brown adipocyte activity (33.3%; n = 3) compared with those of the control treatment. Some studies have shown that PPAR agonists modulate TRPV1 activity, and no study has evaluated the simultaneous antagonism of these 2 receptors. Consequently, further studies are necessary to elucidate the role of each of these signaling molecules in the antiobesogenic effects of Caps.

Optimal Extraction Process and In Vivo Anti-Inflammatory Evaluation of High Purity Oily Capsicum Oleoresin for Pharmaceutical Applications

Recently, plant-derived anti-inflammatory products have received an increasing attention from researchers due to their excellent in vivo activity with limited side effects. Therefore, the extraction of natural active compounds from the plant with high purity for use in anti-inflammatory formulations is required. In this study, oily Capsicum oleoresin (OCO) was extracted from Capsicum frutescens L. in ethanol by the ultrasound-assisted extraction technique, followed by a centrifugation step for a high purity OCO extract, which can be applied to develop anti-inflammatory formulations. The impact of various conditions (ethanol concentration, sonicating temperature, extraction time, solvent-to-sample ratio, and extraction repetition) on the efficiency of the extraction process was investigated. The results showed that the optimized conditions for the high yield of OCO were 95% ethanol, 50-60°C, 60 minutes, solvent-to-sample ratio of 5 : 1 ml/g, and one extraction repetition, followed by centrifuging at 5000 rpm in 2 hours. Then, the purity and in vivo anti-inflammatory activities of the obtained OCO was then determined by using the HPLC method and carrageenan-induced mice paw edema model, respectively. The purity of OCO was determined as 3.408 mg capsaicin per gram of Capsicum powder; meanwhile, its anti-inflammatory effect value was approximate to that of the commercial drug diclofenac after 48 hours of treatment. The high purity OCO prepared by this low-cost and ecofriendly extraction process would be a promising material for anti-inflammatory formulations.

COVID-19, cytokines, inflammation, and spices: How are they related?

BACKGROUND

Cytokine storm is the exaggerated immune response often observed in viral infections. It is also intimately linked with the progression of COVID-19 disease as well as associated complications and mortality. Therefore, targeting the cytokine storm might help in reducing COVID-19-associated health complications. The number of COVID-19 associated deaths (as of January 15, 2021; https://www.worldometers.info/coronavirus/) in the USA is high (1199/million) as compared to countries like India (110/million). Although the reason behind this is not clear, spices may have some role in explaining this difference. Spices and herbs are used in different traditional medicines, especially in countries such as India to treat various chronic diseases due to their potent antioxidant and anti-inflammatory properties.

AIM

To evaluate the literature available on the anti-inflammatory properties of spices which might prove beneficial in the prevention and treatment of COVID-19 associated cytokine storm.

METHOD

A detailed literature search has been conducted on PubMed for collecting information pertaining to the COVID-19; the history, origin, key structural features, and mechanism of infection of SARS-CoV-2; the repurposed drugs in use for the management of COVID-19, and the anti-inflammatory role of spices to combat COVID-19 associated cytokine storm.

KEY FINDINGS

The literature search resulted in numerous in vitro, in vivo and clinical trials that have reported the potency of spices to exert anti-inflammatory effects by regulating crucial molecular targets for inflammation.

SIGNIFICANCE

As spices are derived from Mother Nature and are inexpensive, they are relatively safer to consume. Therefore, their anti-inflammatory property can be exploited to combat the cytokine storm in COVID-19 patients. This review thus focuses on the current knowledge on the role of spices for the treatment of COVID-19 through suppression of inflammation-linked cytokine storm.

Capsaicin Attenuates Lipopolysaccharide-Induced Inflammation and Barrier Dysfunction in Intestinal Porcine Epithelial Cell Line-J2

Capsaicin is a spicy, highly pungent, colorless, vanilloid compound found in chili peppers with anti-inflammatory, antioxidant, anti-cancer, and analgesic properties. However, the protective effects of capsaicin on the pig intestine during inflammation are yet to be explored. This study investigated the effects of capsaicin on the gut inflammatory response, intestinal epithelial integrity, and gene expression level of nutrient transporters in a model of lipopolysaccharide (LPS)-induced inflammation in non-differentiated intestinal porcine epithelial cell line-J2 (IPEC-J2). The results showed that the pre-treatment of cells with capsaicin (100 μM) significantly decreased the gene expression and secretion of proinflammatory cytokines induced by LPS through Toll-like receptor 4 (TLR4)/NF-κB signaling pathway. In addition, pre-treatment of cells with capsaicin also increased both gene and protein abundance of tight junction proteins. Furthermore, pre-treatment cells with capsaicin significantly increased trans-epithelial electrical resistance (TEER) and decreased permeability of fluorescein isothiocyanate-dextran (FD4) from the apical side to the basolateral side compared with the control (P < 0.05). Additionally, pre-treatment of cells with capsaicin upregulated the mRNA abundance of nutrients transporters such as Na⁺/glucose cotransporter 1 (SGLT1). These results suggested that capsaicin could attenuate LPS-induced inflammation response through TLR4/NF-κB pathway and improve barrier integrity and glucose absorption.

Angelica polysaccharide attenuates LPS-induced inflammation response of primary dairy cow claw dermal cells via NF-κB and MAPK signaling pathways

Background

Laminitis, an inflammation of the claw laminae, is one of the major causes of bovine lameness, which can lead to enormous economic losses and animal welfare problems in dairy farms. Angelica polysaccharide (AP) is proved to possess anti-inflammatory properties. But the role of AP on inflammatory response of the claw dermal cells has not been reported. The aim of this study was to investigate the anti-inflammatory effects of AP on lipopolysaccharide (LPS)-induced primary claw dermal cells of dairy cow and clarify the potential mechanisms. In the current research, the primary claw dermal cells were exposed to gradient concentrations of AP (10, 50, 100 µg/mL) in the presence of 10 µg/mL LPS. The levels of cytokines and nitric oxide (NO) were detected with ELISA and Griess colorimetric method. The mRNA expressions of TLR4, MyD88 and chemokines were measured with qPCR. The activation of NF-κB and MAPK signaling pathways was detected with western blotting.

Results

The results indicated that AP reduced the production of inflammatory mediators (TNF-α, IL-1β, IL-6 and NO), downregulated the mRNA expression of TLR4, MyD88 and some pro-inflammatory chemokines (CCL2, CCL20, CXCL2, CXCL8, CXCL10), and suppressed the NF-κB and MAPK signaling pathways evidenced by inhibition of the phosphorylation of IκBα, p65 and ERK, JNK, p38.

Conclusions

Our results demonstrated that AP may exert its anti-inflammatory effects on claw dermal cells of dairy cow by regulating the NF-κB and MAPK signaling pathways.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-02952-4.

Anti-atherosclerotic Effects of Spice-Derived Phytochemicals

Cardiovascular diseases are the leading cause of death in the world. Atherosclerosis is characterized by oxidized lipid deposition and inflammation in the arterial wall and represents a significant problem in public health and medicine. Some dietary spices have been widely used in many countries; however, the mechanism of their action as it relates to the prevention and treatment of atherosclerosis is still poorly understood. In this review, we focus on the properties of various spice-derived active ingredients used in the prevention and treatment of atherosclerosis, as well as associated atherosclerotic risk factors. We provide a summary of the mechanisms of action, epidemiological analyses, and studies of various components of spice used in the clinic, animal models, and cell lines related to atherosclerosis. Most notably, we focused on mechanisms of action by which these spice-derived compounds elicit their lipid-lowering, anti-inflammatory, antioxidant, and immunomodulatory properties, as well as their involvement in selected biochemical and signal transduction pathways. It is suggested that future research should aim to design well-controlled clinical trials and more thoroughly investigate the role of spices and their active components in the prevention/treatment of atherosclerosis. Based on this literature review, it appears that spices and their active components are well tolerated and have few adverse side effects and, therefore, provide a promising adjunctive treatment strategy for patients with atherosclerosis.

The roles of liver X receptor α in inflammation and inflammation-associated diseases

Liver X receptor α (LXRα; also known as NR1H3), an isoform of LXRs, is a member of the nuclear receptor family of transcription factors and plays essential roles in the transcriptional control of cholesterol homeostasis. Previous in-depth phenotypic analyses of mouse models with deficient LXRα have also demonstrated various physiological functions of this receptor within inflammatory responses. LXRα activation exerts a combination of metabolic and anti-inflammatory actions resulting in the modulation and the amelioration of inflammatory disorders. The tight "repercussions" between LXRα and inflammation, as well as cholesterol homeostasis, have suggested that LXRα could be pharmacologically targeted in pathologies such as atherosclerosis, acute lung injury, and Alzheimer's disease. This review gives an overview of the recent advances in understanding the roles of LXRα in inflammation and inflammation-associated diseases, which will help in the design of future experimental researches on the potential of LXRα and advance the investigation of LXRα as pharmacological inflammatory targets.

Protective Effects of Dietary Capsaicin on the Initiation Step of a Two-Stage Hepatocarcinogenesis Rat Model

Capsaicin (CPS), an ingredient of Capsicum plants, has anti-inflammatory, antioxidant and antitumoral properties. The mechanisms of CPS on hepatocarcinogenesis preclinical bioassays are not described. Thus, the protective effects CPS were evaluated in the early stages of chemically-induced hepatocarcinogenesis. Male Wistar rats received diet containing 0.01% or 0.02% CPS for 3 weeks. Afterwards, animals received a dose of hepatocarcinogen diethylnitrosamine (DEN, 100 mg/kg body weight). From weeks 4-12, groups had their diet replaced by a 0.05% phenobarbital supplemented one to promote DEN-induced preneoplastic lesions. Animals were euthanized 24 h after DEN administration (n = 5/group) or at week 12 (n = 9/group). The estimated CPS intake in rats resembled human consumption. At the end of week 3, dietary 0.02% CPS attenuated DEN-induced oxidative damage and, consequently, hepatocyte necrosis by reducing serum alanine aminotransferase levels, liver CD68-positive macrophages, lipid peroxidation, while increasing antioxidant glutathione system. Additionally, 0.02% CPS upregulated vanilloid Trpv1 receptor and anti-inflammatory epoxygenase Cyp2j4 genes in the liver. Ultimately, previous 0.02% CPS intake decreased the number of GST-P-positive preneoplastic lesions at week 12. Thus, CPS attenuated preneoplastic lesion development, primarily by diminishing DEN-induced oxidative liver injury. Findings indicate that CPS is a promising chemopreventive agent when administered after and during the early stages of hepatocarcinogenesis.

Dihydrocapsaicin-induced angiogenesis and improved functional recovery after cerebral ischemia and reperfusion in a rat model

This study investigated the long-term effects of dihydrocapsaicin (DHC)-induced angiogenesis and improved functional outcomes in cerebral ischemia and reperfusion (I/R) rats. Middle cerebral artery occlusion was induced in I/R rats for 2 h, followed by reperfusion. The animals were divided into three groups: sham, I/R + vehicle, and I/R + DHC (10 mg/kg body weight). Fourteen days after I/R injury, the DHC-treated I/R rats had decreased neurological deficit scores, infarct volume, and brain morphology changes. DHC-induced angiogenesis significantly increased the expression of angiogenic factor proteins, such as hypoxia inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF), and matrix metalloprotease 9 (MMP-9), at 3 d and 14 d following I/R and also increased the expression of angiogenic inhibitors, such as angiopoietin 1 (Ang-1) and its receptor tyrosine kinase (Tie-2), at 14 d following reperfusion. DHC-mediated angiogenesis was confirmed by a significant increase in positive BrdU labeling that co-localized with the von Willebrand factor (an endothelial cell marker) at 14 d after I/R. Furthermore, rotarod and pole tests demonstrated that DHC promoted functional recovery when compared with the vehicle group. Thus, the results reveal that DHC mediates angiogenesis and functional recovery after an ischemic stroke.

The protective effects of saxagliptin against lipopolysaccharide (LPS)-induced inflammation and damage in human dental pulp cells

Bacteria play a pivotal role in the pathological initiation and progression of pulpitis. Lipopolysaccharide (LPS) is recognized as a major component of the outer wall of Gram-negative bacteria. Saxagliptin, a potent inhibitor of dipeptidyl peptidase-4 (DPP-4), has been licensed for the treatment of type 2 diabetes. In this study, we aimed to evaluate the protective effects of saxagliptin against LPS-induced intracellular insults in human dental pulp cells (HDPCs). We found that DPP-4 is expressed in HDPCs. Interestingly, the expression of DPP-4 was increased in response to LPS treatment. We also found that saxagliptin ameliorated LPS-induced production of ROS and reduction of glutathione (GSH). Additionally, saxagliptin prevented LPS-induced mitochondrial dysfunction by increasing the levels of mitochondrial membrane potential (MMP) and the production of adenosine triphosphate (ATP). Importantly, saxagliptin ameliorated LPS-induced reduction of cell viability and lactate dehydrogenase (LDH) release. Our results indicate that saxagliptin significantly inhibited LPS-induced expression and secretions of tumour necrosis factor alpha (TNF-α), interleukin (IL)-1β and IL-6 in HDPCs. Mechanistically, we found that saxagliptin inhibited the phosphorylation of p38 and the activation of NF-κB. Our findings suggest that saxagliptin might have a potential therapeutic capacity for the treatment of pulpitis through mitigating inflammatory signalling in dental pulp cells.

Epimagnolin A inhibits IL-6 production by inhibiting p38/NF-κB and AP-1 signaling pathways in PMA-stimulated THP-1 cells

Epimagnolin A is a lignan obtained from the flower buds of Magnolia fargesii, which is traditionally used in Asian medicine for treating headache and nasal congestion. A herbal compound fargesin obtained from M. fargesii, has exerted anti-inflammatory effects in human monocytic THP-1 cells in the previous study. The anti-inflammatory effects of epimagnolin A, however, have been not elucidated yet. In this study, it was demonstrated that epimagnolin A reduced phorbol-12-myristate-13-acetate (PMA)-induced IL-6 promoter activity and IL-6 production in human monocytic THP-1 cells. Furthermore, it was investigated the modulating effects of epimagnolin A on mitogen-activated protein kinase, nuclear factor-kappa B (NF-κB), and activator protein 1 (AP-1) activities. Phosphorylation of p38 and nuclear translocation of p50 and c-Jun were down-regulated by epimagnolin A in the PMA-stimulated THP-1 cell. The results revealed that epimagnolin A attenuated the binding affinity of NF-κB and AP-1 transcription factors to IL-6 promoter and IL-6 production through p38/NF-kB and AP-1 signaling pathways in the PMA-stimulated THP-1 cells. These results suggest that epimagnolin A can be a useful drug for the treatment of inflammatory diseases.

Capsaicin Analogues Derived from n-3 Polyunsaturated Fatty Acids (PUFAs) Reduce Inflammatory Activity of Macrophages and Stimulate Insulin Secretion by β-Cells In Vitro

In this study, two capsaicin analogues, N-eicosapentaenoyl vanillylamine (EPVA) and N-docosahexaenoyl vanillylamine (DHVA), were enzymatically synthesized from their corresponding n-3 long chain polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), both dietary relevant components. The compounds significantly reduced the production of some lipopolysaccharide (LPS)-induced inflammatory mediators, including nitric oxide (NO), macrophage-inflammatory protein-3α (CCL20) and monocyte chemoattractant protein-1 (MCP-1 or CCL2), by RAW264.7 macrophages. Next to this, only EPVA increased insulin secretion by pancreatic INS-1 832/13 β-cells, while raising intracellular Ca2+ and ATP concentrations. This suggests that the stimulation of insulin release occurs through an increase in the intracellular ATP/ADP ratio in the first phase, while is calcium-mediated in the second phase. Although it is not yet known whether EPVA is endogenously produced, its potential therapeutic value for diabetes treatment merits further investigation.

Development of A New Delivery System Based on Drug-Loadable Electrospun Nanofibers for Psoriasis Treatment

Psoriasis is a chronic autoimmune systemic disease with an approximate incidence of 2% worldwide; it is commonly characterized by squamous lesions on the skin that present the typical pain, stinging, and bleeding associated with an inflammatory response. In this work, poly(methyl vinyl ether-alt-maleic ethyl monoester) (PMVEMA-ES) nanofibers have been designed as a delivery vehicle for three therapeutic agents with palliative properties for the symptoms of this disease (salicylic acid, methyl salicylate, and capsaicin). For such a task, the production of these nanofibers by means of the electrospinning technique has been optimized. Their morphology and size have been characterized by optical microscopy and scanning electron microscopy (SEM). By selecting the optimal conditions to achieve the smallest and most uniform nanofibers, approximate diameters of up to 800⁻900 nm were obtained. It was also determined that the therapeutic agents that were used were encapsulated with high efficiency. The analysis of their stability over time by GC-MS showed no significant losses of the encapsulated compounds 15 days after their preparation, except in the case of methyl salicylate. Likewise, it was demonstrated that the therapeutic compounds that were encapsulated conserved, and even improved, their capacity to activate the transient receptor potential cation channel 1 (TRPV1) channel, which has been associated with the formation of psoriatic lesions.

TRPV1 mediates capsaicin-stimulated metabolic activity but not cell death or inhibition of interleukin-1β release in human THP-1 monocytes

Human monocytes and dendritic cells express transient receptor potential vanilloid 1 (TRPV1) which may play a role in mediating the inflammatory, immune and cancer surveillance responses of these cells. The aim of the present study was to investigate TRPV1 expression and function in THP-1 monocytic cells. RT-PCR and Western blot were used to detect TRPV1. The metabolic activity and viability of THP-1 cells following exposure to vanilloids was assessed using resorufin production from rezazurin. Cytokine release was measured using ELISA. TRPV1 was expressed in cultured THP-1 monocytic cells and naïve monocytes. Lower concentrations (<250 μM) of capsaicin, but not other putative TRPV1 agonists, were shown to stimulate cell metabolic activity, whereas at concentrations >250 μM, all agonists decreased metabolic activity. Capsaicin-stimulated THP-1 metabolic activity was blocked by the TRPV1 antagonist, 5-iodo-resiniferatoxin (5'-IRTX), whereas the decline in resorufin production by THP-1 cells at higher capsaicin concentrations (due to cell death), was not affected by 5'-IRTX. Finally, capsaicin (≤125 μM) significantly increased lipopolysaccharide-stimulated IL-6 and TNF-α release from THP-1 cells, whereas phytohaemagglutinin-stimulated IL-1β, TNF-α, MCP-1 and IL-6 release were concentration-dependently inhibited by capsaicin. Modulation of IL-1β release was not TRPV1 mediated. Overall, these results show that functional TRPV1 channels are present in naïve monocytes and THP-1 cells, and when activated, increase cell metabolic activity. In addition, capsaicin modifies cytokine release from THP-1 cells and induces cell death, most likely by a mechanism that is independent of TRPV1 activation.

Anti-inflammatory and Mineralization Effects of ProRoot MTA and Endocem MTA in Studies of Human and Rat Dental Pulps In Vitro and In Vivo

INTRODUCTION

Few studies have reported direct pulp capping in inflamed pulp conditions. The purpose of this study was to investigate the in vitro and in vivo responses of dental pulp during direct pulp capping using various pulp capping materials in inflamed conditions.

METHODS

Human dental pulp cells were treated with lipopolysaccharide (LPS) and cultured with Dycal (Dentsply Caulk, Milford, DE), ProRoot MTA (Dentsply Maillefer, Ballaigues, Switzerland), and Endocem MTA (Maruchi, Wonju, South Korea). The expressions of interleukin (IL)-1β, IL-6, dentin matrix protein 1, and dentin sialophosphoprotein were analyzed through real-time polymerase chain reaction. The maxillary molars of Sprague-Dawley rats were exposed for 2 days. The exposed pulps were capped with Dycal, ProRoot MTA, and Endocem MTA and sealed with resin-modified glass ionomer followed by histologic and immunohistochemical analyses.

RESULTS

The expression of IL-1β and IL-6 was increased with LPS and decreased by Dycal, ProRoot MTA, and Endocem MTA. Dentin matrix protein 1 and dentin sialophosphoprotein levels were decreased with LPS and increased after treatment with pulp capping materials.In the in vivo study, inflammation associated with Dycal was higher than that associated with ProRoot MTA and Endocem MTA at week 1, without any significant difference between the 2. At 4 weeks, inflammation was decreased, and mineralization was increased compared with week 1 in all 3 of the materials. At week 1, IL-6 immunoreactivity was strongly expressed. Dycal exhibited stronger immunoreactivity than ProRoot MTA and Endocem MTA. However, the immunoreactivity was decreased in all groups at week 4.

CONCLUSIONS

Successful direct pulp capping requires more effective pulp capping materials for the treatment of inflamed pulps.

Capsaicinoids improve consequences of physical activity

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Capsaicinoids (CAPs) are active compounds in Capsicum fruits.

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CAPs have anti-inflammatory and antioxidant properties.

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CAPs with regular exercise may enhance lipid metabolism.

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CAPs down-regulate muscle SREBP-1c, LXRs, ACLY, FAS in exercised rats.

The purpose of this study was to investigate the effects of capsaicinoids (CAPs) on lipid metabolism, inflammation, antioxidant status and the changes in gene products involved in these metabolic functions in exercised rats. A total of 28 male Wistar albino rats were randomly divided into four groups (n = 7) (i) No exercise and no CAPs, (ii) No exercise + CAPs (iii) Regular exercise, (iv) Regular exercise + CAPs. Rats were administered as 0.2 mg capsaicinoids from 10 mg/kg BW/day Capsimax^® daily for 8 weeks. A significant decrease in lactate and malondialdehyde (MDA) levels and increase in activities of antioxidant enzymes were observed in the combination of regular exercise and CAPs group (P < 0.0001). Regular exercise + CAPs treated rats had greater nuclear factor-E2-related factor-2 (Nrf2) and heme oxygenase-1 (HO-1) levels in muscle than regular exercise and no exercise rats (P < 0.001). Nevertheless, regular exercise + CAPs treated had lower nuclear factor kappa B (NF-κB) and IL-10 levels in muscle than regular exercise and control rats (P < 0.001). Muscle sterol regulatory element-binding protein 1c (SREBP-1c), liver X receptors (LXR), ATP citrate lyase (ACLY) and fatty acid synthase (FAS) levels in the regular exercise + CAPs group were lower than all groups (P < 0.05). However, muscle PPAR-γ level was higher in the regular exercise and CAPs alone than the no exercise rats. These results suggest CAPs with regular exercise may enhance lipid metabolism by regulation of gene products involved in lipid and antioxidant metabolism including SREBP-1c, PPAR-γ, and Nrf2 pathways in rats.

Chronic diseases, inflammation, and spices: how are they linked?

Extensive research within the last several decades has revealed that the major risk factors for most chronic diseases are infections, obesity, alcohol, tobacco, radiation, environmental pollutants, and diet. It is now well established that these factors induce chronic diseases through induction of inflammation. However, inflammation could be either acute or chronic. Acute inflammation persists for a short duration and is the host defense against infections and allergens, whereas the chronic inflammation persists for a long time and leads to many chronic diseases including cancer, cardiovascular diseases, neurodegenerative diseases, respiratory diseases, etc. Numerous lines of evidence suggest that the aforementioned risk factors induced cancer through chronic inflammation. First, transcription factors NF-κB and STAT3 that regulate expression of inflammatory gene products, have been found to be constitutively active in most cancers; second, chronic inflammation such as pancreatitis, prostatitis, hepatitis etc. leads to cancers; third, activation of NF-κB and STAT3 leads to cancer cell proliferation, survival, invasion, angiogenesis and metastasis; fourth, activation of NF-κB and STAT3 leads to resistance to chemotherapy and radiation, and hypoxia and acidic conditions activate these transcription factors. Therefore, targeting these pathways may provide opportunities for both prevention and treatment of cancer and other chronic diseases. We will discuss in this review the potential of various dietary agents such as spices and its components in the suppression of inflammatory pathways and their roles in the prevention and therapy of cancer and other chronic diseases. In fact, epidemiological studies do indicate that cancer incidence in countries such as India where spices are consumed daily is much lower (94/100,000) than those where spices are not consumed such as United States (318/100,000), suggesting the potential role of spices in cancer prevention.

Impact of capsaicin, an active component of chili pepper, on pathogenic chlamydial growth (Chlamydia trachomatis and Chlamydia pneumoniae) in immortal human epithelial HeLa cells

Chlamydia trachomatis is the leading cause of sexually transmitted infections worldwide. Capsaicin, a component of chili pepper, which can stimulate actin remodeling via capsaicin receptor TRPV1 (transient receptor potential vanilloid 1) and anti-inflammatory effects via PPARγ (peroxisome proliferator-activated receptor-γ) and LXRα (liver X receptor α), is a potential candidate to control chlamydial growth in host cells. We examined whether capsaicin could inhibit C. trachomatis growth in immortal human epithelial HeLa cells. Inclusion forming unit and quantitative PCR assays showed that capsaicin significantly inhibited bacterial growth in cells in a dose-dependent manner, even in the presence of cycloheximide, a eukaryotic protein synthesis inhibitor. Confocal microscopic and transmission electron microscopic observations revealed an obvious decrease in bacterial numbers to inclusions bodies formed in the cells. Although capsaicin can stimulate the apoptosis of cells, no increase in cleaved PARP (poly (ADP-ribose) polymerase), an apoptotic indicator, was observed at a working concentration. All of the drugs tested (capsazepine, a TRPV1 antagonist; 5CPPSS-50, an LXRα inhibitor; and T0070907, a PPARγ inhibitor) had no effect on chlamydial inhibition in the presence of capsaicin. In addition, we also confirmed that capsaicin inhibited Chlamydia pneumoniae growth, indicating a phenomena not specific to C. trachomatis. Thus, we conclude that capsaicin can block chlamydial growth without the requirement of host cell protein synthesis, but by another, yet to be defined, mechanism.

Anti-inflammatory effects of water extract from bell pepper (Capsicum annuum L. var. grossum) leaves in vitro

Fruits and vegetables have been recognized as natural sources of various bioactive compounds. Peppers, one such natural source, are consumed worldwide as spice crops. They additionally have an important role in traditional medicine, as a result of their antioxidant bioactivity via radical scavenging. However, there are no reports regarding the bioactivity of the bell pepper (Capsicum annuum L. var. grossum), a commonly used edible vegetable. The present study aimed to evaluate the anti-inflammatory effect of water extract from bell pepper leaves on mouse spleen cells, and explore the potential mechanism underlying this effect. The extract was prepared through homogenization of bell pepper leaves in deionized water. The sterilized supernatant was added to a mouse spleen cell culture stimulated by concanavalin A. Following 72 h of culture, the levels of inflammatory cytokines in the culture supernatant were measured using a sandwich enzyme-linked immunosorbent assay system, and levels of inflammatory proteins were assessed using western blotting. The bell pepper leaf extract significantly inhibited inflammatory cytokine production, inhibited cell proliferation without producing cytotoxicity, and suppressed the expression of inflammatory proteins. These results suggest that components of the bell pepper leaf extract possess anti-inflammatory activity. The study of the anti-inflammatory mechanism of bell pepper leaf extract has provided useful information on its potential for therapeutic application.

Dihydrocapsaicin Attenuates Blood Brain Barrier and Cerebral Damage in Focal Cerebral Ischemia/Reperfusion via Oxidative Stress and Inflammatory

This study investigated the effect of dihydrocapsaicin (DHC) on cerebral and blood brain barrier (BBB) damage in cerebral ischemia and reperfusion (I/R) models. The models were induced by middle cerebral artery occlusion (MCAO) for 2 h followed by reperfusion. The rats were divided into five groups: sham, or control group; vehicle group; and 2.5 mg/kg, 5 mg/kg, and 10 mg/kg BW DHC-treated I/R groups. After 24 h of reperfusion, we found that DHC significantly reduced the area of infarction, morphology changes in the neuronal cells including apoptotic cell death, and also decreased the BBB damage via reducing Evan Blue leakage, water content, and ultrastructure changes, in addition to increasing the tight junction (TJ) protein expression. DHC also activated nuclear-related factor-2 (Nrf2) which involves antioxidant enzymes like superoxide dismutase (SOD) and glutathione peroxidase (GPx), and significantly decreased oxidative stress and inflammation via down-regulated reactive oxygen species (ROS), NADPH oxidase (NOX2, NOX4), nuclear factor kappa-beta (NF-ĸB), and nitric oxide (NO), including matrix metalloproteinases-9 (MMP-9) levels. DHC protected the cerebral and the BBB from I/R injury via attenuation of oxidative stress and inflammation. Therefore, this study offers to aid future development for protection against cerebral I/R injury in humans.

Health-promoting properties of compounds derived from Capsicum sp. A review

This article presents multidirectional effects of capsaicin and its natural derivatives as well as natural and synthetic analogs in term of their therapeutic properties. Active agents present in various Capsicum genus plants exert analgesic, anti-inflammatory, antibacterial, antioxidant and gastroprotective effects. Furthermore, capsaicin positively influences the metabolism of lipids. Numerous research show that capsaicinoids inhibit proliferation and migration process of cancer cells, what makes them molecules of high interest in oncology. Among broad range of positive activities, we have focused only on those properties that have already found application in medicine or seemed to be the most probably used in the near future. Even if in low or single doses this compound has been reported successful in numerous therapies, the negative consequences of high doses or prolonged administration is also discussed in the review.

Activation of liver X receptors promotes inflammatory cytokine mRNA degradation by upregulation of tristetraprolin

Liver X receptors (LXRs) have anti-inflammatory properties. Whether LXRs play a role in post-transcriptional control of inflammatory cytokine expression is not clear. Here, we firstly identified that the synthetic LXR agonist T0901317 promoted IL-1β, IL-6 and TNFα mRNA degradation. Moreover, T0901317 destabilized TNFα mRNA through its 3'-untranslated region. In addition, T0901317 increased the expression of tristetraprolin (TTP), while antagonizing TTP with siRNA abrogated T0901317-mediated inflammatory cytokine mRNA decay. Interestingly, T0901317 repressed LPS-induced phosphorylation of ERK1/2 and p38 mitogen-activated protein kinase (MAPK) in THP-1 macrophages. The evidence presented here confirms that LXR activation with T0901317 inhibits the phosphorylation of ERK1/2 and p38 MAPK, likely resulting in the increased expression of TTP and the decay of LPS-induce inflammatory cytokine mRNAs.

An updated review on molecular mechanisms underlying the anticancer effects of capsaicin

The quest for developing anticancer principles from natural sources has a long historical track record and remarkable success stories. The pungent principle of hot chili pepper, capsaicin, has been a subject of research for anticancer drug discovery for more than three decades. However, the majority of research has revealed that capsaicin interferes with various hallmarks of cancer, such as increased cell proliferation, evasion from apoptosis, inflammation, tumor angiogenesis and metastasis, and tumor immune escape. Moreover, the compound has been reported to inhibit carcinogen activation and chemically induced experimental tumor growth. Capsaicin has also been reported to inhibit the activation of various kinases and transcription that are involved in tumor promotion and progression. The compound activated mitochondria-dependent and death receptor-mediated tumor cell apoptosis. Considering the growing interest in capsaicin, this review provides an update on the molecular targets of capsaicin in modulating oncogenic signaling.

Capsaicin Inhibits Dimethylnitrosamine-Induced Hepatic Fibrosis by Inhibiting the TGF-β1/Smad Pathway via Peroxisome Proliferator-Activated Receptor Gamma Activation

Capsaicin (CPS) exerts many pharmacological effects, but any possible influence on liver fibrosis remains unclear. Therefore, we evaluated the inhibitory effects of CPS on dimethylnitrosamine (DMN) and TGF-β1-induced liver fibrosis in rats and hepatic stellate cells (HSCs). CPS inhibited DMN-induced hepatotoxicity, NF-κB activation, and collagen accumulation. CPS also suppressed the DMN-induced increases in α-SMA, collagen type I, MMP-2, and TNF-α. In addition, CPS inhibited DMN-induced TGF-β1 expression (from 2.3 ± 0.1 to 1.0 ± 0.1) and Smad2/3 phosphorylation (from 1.5 ± 0.1 to 1.1 ± 0.1 and from 1.6 ± 0.1 to 1.1 ± 0.1, respectively) by activating Smad7 expression (from 0.1 ± 0.0 to 0.9 ± 0.1) via PPAR-γ induction (from 0.2 ± 0.0 to 0.8 ± 0.0) (p < 0.05). Furthermore, in HSCs, CPS inhibited the TGF-β1-induced increases in α-SMA and collagen type I expression, via PPAR-γ activation. These results indicate that CPS can ameliorate hepatic fibrosis by inhibiting the TGF-β1/Smad pathway via PPAR-γ activation.