Anti-inflammatory and analgesic effects of the sesquiterpene lactone budlein A in mice: inhibition of cytokine production-dependent mechanism

Anti-inflammatory potential of some eudesmanolide and guaianolide sesquiterpenes

Ten sesquiterpene lactones isolated from Anvillea garcinii (Burm.f.) DC ethanolic extract were assessed for their anti-inflammatory potential by myeloperoxidase (MPO) activity assignment, and mice paw swelling model. 3α,4α-10β-trihydroxy-8α-acetyloxyguaian-12,6α-olide (1), epi-vulgarin (3), 9a-hydroxyparthenolide (4), garcinamine C (7), garcinamine D (8), garcinamine E (9), and 4, 9-dihydroxyguaian-10(14)-en-12-olide (10) showed explicit anti-inflammatory activity in rodent paw edema and MPO assignment. The findings of this study showed that the α-methylene γ-lactone moiety does not always guarantee an anti-inflammatory effect, but the presence of proline at the C3 of the lactone ring improves the binding of sesquiterpene lactones with MPO isoenzymes, resulting in a more potent inhibition.

Lafoensia pacari alleviates intestinal damage by modulating cyclooxygenase-2: In silico and in vivo evaluation in a colitis model

BACKGROUND

Inflammatory bowel diseases (IBD) are a worldwide health problem and mainly affect young people, consequently affecting the workforce. Available treatments are often associated with side effects, and new therapeutic options are needed. For centuries, plants have represented important substrates in the field of drug development. Lafoensia pacari (L. pacari) is a plant whose pharmaceutical potential has been described, and may have biological activity relevant to the treatment of IBD symptoms.

AIM

To investigate the activity of keto-alcoholic extracts of L. pacari with respect to ameliorating the inflammatory and nociceptive symptoms of acute experimental colitis in mice.

METHODS

Keto-alcoholic extracts of L. pacari leaves and bark were administered to male and female Swiss mice weighing 25 g to 30 g (n = 8 male mice and n = 8 female mice). The effect of these extracts was observed in an acetic acid-induced acute experimental model of colitis with regard to antinociception/analgesia and inflammatory tissue damage. Recorded macroscopic indices included the Wallace score and the colon weight obtained using a precision scale. Mechanical hyperalgesia was determined using an electronic analgesimeter. Behavior related to overt pain was determined by quantifying the number of writhing instances within 20 min of administration of acetic acid. Molecular docking was performed using human and murine cyclooxygenase-2 (COX-2) with 3 flavonoids (ellagic acid, kaempferol, and quercetin) on the AutoDock Vina software. Analysis of variance followed by Tukey’s posttest was used with P < 0.05 indicating significance.

RESULTS

In this murine model of colitis, administration of extracts from L. pacari ameliorated acetic acid-induced writhing and colitis-associated inflammatory pain. These improvements may be attributable to the reduction in edema, inflammation (e.g., ulcers, hyperemia, and bowel wall damage), and the intensity of abdominal hyperalgesia. The keto-alcoholic extracts of L. pacari leaves and bark administered at a dose of either 100 mg/kg or 300 mg/kg significantly reduced the number of writhing events when compared to the negative control (P < 0.05). Additionally, extracts of L. pacari bark also performed better than Dipyrone. Leaf extracts administered at 10 mg/kg, 30 mg/kg, and 100 mg/kg and bark extracts administered at 30 mg/kg significantly reduced or prevented the development of edema in the colon of treated mice, while mesalazine did not. Moreover, using molecular docking, we observed that the flavonoids present in L. pacari extracts bind to COX-2, an event not unique to ellagic acid.

CONCLUSION

The results of this study demonstrate a potential novel application of L. pacari extracts for the reduction of inflammation and promotion of antinociception/analgesia as demonstrated by our findings in a murine model of colitis. These findings were also corroborated by in silico analyses, and suggest that L. pacari extracts may be a promising therapeutic agent in the treatment of IBD.

Hesperidin Methyl Chalcone Reduces the Arthritis Caused by TiO2 in Mice: Targeting Inflammation, Oxidative Stress, Cytokine Production, and Nociceptor Sensory Neuron Activation

Arthroplasty is an orthopedic surgical procedure that replaces a dysfunctional joint by an orthopedic prosthesis, thereby restoring joint function. Upon the use of the joint prosthesis, a wearing process begins, which releases components such as titanium dioxide (TiO₂) that trigger an immune response in the periprosthetic tissue, leading to arthritis, arthroplasty failure, and the need for revision. Flavonoids belong to a class of natural polyphenolic compounds that possess antioxidant and anti-inflammatory activities. Hesperidin methyl chalcone's (HMC) analgesic, anti-inflammatory, and antioxidant effects have been investigated in some models, but its activity against the arthritis caused by prosthesis-wearing molecules, such as TiO₂, has not been investigated. Mice were treated with HMC (100 mg/kg, intraperitoneally (i.p.)) 24 h after intra-articular injection of 3 mg/joint of TiO₂, which was used to induce chronic arthritis. HMC inhibited mechanical hyperalgesia, thermal hyperalgesia, joint edema, leukocyte recruitment, and oxidative stress in the knee joint (alterations in gp91^phox, GSH, superoxide anion, and lipid peroxidation) and in recruited leukocytes (total reactive oxygen species and GSH); reduced patellar proteoglycan degradation; and decreased pro-inflammatory cytokine production. HMC also reduced the activation of nociceptor-sensory TRPV1⁺ and TRPA1⁺ neurons. These effects occurred without renal, hepatic, or gastric damage. Thus, HMC reduces arthritis triggered by TiO₂, a component released upon wearing of prosthesis.

Ehrlich Tumor Induces TRPV1-Dependent Evoked and Non-Evoked Pain-like Behavior in Mice

We standardized a model by injecting Ehrlich tumor cells into the paw to evaluate cancer pain mechanisms and pharmacological treatments. Opioid treatment, but not cyclooxygenase inhibitor or tricyclic antidepressant treatments reduces Ehrlich tumor pain. To best use this model for drug screening it is essential to understand its pathophysiological mechanisms. Herein, we investigated the contribution of the transient receptor potential cation channel subfamily V member 1 (TRPV1) in the Ehrlich tumor-induced pain model. Dorsal root ganglia (DRG) neurons from the Ehrlich tumor mice presented higher activity (calcium levels using fluo-4 fluorescent probe) and an increased response to capsaicin (TRPV1 agonist) than the saline-injected animals (p < 0.05). We also observed diminished mechanical (electronic von Frey) and thermal (hot plate) hyperalgesia, paw flinching, and normalization of weight distribution imbalance in TRPV1 deficient mice (p < 0.05). On the other hand, TRPV1 deficiency did not alter paw volume or weight, indicating no significant alteration in tumor growth. Intrathecal injection of AMG9810 (TRPV1 antagonist) reduced ongoing Ehrlich tumor-triggered mechanical and thermal hyperalgesia (p < 0.05). Therefore, the contribution of TRPV1 to Ehrlich tumor pain behavior was revealed by genetic and pharmacological approaches, thus, supporting the use of this model to investigate TRPV1-targeting therapies for the treatment of cancer pain.

Oral administration of botryosphaeran [(1 → 3)(1 → 6)-β-d-glucan] reduces inflammation through modulation of leukocytes and has limited effect on inflammatory nociception

Several biological activities of the fungal exopolysaccharide (1 → 3)(1 → 6)-β-d-glucan (botryosphaeran) have been described in the literature, but its effects on inflammation have not been evaluated. This study aimed to investigate the action of botryosphaeran on experimental mice models of carrageenan-induced acute pleurisy and acute paw edema, and complete Freund's adjuvant-induced persistent paw edema. All botryosphaeran doses tested (1.0, 2.5, 5.0, and 10.0 mg/kg birth weight [b.w.], orally administered) reduced leukocyte recruitment, nitric oxide (NO) levels, and protein extravasation in the pleural cavity. Botryosphaeran (5 mg/kg b.w.) did not diminish edema and mechanical hyperalgesia in the paw within 4 h; however, cold allodynia was alleviated within the first 2 h. In the persistent paw inflammation model, the effects of daily oral administration of botryosphaeran (5 mg/kg b.w.) were evaluated over 3 and 7 days. The fungal β-glucan significantly reduced the levels of the cytokines, tumor necrosis factor(TNF)-α, interleukin (IL)-6), and IL-10, in the paw homogenates in both protocols, while paw edema and the levels of advanced oxidation protein products (AOPP) only diminished on Day 7. No effect in mechanical hyperalgesia was observed. Oral treatment for 3 or 7 days also decreased the plasma levels of NO, AOPP, TNF-α, and IL-10. On Day 7, the number of leukocytes in the blood was also reduced by this treatment. Importantly, botryosphaeran did not induce inflammation in mice when administered alone over 7 days. This study demonstrated the anti-inflammatory and antinociceptive potential of botryosphaeran in these experimental models, making this fungal β-glucan a new possibility for complementary treating acute and chronic inflammation.

The sesquiterpene lactone estafiatin exerts anti-inflammatory effects on macrophages and protects mice from sepsis induced by LPS and cecal ligation puncture

BACKGROUND

Previously, we found that the water extract of Artermisia scoparia Waldst. & Kit suppressed the cytokine production of lipopolysaccharide (LPS)-stimulated macrophages and alleviated carrageenan-induced acute inflammation in mice. Artemisia contains various sesquiterpene lactones and most of them exert immunomodulatory activity.

PURPOSE

In the present study, we investigated the immunomodulatory effect of estafiatin (EST), a sesquiterpene lactone derived from A. scoparia, on LPS-induced inflammation in macrophages and mouse sepsis model.

STUDY DESIGN AND METHODS

Murine bone marrow-derived macrophages (BMDMs) and THP-1 cells, a human monocytic leukemia cell line, were pretreated with different doses of EST for 2 h, followed by LPS treatment. The gene and protein expression of pro-inflammatory cytokines interleukin (IL)-6, tumor necrosis factor (TNF)-α, and inducible nitric oxide synthase (iNOS) were measured by quantitative real-time polymerase chain reaction (qPCR) and Western blot analysis. The activation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) was also evaluated at the level of phosphorylation. The effect of EST on inflammatory cytokine production, lung histopathology, and survival rate was assessed in an LPS-induced mice model of septic shock. The effect of EST on the production of cytokines in LPS-stimulated peritoneal macrophages was evaluated by in vitro and ex vivo experiments and protective effect of EST on cecal ligation and puncture (CLP) mice was also assessed.

RESULTS

The LPS-induced expression of IL-6, TNF-α, and iNOS was suppressed at the mRNA and protein levels in BMDMs and THP-1 cells, respectively, by pretreatment with EST. The half-maximal inhibitory concentration (IC50) of EST on IL-6 and TNF-α production were determined as 3.2 μM and 3.1 μM in BMDMs, 3 μM and 3.4 μM in THP1 cells, respectively. In addition, pretreatment with EST significantly reduced the LPS-induced phosphorylation p65, p38, JNK, and ERK in both cell types. In the LPS-induced mice model of septic shock, serum levels of IL-6, TNF-α, IL-1β, CXCL1, and CXCL2 were lower in EST-treated mice than in the control animals. Histopathology analysis revealed that EST treatment ameliorated LPS-induced lung damage. Moreover, while 1 of 7 control mice given lethal dose of LPS survived, 3 of 7 EST-treated (1.25 mg/kg) mice and 5 of 7 EST-treated (2.5 mg/kg) mice were survived. Pretreatment of EST dose-dependently suppressed the LPS-induced production of IL-6, TNF-α and CXCL1 in peritoneal macrophages. In CLP-induced mice sepsis model, while all 6 control mice was dead at 48 h, 1 of 6 EST-treated (1.25 mg/kg) mice and 3 of 6 EST-treated (2.5 mg/kg) mice survived for 96 h.

CONCLUSION

These results demonstrated that EST exerts anti-inflammatory effects on LPS-stimulated macrophages and protects mice from sepsis. Our study suggests that EST could be developed as a new therapeutic agent for sepsis and various inflammatory diseases.

Antinociceptive effects of a hydroethanolic stem bark extract of Burkea africana

Introduction

Pain is a major symptom of many clinical disorders and its relief has long been a concern for individuals across the globe. There is therefore an unmet need to search for new efficacious agents for the effective management of pain. The stem bark of the savanna tree Burkea africana (Hook) (Family: Leguminosae) is used in the Ghanaian traditional medicine for the treatment and management of various pain-related diseases.

Method

An acute oral toxicity study in mice was conducted by administering BAE (50–5000 mg kg⁻¹p.o.). Antinociceptive effect of BAE (50–1000 mg kg⁻¹p.o.) was evaluated using the acetic acid-induced abdominal constriction, acidic saline-induced muscle pain and formalin-induced pain models. The antinociceptive mechanism of BAE was also assessed using the formalin-induced pain model.

Results

The LD₅₀ of BAE was thus estimated to be above 5000 mg kg⁻¹ since none of the animals died in the acute toxicity study. Pretreatment with BAE (50–1000 mg kg⁻¹p.o.) significantly reduced the number of writhes after acetic-acid administration compared to the vehicle treated group. BAE also produced a significant and dose-dependent reversal of mechanical hyperalgesia induced by the injection of the acidic saline. Administration of BAE was able to significantly suppress both phases of the formalin test. This effect of the extract was however reversed by pretreatment with naloxone and granisetron.

Conclusions

BAE exhibits antinociceptive effects in rodent pain models with a possible involvement of 5-HT₃ receptors and opioidergic pathways.

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Burkea africana stem bark extract.

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Acetic acid-induced abdominal constriction.

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Acidic saline-induced muscle pain.

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Formalin-induced pain.

Sesquiterpene Lactones: Promising Natural Compounds to Fight Inflammation

Inflammation is a crucial and complex process that reestablishes the physiological state after a noxious stimulus. In pathological conditions the inflammatory state may persist, leading to chronic inflammation and causing tissue damage. Sesquiterpene lactones (SLs) are composed of a large and diverse group of highly bioactive plant secondary metabolites, characterized by a 15-carbon backbone structure. In recent years, the interest in SLs has risen due to their vast array of biological activities beneficial for human health. The anti-inflammatory potential of these compounds results from their ability to target and inhibit various key pro-inflammatory molecules enrolled in diverse inflammatory pathways, and prevent or reduce the inflammatory damage on tissues. Research on the anti-inflammatory mechanisms of SLs has thrived over the last years, and numerous compounds from diverse plants have been studied, using in silico, in vitro, and in vivo assays. Besides their anti-inflammatory potential, their cytotoxicity, structure–activity relationships, and pharmacokinetics have been investigated. This review aims to gather the most relevant results and insights concerning the anti-inflammatory potential of SL-rich extracts and pure SLs, focusing on their effects in different inflammatory pathways and on different molecular players.

Variation in essential oil components and anti-inflammatory activity of Allophylus edulis leaves collected in central-western Brazil

ETHNOPHARMACOLOGICAL RELEVANCE

An infusion obtained from the leaves of "chal-chal" (Allophylus edulis Radlk.) is used for popular treatment of intestinal disorders and as an anti-inflammatory throat treatment. Because of the anti-inflammatory medicinal folk use, a previous work reported scientific research confirming the anti-inflammatory activity of A. edulis essential oil collected in Dourados, MS, Brazil, in March 2015.

AIM OF THE STUDY

The aim of this study was to evaluate the variation in the chemical profile of the essential oil of A. edulis plants collected in Dourados (EOAE-D) and Bonito (EOAE-B), two cities in Mato Grosso do Sul State, Brazil. Additionally, we evaluated the anti-inflammatory effects of the essential oil, as well as that of the major compounds (caryophyllene oxide and α-zingiberene), in experimental in vivo models of inflammation in mice.

MATERIALS AND METHODS

Leaves were collected from plants at both sites in July 2018. The composition of the essential oil (EOAE-D and EOAE-B) was determined by GC/MS, and major compounds (caryophyllene oxide and α-zingiberene) were isolated and identified by chromatographic methods and NMR spectroscopy. Anti-inflammatory capacities were assessed using two classical models of inflammatory models, carrageenan- and CFA-induced paw inflammation (mechanical and thermal hyperalgesia).

RESULTS

Both EOAE-D and EOAE-B showed sesquiterpenes as a major constituent, namely, caryophyllene oxide (29.5%) and α-zingiberene (45.0%), respectively. In tests, EOAE, caryophyllene oxide and α-zingiberene-induced antiedematogenic and antihyperalgesic effects were found in the different utilized models.

CONCLUSIONS

The results indicate that samples from the two cities differed in chemical composition but not in their anti-inflammatory and antihyperalgesic effects. This finding corroborates the use of A. edulis as a medicinal plant and indicates its potential in the therapy of inflammatory conditions.

Cashew (Anacardium occidentale L.) Nuts Counteract Oxidative Stress and Inflammation in an Acute Experimental Model of Carrageenan-Induced Paw Edema

Background: Anacardium occidentale L. is a medicinal plant with powerful anti-oxidative and anti-inflammatory properties. Acute inflammatory events cause tissue alterations, decrease of anti-oxidative endogenous enzymes such as superoxide dismutase, catalase and glutathione, neutrophils infiltration, increase in the activities of myeloperoxidase, malondialdehyde, and pro-inflammatory release. Methods: Paw edema was induced by subplantar injection of carrageenan into the right hind paw in rats, but 30 min before a group of animals were orally treated with 100 mg/kg of cashew nuts to evaluate the anti-inflammatory and anti-oxidative response. Results: In the present work, we found that (1) cashew nuts reduced the development of carrageenan-induced paw edema limiting the formation of edema and pain; (2) cashew nuts ameliorated the diminutions of the anti-oxidative enzymes caused by carrageenan injection; (3) cashew nuts decreased myeloperoxidase malondialdehyde activity induced by carrageenan; and (4) cashew nuts acted by blocking pro-inflammatory cytokines response and nitrate/nitrite formation stimulated by carrageenan injection. Conclusions: The mechanisms of anti-inflammatory and analgesic effects exerted by cashew nuts were relevant to oxygen free radical scavenging, anti-lipid peroxidation, and inhibition of the formation of inflammatory cytokines.

Analgesic activity and mechanism of action of a Beta vulgaris dye enriched in betalains in inflammatory models in mice

Evidence demonstrates the pronounced anti-inflammatory activity of a beetroot (Beta vulgaris) dye enriched in betalains obtained using precipitation with ethanol. Herein, we expand upon our previous observations and demonstrate the analgesic and antioxidant effect of betalains. Betalains [10-1000 mg/kg; intraperitoneal route (i.p.)] diminished acetic acid- and PBQ-induced abdominal contortions, and the overt pain-like behaviour induced by complete Freund`s adjuvant (CFA) and formalin (intraplantar; i.pl.) injection. Moreover, betalains (100 mg/kg) administered by various routes [i.p. or subcutaneous (s.c.)] or as a post-treatment reduced carrageenin- or CFA-induced hyperalgesia. Mechanistically, betalains mitigated carrageenin-induced tumour necrosis factor-alpha (TNF-α), interleukin (IL)-1β, superoxide anion levels, and lipid peroxidation. Betalains also stopped the depletion of reduced glutathione (GSH) levels and ferric reducing ability produced by carrageenin, as well as upregulated Nrf2 and Ho1 transcript expression in the plantar tissue of mice. Furthermore, betalains showed hydroxyl radical, 2,2'-azino-di-(3-ethylbenzthiazoline-6-sulphonic acid) radical (ABTS⁺), and 2,2-diphenyl-1-picryl-hydrazyl radical (DPPH•) scavenging ability and iron-chelating activity (bathophenantroline assay), and inhibited iron-independent and iron-dependent lipid peroxidation (LPO) in vitro. Finally, betalains-treated bone marrow-derived macrophages exhibited lower levels of cytokines (TNF-α and IL-1β), and superoxide anion levels and nuclear factor kappa B (NF-κB) activation following lipopolysaccharide (LPS) stimulation. Therefore, this betalain-rich dye extracted using a novel precipitation approach presents prominent analgesic effect in varied models of pain by mechanisms targeting cytokines and oxidative stress.

Vernonia polysphaera Baker: Anti-inflammatory activity in vivo and inhibitory effect in LPS-stimulated RAW 264.7 cells

Species of the Vernonia genius are widely distributed across the world. In traditional communities, they are commonly used in popular medicine for the treatment of inflammatory diseases. The objective of the present study was to evaluate the anti-inflammatory activity of Vernonia polysphaera Baker hydroalcoholic extract. A λ-carrageenan-induced paw edema and peritonitis model was established in BALB/c mice. The in vitro activity of the extract was measured on LPS-stimulated RAW 264.7 cells. There was no toxic effect on mice or on the cells treated with the extract. Animals treated with V. polysphaera extract demonstrated inhibition of paw edema in comparison with the untreated animals at all the analyzed doses. In peritonitis, treatment with the extract at a dose of 500 mg/kg resulted in a lower total leukocyte count in the peritoneal fluid and blood and lower levels of IL-1β, IL-6, TNF-α and PGE-2 than the control group. Cells treated with 50 and 100 μg/mL of the extract exhibited lower levels of nitrite and pro-inflammatory cytokine production and lower COX-2, NF-κB expression. The V. polysphaera extract demonstrated an anti-inflammatory effect, interfering with cell migration, reducing pro-inflammatory cytokine levels and COX-2 expression and consequent interference with PGE-2, as well as inhibiting NF-κB transcription.

Involvement of the PKA pathway and inhibition of voltage gated Ca2+ channels in antihyperalgesic activity of Lippia grata/β-cyclodextrin

Neuropathic pain (NP) is a difficult condition to treat because of the modest efficacy of available drugs. New treatments are required. In the study we aimed to investigate the effects of the essential oil from Lippia grata alone or complexed in β-cyclodextrin (LG or LG-βCD) on persistent inflammatory and neuropathic pain in a mouse model. We also investigated Ca²⁺ currents in rat dorsal root ganglion (DRG) neurons. Male Swiss mice were treated with LG or LG/β-CD (24 mg/kg, i.g.) and their effect was evaluated using an acute inflammatory pleurisy model and nociception triggered by intraplantar injection of an agonist of the TRPs channels. We also tested their effect in chronic pain models: injection of Freund's Complete Adjuvant and partial sciatic nerve ligation (PSNL). In the pleurisy model, LG reduced the number of leukocytes and the levels of TNF-α and IL-1β. It also inhibited cinnamaldehyde and menthol-induced nociceptive behavior. The pain threshold in mechanical and thermal hyperalgesia was increased and paw edema was decreased in models of inflammatory and neuropathic pain. PSNL increased inflammatory protein contents and LG and LG-βCD restored the protein contents of TNF-α, NF-κB, and PKA, but not IL-1β and IL-10. LG inhibited voltage gated Ca²⁺ channels from DRG neurons. Our results suggested that LG or LG-βCD produce anti-hyperalgesic effect in chronic pain models through reductions in TNF-α levels and PKA, and inhibited voltage-gated calcium channels and may be innovative therapeutic agents for the management of NP.

The granulopoietic cytokine granulocyte colony-stimulating factor (G-CSF) induces pain: analgesia by rutin

Rutin is a glycone form of the flavonol quercetin and it reduces inflammatory pain in animal models. Therapy with granulocyte colony-stimulating factor (G-CSF) is known by the pain caused as its main side effect. The effect of rutin and its mechanisms of action were evaluated in a model of hyperalgesia induced by G-CSF in mice. The mechanical hyperalgesia induced by G-CSF was reduced by treatment with rutin in a dose-dependent manner. Treatment with both rutin + morphine or rutin + indomethacin, at doses that are ineffectual per se, significantly reduced the pain caused by G-CSF. The nitric oxide (NO)-cyclic guanosine monophosphate (cGMP)-protein kinase G (PKG)-ATP-sensitive potassium channel (K_ATP) signaling pathway activation is one of the analgesic mechanisms of rutin. Rutin also reduced the pro-hyperalgesic and increased anti-hyperalgesic cytokine production induced by G-CSF. Furthermore, rutin inhibited the activation of the nuclear factor kappa-light-chain enhancer of activated B cells (NFκB), which might explain the inhibition of the cytokine production. Treatment with rutin upregulated the decreased mRNA expression of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) combined with enhancement of the mRNA expression of the Nrf2 downstream target heme oxygenase (HO-1). Intraperitoneal (i.p.) treatment with rutin did not alter the mobilization of neutrophils induced by G-CSF. The analgesia by rutin can be explained by: NO-cGMP-PKG-K_ATP channel signaling activation, inhibition of NFκB and triggering the Nrf2/HO-1 pathway. The present study demonstrates rutin as a promising pharmacological approach to treat the pain induced by G-CSF without impairing its primary therapeutic benefit of mobilizing hematopoietic progenitor cells into the blood.

Repurposing of the Nootropic Drug Vinpocetine as an Analgesic and Anti-Inflammatory Agent: Evidence in a Mouse Model of Superoxide Anion-Triggered Inflammation

Clinically active drugs for the treatment of acute pain have their prescription limited due to the significant side effects they induce. An increase in reactive oxygen species (ROS) has been linked to several conditions, including inflammation and pain processing. Therefore, new or repurposed drugs with the ability of reducing ROS-triggered responses are promising candidates for analgesic drugs. Vinpocetine is a clinically used nootropic drug with antioxidant, anti-inflammatory, and analgesic properties. However, the effects of vinpocetine have not been investigated in a model with a direct relationship between ROS, inflammation, and pain. Based on that, we aimed to investigate the effects of vinpocetine in a model of superoxide anion-induced pain and inflammation using potassium superoxide (KO₂) as a superoxide anion donor to trigger inflammation and pain. In the KO₂ model, vinpocetine dose-dependently reduced pain-like behaviors (spontaneous pain and hyperalgesia), paw edema, and neutrophil and mononuclear cell recruitment to the paw skin (assessed by H&E staining, fluorescence, and enzymatic assays) and to the peritoneal cavity. Vinpocetine also restored tissue endogenous antioxidant ability and Nrf2 and Ho-1 mRNA expression and reduced superoxide anion production and gp91^phox mRNA expression. We also observed the inhibition of IκBα degradation by vinpocetine, which demonstrates a reduction in the activation of NF-κB explaining the diminished production of IL-33, IL-1β, and TNF-α. Collectively, our data show that vinpocetine alleviates pain and inflammation induced by KO₂, which is a mouse model with a direct role of ROS in triggering pain and other inflammatory phenomena. Thus, the results suggest the repurposing of vinpocetine as an anti-inflammatory and analgesic drug.

Sesquiterpene lactones from Ambrosia arborescens Mill. inhibit pro-inflammatory cytokine expression and modulate NF-κB signaling in human skin cells

BACKGROUND

Ambrosia arborescens has been used in Andean traditional medicine to reduce problems associated with various inflammatory diseases and conditions, although the underlying mechanism is unknown.

HYPOTHESIS/PURPOSE

The sesquiterpene lactones (SLs) coronopilin and damsin, which are major secondary metabolites of A. arborescens, have anti-inflammatory activity by attenuation of IL-6 and MCP-1 expression and inhibition of NF-κB in human dermal fibroblasts (HDFa) and human keratinocytes (HaCaT).

STUDY DESIGN

In order to confirm a high concentration of damsin and coronopilin in the plant material, a quantitative method was developed. The effect of the pure compounds on cytokine and NF-κB expression was examined, as well as their effects on HDFa and HaCaT cell morphology and viability.

METHODS

Coronopilin and damsin were quantified by HPLC-DAD analysis, from EtOAc extracts of the aerial parts of A. arborescens. Cell morphology was investigated by phase-contrast microscopy and cell viability by the MTT assay. IL-6 and MCP-1 cytokine gene expression was assessed by quantitative real-time RT-PCR in LPS stimulated cells. The NF-κB pathway was studied through western blotting of the phosphorylated forms of p65 and p50/p105, as well as the non-phosphorylated IκB. Dexamethasone was used as positive control.

RESULTS

Dry aerial parts contained 12.3  mg/g and 13.4  mg/g of coronopilin and damsin, respectively. Treatment with either compound (1-10 µM) for 24  h attenuated LPS-induced mRNA expression of the pro-inflammatory cytokine IL-6 and the chemokine MCP-1 in HDFa cells. The down-regulation of MCP-1 mRNA induced by coronopilin and damsin was confirmed on the protein level. Damsin reduced phosphorylated p65 and p105 subunits in HDFa cells. Neither coronopilin nor damsin affected HDFa cell morphology and viability within the used concentration range (1-10 µM). Also, in HaCaT cells, treatment with damsin (1-10 µM) for 24  h inhibited the MCP-1 expression, and damsin thereby attenuated cytokine expression both in HDFa and HaCaT cells.

CONCLUSION

We show that coronopilin and damsin from A. arborescens inhibit pro-inflammatory IL-6 and MCP-1 expression in human skin cells via NF-κB inhibition, suggesting that they may be useful for antagonizing inflammatory conditions of the human skin.

Budlein A, a Sesquiterpene Lactone From Viguiera robusta, Alleviates Pain and Inflammation in a Model of Acute Gout Arthritis in Mice

Background: Gout is the most common inflammatory arthritis worldwide. It is a painful inflammatory disease induced by the deposition of monosodium urate (MSU) crystals in the joints and peri-articular tissues. Sesquiterpene lactones (SLs) are secondary metabolite biosynthesized mainly by species from the family Asteraceae. It has been demonstrated that SLs present anti-inflammatory, analgesic, antitumoral, antiparasitic, and antimicrobial activities. In this study, we aimed at evaluating the efficacy of the SL budlein A in a model of acute gout arthritis in mice. Methods: Experiments were conducted in male Swiss or male LysM-eGFP mice. Animals were treated with budlein A (1 or 10 mg/kg) or vehicle 30 min before stimulus with MSU (100 μg/10 μL, intra-articular). Knee joint withdrawal threshold and edema were evaluated using electronic von Frey and caliper, respectively, 1-15 h after MSU injection. Leukocyte recruitment was determined by counting cells (Neubauer chamber), H&E staining, and using LysM-eGFP mice by confocal microscopy. Inflammasome components, Il-1β, and Tnf-α mRNA expression were determined by RT-qPCR. IL-1β and TNF-α production (in vitro) and NF-κB activation (in vitro and in vivo) were evaluated by ELISA. In vitro analysis using LPS-primed bone marrow-derived macrophages (BMDMs) was performed 5 h after stimulation with MSU crystals. For these experiments, BMDMs were either treated or pre-treated with budlein A at concentrations of 1, 3, or 10 μg/mL. Results: We demonstrated that budlein A reduced mechanical hypersensitivity and knee joint edema. Moreover, it reduced neutrophil recruitment, phagocytosis of MSU crystals by neutrophils, and Il-1β and Tnf-α mRNA expression in the knee joint. In vitro, budlein A decreased TNF-α production, which might be related to the inhibition of NF-κB activation. Furthermore, budlein A also reduced the IL-1β maturation, possibly by targeting inflammasome assembly in macrophages. Conclusion: Budlein A reduced pain and inflammation in a model of acute gout arthritis in mice. Therefore, it is likely that molecules with the ability of targeting NF-κB activation and inflammasome assembly, such as budlein A, are interesting approaches to treat gout flares.

Ginsenoside metabolite compound K exerts anti-inflammatory and analgesic effects via downregulating COX2

OBJECTIVE

The present study aimed to evaluate the anti-inflammatory and analgesic activities of the ginsenoside metabolite compound K (CK) and its mechanisms.

METHODS

Mice model of xylene-induced ear swelling and rat model of carrageenan-induced paw swelling were used to evaluate the effect of CK on acute inflammation. The analgesic effect of CK was evaluated on heat-, acetic acid-, and carrageenan-induced hyperalgesia. The levels of prostaglandin E2 (PGE2), cyclooxygenase-1 (COX-1), and COX-2 in carrageenan-induced rat paw swelling and gastric mucosa were detected by enzyme-linked immunosorbent assay (ELISA). COX-1 and COX-2 expressions in carrageenan-induced rat paw swelling and gastric mucosa were detected by western blotting. In vitro effect of CK (10^-9, 10^-8, 10^-7, 10^-6, 10^-5 M) on COX-1 and COX-2 activities was evaluated by measuring the production of 6-keto-PGF1α and PGE2 in rat peritoneal macrophages.

RESULTS

CK at doses of 7, 14, 28, 56, 112, and 224 mg/kg alleviated xylene-induced ear oedema, whereas CK at 40, 80, and 160 mg/kg alleviated carrageenan-induced paw oedema. CK at 224 mg/kg showed an analgesic effect against acetic acid-induced pain. CK at 40, 80, and 160 mg/kg significantly increased rat inflammatory pain threshold, but had no effect on heat-induced pain threshold. CK at 10, 20, 40, 80, and 160 mg/kg reduced PGE2 level in the paw tissue, but showed no effect on that in the gastric mucosa. CK at 20, 40, 80, and 160 mg/kg decreased COX-2 expression in the paw tissue and gastric mucosa, but exhibited no effect on COX-1 expression or on COX-1 and COX-2 activities.

CONCLUSION

CK exerted anti-inflammatory and analgesic effects, possibly by reducing the catalytic synthesis of PGE2 via downregulation of COX-2 expression.

Physicochemical characterization, the Hirshfeld surface, and biological evaluation of two meloxicam compounding pharmacy samples

Meloxicam (MLX) is an anti-inflammatory drug susceptible to variations and crystalline transitions. In compounding pharmacies, the complete crystallographic evaluation of the raw material is not a routine procedure. We performed a complete crystallographic characterization of aleatory raw MLX samples from compounding pharmacies. X-ray diffraction indicated the presence of two crystalline forms in one sample. DSC experiments suggested that crystallization, or a crystal transition, occurred differently between samples. The FTIR and ¹H NMR spectra showed characteristic assignments. ¹³C solid-state NMR spectroscopy indicated the presence of more than one phase in a sample from pharmacy B. The Hirshfeld surface analysis, with electrostatic potential projection, allowed complete assignment of the UV spectra in ethanol solution. The polymorph I of meloxicam was more active than polymorph III in an experimental model of acute inflammation in mice. Our results highlighted the need for complete crystallographic characterization and the separation of freely used raw materials in compounding pharmacies, as a routine procedure, to ensure the desired dose/effect.

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Characterization of meloxicam polymorphs I and III.

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Biological activity evaluation.

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Hirshfeld surface analysis explains experimentally observed solubility differences.

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Meloxicam form I was more effective than form III.

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Adequate quality control based on crystallographic characterization required for raw materials.

倍半萜内酯类治疗肠易激综合征的应用前景

肠易激综合征(irritable bowel syndrome, IBS)是常见的功能性肠道疾病, 以腹痛或腹部不适、排便习惯异常为特征, 其发病机制尚不明确. 依照罗马Ⅲ标准可将其分为腹泻型、便秘型、混合型和未定型4种亚型. 目前临床治疗原则主要是对症治疗, 迄今尚无特效药物能够有效治疗所有类型IBS. 倍半萜内酯类成分是众多药用植物的生物活性成分, 具有广泛生物学活性, 包括抗肿瘤、抗炎镇痛、抗菌等. 本文就倍半萜内酯类成分可改善IBS症状的相关生物学活性, 及其在IBS治疗中的应用前景进行简要综述.

Diosmin reduces chronic constriction injury-induced neuropathic pain in mice

Injury or dysfunction of somatosensory system induces a complex syndrome called neuropathic pain, which still needs adequate pharmacological control. The current pharmacological treatments were in part developed from natural compounds. Flavonoids are natural polyphenolic molecules presenting varied biological activities and low toxicity. The flavonoid diosmin is a safe compound with good tolerability and low toxicity. This study evaluated the antinociceptive effect of diosmin in the sciatic nerve chronic constriction injury (CCI)-induced neuropathic pain model. Male Swiss mice were submitted to CCI and 7 days after, diosmin at 1 or 10 mg/kg was administrated intraperitoneally. Mechanical (electronic analgesimeter) and thermal (hot plate) hyperalgesia were evaluated 1-24 h after treatment. The role of the NO/cGMP/PKG/KATP channel signaling pathway in the analgesic effect of diosmin was evaluated using the pretreatment with L-NAME (an inhibitor of NOS), ODQ (an inhibitor of soluble guanylate cyclase), KT5823 (an inhibitor of PKG), or glibenclamide (an ATP-sensitive K+ channels blocker). Single treatment with diosmin inhibited in a dose-dependent manner CCI-induced mechanical and thermal hyperalgesia by activating the NO/cGMP/PKG/KATP channel signaling pathway and inhibiting spinal cord cytokine (Il-1β and Il-33/St2) and glial cells activation (microglia - Iba-1, oligodendrocytes - Olig2) mRNA expression markers. Daily treatment during 7 days with diosmin inhibited CCI-induced mechanical and thermal hyperalgesia by inhibiting spinal cord cytokine (Il-1β, Tnfα, and Il-33/St2) and glial cells activation (astrocytes - Gfap, Iba-1, and Olig2) markers mRNA expression. In conclusion, diosmin inhibits neuropathic spinal cord nociceptive mechanisms suggesting this flavonoid as a potential therapeutic molecule to reduce nerve lesion-induced neuropathic pain.

Seasonal variation of the essential oil from two Brazilian native Aldama La Llave (Asteraceae) species

ABSTRACT Aldama arenaria and A. robusta are morphologically similar aromatic species that have seasonal development. The yield and chemical composition of essential oils from aerial and underground vegetative organs of these species were compared to verify the production of volatile metabolites in flowering and dormant phases of development and to identify if there are unique compounds for either species. The major compound in the essential oils from A. arenaria leaves was palustrol (16.22%) and for aerial stems was limonene (15.3%), whereas limonene (11.16%) and α-pinene (19.64%) were the major compounds for leaves and aerial stems from A. robusta, respectively. The major compound for the underground organs was α-pinene, in both species and phenological stages. High amounts of diterpenes were found especially for A. arenaria essential oils. Each analyzed species presented unique compounds, which can provide a characteristic chemical profile for both species helping to solve their taxonomic problems. This study characterized for the first time the yield and essential oil composition of A. arenaria and A. robusta, which have medicinal potential, and some of the compounds in their essential oils are unique to each one and may be useful in helping the correct identification of them.

Effects of budlein A on human neutrophils and lymphocytes

OBJECTIVE

In this study, we evaluated whether budlein A modulates the activation of innate and adaptive immune cells such as neutrophils and lymphocytes.

MATERIAL AND METHODS

Our research group has investigated several plant species and several compounds have been isolated, identified, and their medical potential evaluated. Budlein A is a SL isolated from the species Aldama buddlejiformis and A. robusta (Asteraceae) and shows anti-inflammatory and anti-nociceptive activities. Advances in understanding how plant-derived substances modulate the activation of innate and adaptive immune cells have led to the development of new therapies for human diseases.

RESULTS

Budlein A inhibited MPO activity, IL-6, CXCL8, IL-10, and IL-12 production and induces neutrophil apoptosis. In contrast, budlein A inhibited lymphocyte proliferation and IL-2, IL-10, TGF-β, and IFN-γ production, but it did not lead to cell death.

CONCLUSIONS

Collectively, our results indicate that budlein A shows distinct immunomodulatory effects on immune cells.

Capitate glandular trichomes in Aldama discolor (Heliantheae - Asteraceae): morphology, metabolite profile and sesquiterpene biosynthesis

The capitate glandular trichome is the most common type described in Asteraceae species. It is known for its ability to produce various plant metabolites of ecological and economic importance, among which sesquiterpene lactones are predominant. In this paper, we applied microscopy, phytochemical and molecular genetics techniques to characterise the capitate glandular trichome in Aldama discolor, a native Brazilian species of Asteraceae, with pharmacological potential. It was found that formation of trichomes on leaf primordia of germinating seeds starts between 24 h and 48 h after radicle growth indicates germination. The start of metabolic activity of trichomes was indicated by separation of the cuticle from the cell wall of secretory cells at the trichome tip after 72 h. This coincided with the accumulation of budlein A, the major sesquiterpene lactone of A. discolor capitate glandular trichomes, in extracts of leaf primordia after 96 h. In the same timeframe of 72-96 h post-germination, gene expression studies showed up-regulation of the putative germacrene A synthase (pGAS2) and putative germacrene A oxidase (pGAO) of A. discolor in the transcriptome of these samples, indicating the start of sesquiterpene lactone biosynthesis. Sequencing of the two genes revealed high similarity to HaGAS and HaGAO from sunflower, which shows that key steps of this pathway are highly conserved. The processes of trichome differentiation, metabolic activity and genetic regulation in A. discolor and in sunflower appear to be typical for other species of the subtribe Helianthinae.

Pimaradienoic Acid Inhibits Carrageenan-Induced Inflammatory Leukocyte Recruitment and Edema in Mice: Inhibition of Oxidative Stress, Nitric Oxide and Cytokine Production

Pimaradienoic acid (PA; ent-pimara-8(14),15-dien-19-oic acid) is a pimarane diterpene found in plants such as Vigueira arenaria Baker (Asteraceae) in the Brazilian savannas. Although there is evidence on the analgesic and in vitro inhibition of inflammatory signaling pathways, and paw edema by PA, its anti-inflammatory effect deserves further investigation. Thus, the objective of present study was to investigate the anti-inflammatory effect of PA in carrageenan-induced peritoneal and paw inflammation in mice. Firstly, we assessed the effect of PA in carrageenan-induced leukocyte recruitment in the peritoneal cavity and paw edema and myeloperoxidase activity. Next, we investigated the mechanisms involved in the anti-inflammatory effect of PA. The effect of PA on carrageenan-induced oxidative stress in the paw skin and peritoneal cavity was assessed. We also tested the effect of PA on nitric oxide, superoxide anion, and inflammatory cytokine production in the peritoneal cavity. PA inhibited carrageenan-induced recruitment of total leukocytes and neutrophils to the peritoneal cavity in a dose-dependent manner. PA also inhibited carrageenan-induced paw edema and myeloperoxidase activity in the paw skin. The anti-inflammatory mechanism of PA depended on maintaining paw skin antioxidant activity as observed by the levels of reduced glutathione, ability to scavenge the ABTS cation and reduce iron as well as by the inhibition of superoxide anion and nitric oxide production in the peritoneal cavity. Furthermore, PA inhibited carrageenan-induced peritoneal production of inflammatory cytokines TNF-α and IL-1β. PA presents prominent anti-inflammatory effect in carrageenan-induced inflammation by reducing oxidative stress, nitric oxide, and cytokine production. Therefore, it seems to be a promising anti-inflammatory molecule that merits further investigation.

Naringenin reduces inflammatory pain in mice

Naringenin is a flavonoid widely consumed by humans that present anti-inflammatory activity and low toxicity. Recently, the analgesic effect of naringenin has been demonstrated in neuropathic pain models. Herein, we tested the analgesic effects of naringenin in several models of inflammatory pain. Mice received treatment with naringenin (16.7-150 mg/kg, per oral), or with the controls anti-inflammatory drugs indomethacin (5 mg/kg, intraperitoneal) or dipyrone (80 mg/kg, intraperitoneal) prior the inflammatory stimuli injection. For acute pain, we used acetic acid- and PBQ-induced visceral pain (abdominal writhings), and formalin-, capsaicin-, and CFA-induced paw flinching and licking. By using an electronic version of von Frey filaments, we also investigated the effects of naringenin in pain intensity to a mechanical stimulus (mechanical hyperalgesia) after carrageenan, capsaicin, CFA, or PGE2 intraplantar injection. Naringenin (50 mg/kg) reduced acute pain behaviors induced by all tested stimuli, including both phases of formalin test, suggesting a direct nociceptor modulatory effect of this compound besides its anti-inflammatory activity. Accordingly, naringenin also inhibited the increased sensitivity to mechanical stimulus induced by carrageenan, capsaicin, and PGE2. Daily treatment with naringenin during 7 days also reduced CFA-induced mechanical hyperalgesia without gastric or hepatic toxicity. The mechanisms of naringenin involve the inhibition of carrageenan-induced oxidative stress, hyperalgesic cytokines (IL-33, TNF-α, and IL-1β) production and NF-κB activation in the paw skin. Naringenin also activated the analgesic NO-cyclic GMP-PKG-ATP sensitive K(+) channel signaling pathway to inhibit carrageenan-induced mechanical hyperalgesia and neutrophil recruitment. These results suggest that naringenin inhibits both inflammatory pain and neurogenic inflammation.

Dual effects on constipation and diarrhea: protective potential of Radix Inulae lactones on irritable bowel syndrome

Radix Inulae (RI) is commonly used to treat upper body pain, emesis, diarrhea and parasitic diseases in China.

Peripheral NLCR4 inflammasome participates in the genesis of acute inflammatory pain

Inflammatory hyperalgesia is a complex process that depends on the sensitization of primary nociceptive neurons triggered by proinflammatory mediators, such as interleukin 1β (IL-1β). Recently, the peripheral activation of caspase-1 (previously known as IL-1β-converting enzyme) was implicated in the induction of acute inflammatory pain by promoting the processing of IL-1β from its precursor form, pro-IL-1β. Caspase-1 activation in several systems requires the assembly of an intracellular molecular platform called an inflammasome. Inflammasomes consist of 1 nucleotide-binding oligomerization domain-like receptor (NLR), the adapter molecule apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (ASC), and caspase-1. NLRP3 and NLRC4 inflammasomes are well described. However, the identity of the inflammasome that is involved in the peripheral activation of caspase-1 that accounts for acute inflammatory hyperalgesia has not been described. The present findings demonstrated that mice deficient in NLRC4 or ASC, but not in NLRP3, present reduced mechanical and thermal acute inflammatory hyperalgesia induced by carrageenan. The reduced hyperalgesia was accompanied by significant impairments in the levels of mature forms of IL-1β (p17) and caspase-1 (p20) compared to wild-type mice at the inflammatory site. Therefore, these results identified the inflammasome components NLRC4 and ASC as the molecular platform involved in the peripheral activation of caspase-1 and IL-1β maturation, which are responsible for the induction of acute inflammatory pain. In conclusion, our study provides new therapeutic targets for the control of acute inflammatory pain.

Vanillic Acid Inhibits Inflammatory Pain by Inhibiting Neutrophil Recruitment, Oxidative Stress, Cytokine Production, and NFκB Activation in Mice

Vanillic acid (1) is a flavoring agent found in edible plants and fruits. It is an oxidized form of vanillin. Phenolic compounds form a substantial part of plant foods used as antioxidants with beneficial biological activities. These compounds have received considerable attention because of their role in preventing human diseases. Especially, 1 presents antibacterial, antimicrobial, and chemopreventive effects. However, the mechanisms by which 1 exerts its anti-inflammatory effects in vivo are incompletely understood. Thus, the effect of 1 was evaluated in murine models of inflammatory pain. Treatment with 1 inhibited the overt pain-like behavior induced by acetic acid, phenyl-p-benzoquinone, the second phase of the formalin test, and complete Freund's adjuvant (CFA). Treatment with 1 also inhibited carrageenan- and CFA-induced mechanical hyperalgesia, paw edema, myeloperoxidase activity, and N-acetyl-β-D-glucosaminidase activity. The anti-inflammatory mechanisms of 1 involved the inhibition of oxidative stress, pro-inflammatory cytokine production, and NFκB activation in the carrageenan model. The present study demonstrated 1 presents analgesic and anti-inflammatory effects in a wide range of murine inflammation models, and its mechanisms of action involves antioxidant effects and NFκB-related inhibition of pro-inflammatory cytokine production.

A Metabolomic Approach to Target Compounds from the Asteraceae Family for Dual COX and LOX Inhibition

The application of metabolomics in phytochemical analysis is an innovative strategy for targeting active compounds from a complex plant extract. Species of the Asteraceae family are well-known to exhibit potent anti-inflammatory (AI) activity. Dual inhibition of the enzymes COX-1 and 5-LOX is essential for the treatment of several inflammatory diseases, but there is not much investigation reported in the literature for natural products. In this study, 57 leaf extracts (EtOH-H₂O 7:3, v/v) from different genera and species of the Asteraceae family were tested against COX-1 and 5-LOX while HPLC-ESI-HRMS analysis of the extracts indicated high diversity in their chemical compositions. Using O2PLS-DA (R² > 0.92; VIP > 1 and positive Y-correlation values), dual inhibition potential of low-abundance metabolites was determined. The O2PLS-DA results exhibited good validation values (cross-validation = Q² > 0.7 and external validation = P² > 0.6) with 0% of false positive predictions. The metabolomic approach determined biomarkers for the required biological activity and detected active compounds in the extracts displaying unique mechanisms of action. In addition, the PCA data also gave insights on the chemotaxonomy of the family Asteraceae across its diverse range of genera and tribes.

Anti-septic effects of fisetin in vitro and in vivo

Sepsis is a state of disrupted inflammatory homeostasis that is initiated by infection. High mobility group box 1 (HMGB1) protein acting as a late mediator of severe vascular inflammatory conditions, such as sepsis and endothelial cell protein C receptor (EPCR), is involved in vascular inflammation. Fisetin, an active compound from the family Fabaceae, was reported to have antiviral, neuroprotective, and anti-inflammatory activities. Here, we determined the anti-septic effects of fisetin on HMGB1-mediated inflammatory responses and on the shedding of EPCR in vitro and in vivo, for the first time. First, we monitored the effects of post-treatment fisetin on lipopolysaccharide (LPS) and cecal ligation and puncture (CLP)-mediated release of HMGB1 and HMGB1-mediated regulation of pro-inflammatory responses in human umbilical vein endothelial cells (HUVECs) and septic mice. Post-treatment fisetin was found to suppress LPS-mediated release of HMGB1 and HMGB1-mediated cytoskeletal rearrangements. Fisetin also inhibited HMGB1-mediated hyperpermeability and leukocyte migration in septic mice. Fisetin induced potent inhibition of phorbol-12-myristate 13-acetate (PMA) and CLP-induced EPCR. Fisetin also inhibited the expression and activity of tumor necrosis factor-α converting enzyme, induced by PMA in endothelial cells. In addition, fisetin inhibited the production of tumor necrosis factor-α and the activation of AKT, nuclear factor-κB, and extracellular regulated kinases 1/2 by HMGB1 in HUVECs. Fisetin also down-regulated CLP-induced release of HMGB1, production of interleukin 1β, and reduced septic mortality. Collectively, these results suggest that fisetin may be a candidate therapeutic agent for the treatment of vascular inflammatory diseases via inhibition of the HMGB1 signaling pathway.

Exendin-4 inhibits HMGB1-induced inflammatory responses in HUVECs and in murine polymicrobial sepsis

Exendin-4 (EX4) has been reported to attenuate myocardial ischemia and reperfusion (I/R) injury and inflammatory and oxidative responses. Nuclear DNA-binding protein high-mobility group box 1 (HMGB1) protein acts as a late mediator of severe vascular inflammatory conditions. However, the effect of EX4 on HMGB1-induced inflammatory response has not been studied. First, we accessed this question by monitoring the effects of posttreatment EX4 on lipopolysaccharide (LPS) and cecal ligation and puncture (CLP)-mediated release of HMGB1 and HMGB1-mediated regulation of proinflammatory responses in human umbilical vein endothelial cells (HUVECs) and septic mice. Posttreatment EX4 was found to suppress LPS-mediated release of HMGB1 and inhibited HMGB1-mediated hyperpermeability and leukocyte migration in septic mice. EX4 also induced downregulation of CLP-induced release of HMGB1, production of IL-6, and mortality. Collectively, these results suggest that EX4 may be regarded as a candidate therapeutic agent for treatment of vascular inflammatory diseases via inhibition of the HMGB1 signaling pathway.

IL-33/ST2 signalling contributes to carrageenin-induced innate inflammation and inflammatory pain: role of cytokines, endothelin-1 and prostaglandin E2

BACKGROUND AND PURPOSE

IL-33 signals through ST2 receptors and induces adaptive and innate inflammation. IL-33/ST2 is involved in adaptive inflammation-induced pain. Here, we have investigated the contribution of IL-33/ST2-triggered mechanisms to carrageenin-induced innate inflammation.

EXPERIMENTAL APPROACH

Carrageenin- and IL-33-induced inflammatory responses were assessed in BALB/c- (WT) and ST2-deficient ((-/-) ) mice as follows: oedema (plethysmometer), myeloperoxidase activity (colorimetric assay), mechanical hyperalgesia (electronic version of von Frey filaments), cytokine levels (ELISA), PGE2 (RIA), mRNA expression (quantitative PCR), drug treatments targeting leukocyte recruitment (fucoidin), TNF-α (infliximab), CXCL1 (antibody to CXCL1), IL-1 (IL-1ra), endothelin ETA (clazosentan) and ETB (BQ788) receptors and COX (indomethacin).

KEY RESULTS

Carrageenin injection increased ST2 and IL-33 mRNA expression and IL-33 production in paw skin samples. Carrageenin-induced paw oedema, hyperalgesia and myeloperoxidase activity were reduced in ST2(-/-) compared with WT mice, effects mimicked by IL-33 injection in the paw. Furthermore, IL-33-induced hyperalgesia was reduced by fucoidin suggesting a role for recruited leukocytes in its hyperalgesic effect. IL-33-induced hyperalgesia in naïve mice was reduced by treatments targeting TNF, CXCL1, IL-1, endothelin receptors and COX while carrageenin-induced ST2-dependent TNF-α, CXCL1, IL-1β, IL-10 and PGE2 production and preproET-1 mRNA expression. Combining IL-33 and carrageenin at doses that were ineffective as single treatment induced significant hyperalgesia, oedema, myeloperoxidase activity and cytokine production in a ST2-dependent manner.

CONCLUSIONS AND IMPLICATIONS

IL-33/ST2 signalling triggers the production of inflammatory mediators contributing to carrageenin-induced inflammation. These data reinforces the importance of IL-33/ST2 signalling as a target in innate inflammation and inflammatory pain.

Anti-inflammatory activity of betalain-rich dye of Beta vulgaris: effect on edema, leukocyte recruitment, superoxide anion and cytokine production

We have recently developed betalain-rich beetroot (Beta vulgaris) dye (betalain) to be used in food products. Betalain (30-300 mg/kg) intraperitoneal (i.p.) treatment diminished carrageenan (100 µg/paw)-induced paw edema and neutrophil migration to the paw skin tissue. Betalain (100 mg/kg) treatment by subcutaneous or per oral routes also inhibited the carrageenan-induced paw edema. Importantly, the post-treatment with betalain (100 mg/kg, i.p.) significantly inhibited carrageenan- and complete Freund's adjuvant (10 µl/paw)-induced paw edema. Betalain (100 mg/kg) also reduced carrageenan (500 µg/cavity)-induced recruitment of total leukocytes, including mononuclear cells and neutrophils, as well as increasing vascular permeability in the peritoneal cavity. Furthermore, betalain significantly reduced carrageenan-induced superoxide anion, tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-1β levels in the peritoneal fluid, as well as augmenting IL-10 levels. Therefore, this compound presents prominent anti-inflammatory effect on carrageenan-induced paw edema and peritonitis by reducing the production of superoxide anion and the cytokines TNF-α and IL-1β, in addition to increasing IL-10 levels. These results suggest that betalain shows therapeutic potential that could be utilized in the treatment of inflammation-associated diseases.

The ruthenium nitric oxide donor, [Ru(HEDTA)NO], inhibits acute nociception in mice by modulating oxidative stress, cytokine production and activating the cGMP/PKG/ATP-sensitive potassium channel signaling pathway

Nitric oxide plays an important role in various biological processes including antinociception. The control of its local concentration is crucial for obtaining the desired effect and can be achieved with exogenous nitric oxide-carriers such as ruthenium complexes. Therefore, we evaluated the analgesic effect and mechanism of action of the ruthenium nitric oxide donor [Ru(HEDTA)NO] focusing on the role of cytokines, oxidative stress and activation of the cyclic guanosine monophosphate/protein kinase G/ATP-sensitive potassium channel signaling pathway. It was observed that [Ru(HEDTA)NO] inhibited in a dose-dependent (1-10 mg/kg) manner the acetic acid-induced writhing response. At the dose of 1 mg/kg, [Ru(HEDTA)NO] inhibited the phenyl-p-benzoquinone-induced writhing response, and formalin- and complete Freund's adjuvant-induced licking and flinching responses. Systemic and local treatments with [Ru(HEDTA)NO] also inhibited the carrageenin-induced mechanical hyperalgesia and increase of myeloperoxidase activity in paw skin samples. Mechanistically, [Ru(HEDTA)NO] inhibited carrageenin-induced production of the hyperalgesic cytokines tumor necrosis factor-α and interleukin-1β, and decrease of reduced glutathione levels. Furthermore, the inhibitory effect of [Ru(HEDTA)NO] in the carrageenin-induced hyperalgesia and myeloperoxidase activity was prevented by the treatment with ODQ (soluble guanylyl cyclase inhibitor), KT5823 (protein kinase G inhibitor) and glybenclamide (ATP-sensitive potassium channel inhibitor), indicating that [Ru(HEDTA)NO] inhibits inflammatory hyperalgesia by activating the cyclic guanosine monophosphate/protein kinase G/ATP-sensitive potassium channel signaling pathway, respectively. These results demonstrate that [Ru(HEDTA)NO] exerts its analgesic effect in inflammation by inhibiting pro-nociceptive cytokine production, oxidative imbalance and activation of the nitric oxide/cyclic guanosine monophosphate/protein kinase G/ATP-sensitive potassium channel signaling pathway in mice.

Microbial transformations of halolactones with p-menthane system

Biologically active piperitone-derived racemic iodo-, bromo- and chlorolactones (1-3) were transformed with the use of microbial enzymatic systems. Four strains of filamentous fungi Absidia glauca AM254, Absidia cylindrospora AM336, Mortierella vinaceae AM149 and Nigrospora oryzae AM8 transformed halolactones (1-3) to four new halohydroxylactones (4-7). In all biotransformations the hydroxy group was incorporated in inactivated methine carbon atom at isopropyl substituent. In N. oryzae AM8 culture the bromolactone with additional hydroxy group in α-position, relative to CO bond in γ-lactone ring, was also formed as a product. The structures of new compounds were established on the basis of spectral data.

Factor Xa inhibits HMGB1-induced septic responses in human umbilical vein endothelial cells and in mice

Nuclear DNA-binding protein high mobility group box 1 (HMGB1) acts as a late mediator of severe vascular inflammatory conditions, such as sepsis. Activated factor X (FXa) is an important player in the coagulation cascade responsible for thrombin generation, and it influences cell signalling in various cell types by activating protease-activated receptors (PARs). However, the effect of FXa on HMGB1-induced inflammatory response has not been studied. First, we addressed this issue by monitoring the effects of post-treatment with FXa on lipopolysaccharide (LPS)- and cecal ligation and puncture (CLP)-mediated release of HMGB1 and HMGB1-mediated regulation of pro-inflammatory responses in human umbilical vein endothelial cells (HUVECs) and septic mice. Post-treatment with FXa was found to suppress LPS-mediated release of HMGB1 and HMGB1-mediated cytoskeletal rearrangements. FXa also inhibited HMGB1-mediated hyperpermeability and leukocyte migration in septic mice. In addition, FXa inhibited the production of tumour necrosis factor-α and interleukin (IL)-1β. FXa also facilitated the downregulation of CLP-induced release of HMGB1, production of IL-6, and mortality. Collectively, these results suggest that FXa may be regarded as a candidate therapeutic agent for treating vascular inflammatory diseases by inhibiting the HMGB1 signalling pathway.

Anethole and eugenol reduce in vitro and in vivo leukocyte migration induced by fMLP, LTB4, and carrageenan

The aim of this study was to investigate the effect of anethole (AN) and eugenol (EUG) on leukocyte migration using in vitro chemotaxis and in situ microcirculation assays. BALB/c mice were used for the in vitro chemotaxis assay, and Wistar rats for the in situ microcirculation assay. We evaluated (a) the in vitro leukocyte migration in response to chemotactic factors (formyl-methionyl-leucyl-phenylalanine [fMLP] and leukotriene B4 [LTB4]) and (b) the rolling, adhesion, and migration of leukocytes induced by an injection of carrageenan (100 µg/cavity) into the scrotum of the animal. In the in vitro chemotaxis assay, AN and EUG at doses of 1, 3, 9, and 27 µg/ml significantly inhibited leukocyte migration when stimulated by the chemotactic agents fMLP and LTB4. In the in situ microcirculation assay, AN at doses of 125 and 250 mg/kg and EUG at a dose of 250 mg/kg significantly decreased the number of leukocytes that rolled, adhered, and migrated to perivascular tissue. The results indicate that AN and EUG exert inhibitory effects on leukocyte migration, highlighting their possible use to diminish excessive leukocyte migration in the inflammatory process.

Andrographolide inhibits HMGB1-induced inflammatory responses in human umbilical vein endothelial cells and in murine polymicrobial sepsis

AIM

Nuclear DNA-binding protein high-mobility group box 1 (HMGB1) protein acts as a late mediator of severe vascular inflammatory conditions, such as septic shock, upregulating pro-inflammatory cytokines. Andrographolide (AG) is isolated from the plant of Andrographis paniculata and used as a folk medicine for treatment of viral infection, diarrhoea, dysentery and fever. However, the effect of AG on HMGB1-induced inflammatory response has not been studied.

METHODS

Firstly, we accessed this question by monitoring the effects of post-treatment AG on lipopolysaccharide (LPS) and caecal ligation and puncture (CLP)-mediated release of HMGB1 and HMGB1-mediated regulation of pro-inflammatory responses in human umbilical vein endothelial cells (HUVECs) and septic mice.

RESULTS

Post-treatment AG was found to suppress LPS-mediated release of HMGB1 and HMGB1-mediated cytoskeletal rearrangements. AG also inhibited HMGB1-mediated hyperpermeability and leucocyte migration in septic mice. In addition, AG inhibited production of tumour necrosis factor-α (TNF-α) and activation of AKT, nuclear factor-κB (NF-κB) and extracellular-regulated kinases (ERK) 1/2 by HMGB1 in HUVECs. AG also induced downregulation of CLP-induced release of HMGB1, production of interleukin (IL) 1β/6/8 and mortality.

CONCLUSION

Collectively, these results suggest that AG may be regarded as a candidate therapeutic agent for the treatment of vascular inflammatory diseases via inhibition of the HMGB1 signalling pathway.

A systematic investigation of the fragmentation pattern of two furanoheliangolide C-8 stereoisomers using electrospray ionization mass spectrometry

RATIONALE

Budlein A is a sesquiterpene lactone (STL) with some reported biological activities. Pre-clinical studies to identify in vivo metabolites often employ hyphenated techniques such as liquid chromatography/tandem mass spectrometry (LC/MS/MS). It is also possible to use the fragmentation pattern obtained by Collision-Induced Dissociation (CID) and Higher Energy Collision-Induced Dissociation (HCD) to distinguish between the stereoisomers budlein A and centratherin.

METHODS

The experiments were carried out in the positive mode using four different spectrometers with an electrospray ionization (ESI) source: (a) Waters ACQUITY(®) TQD triple quadrupole mass spectrometer (QqQ), (b) AB Sciex API 4000 QTrap(®) (QqQ), (c) Bruker Daltonics micrOTOF™-Q II (time-of-flight, QTOF), and (d) Thermo Scientific LTQ Orbitrap XL hybrid FTMS (Fourier transform mass spectrometer). Computational chemistry studies helped to identify the protonation sites. The B3LYP/6-31G(d) model furnished the equilibrium geometries and energies.

RESULTS

The stereochemistry (α- or β-orientation) of the centratherin and budlein A side-chain esters influences the fragmentation pattern recorded on QqQ, QTOF, and Orbitrap-HCD. On QqQ, centratherin releases the side chain, to generate the m/z 275 fragment ion, whereas budlein A gives the m/z 83 fragment ion. On QTOF and Orbitrap-HCD, only budlein A affords the m/z 293 and 83 fragment ions, respectively.

CONCLUSIONS

The data suggest that proton migration governs the fragmentation pathways under α- or β-orientation. The difference in the QqQ, QTOF, and Orbitrap-HCD spectral profiles of each isomer can help to distinguish between centratherin and budlein A using MS/MS, which becomes an alternative to nuclear magnetic resonance (NMR) analysis.

Unusual biotransformation products of the sesquiterpene lactone budlein A by Aspergillus species

Biotransformation of chemicals by microorganisms can be effective in increasing chemical diversity. Some fungi have been described to be useful for the biotransformation of sesquiterpene lactones. Nevertheless, in most cases, only minor or simple transformations of functional groups have been observed. Budlein A is a sesquiterpene lactone found in high amounts in American sunflower-like species of the genus Viguiera (Asteraceae). It shows important biological effects like in vitro and in vivo anti-inflammatory activity, as well as cytotoxicity against cancer cell lines. With the aim to obtain potentially bioactive derivatives of budlein A and taking into account that obtaining semi-synthetic analogues is a very complex task, the capability of soil fungi to promote biotransformation was investigated. In this work, the biotransformation of budlein A by the soil fungi Aspergillus terreus and A. niger affording three unusual sesquiterpenoid derivatives with carbon skeletons is reported. The chemical structures of the compounds were elucidated by 1D and 2D NMR spectrometry and HR-ESI-MS. The stereochemistry and molecular conformation of one derivative was assessed by molecular modeling techniques. The fungal metabolites displayed a reduced cytotoxicity against HL-60 cells when compared to the original natural product. The results show the versatility of microbial-catalyzed biotransformations leading to unusual derivatives.