Fagner Carvalho Leite

Nerolidol exhibits antinociceptive and anti-inflammatory activity: involvement of the GABAergic system and proinflammatory cytokines.

Nerolidol, an acyclic sesquiterpene found as a major constituent of several essential oils, has several pharmacological activities, but its action in pain processes has never been studied. The purpose of our research was to evaluate the antinociceptive and anti‐inflammatory activities of nerolidol, as well as possible mechanisms of action, in experimental mouse models of pain. Antinociceptive activity was evaluated using the acetic acid‐induced writhing test, the formalin test, and the hot‐plate test. The nerolidol‐treated group showed lesser acetic acid‐induced abdominal contractions than the control group in all of the three doses tested (200, 300, and 400 mg/kg, p.o.). The formalin test doses of 300 and 400 mg/kg p.o. inhibited licking time, in both the first phase and the second phase. In the hot‐plate test, nerolidol did not alter latency at any of the observed time points. Motor coordination, evaluated through the rotarod test, was not hindered in animals treated with nerolidol. Regarding the mechanism of action, the antinociceptive activity of nerolidol is related to the GABAergic system, and not to the opioidergic or ATP‐sensitive K+ channels. Treatment with nerolidol reduced carrageenan‐induced paw edema. In the model of carrageenan‐induced peritonitis, nerolidol decreased the influx of polymorphonuclear cells and also reduced levels of tumor necrosis factor (TNF‐α) in peritoneal lavage. Nerolidol reduced production of interleukin 1 beta (IL‐1β) in LPS‐stimulated, peritoneal macrophages. Thus, these results showed that nerolidol has antinociceptive activity with possible involvement of the GABAergic system, and anti‐inflammatory activity, attributed to the suppression of TNF‐α and IL‐1β proinflammatory cytokines.

Curine inhibits mast cell-dependent responses in mice.

ETHNOPHARMACOLOGICAL RELEVANCE Curine is a bisbenzylisoquinoline alkaloid and the major constituent isolated from Chondrodendron platyphyllum, a plant that is used to treat inflammatory diseases in Brazilian folk medicine. This study investigates the effectiveness of curine on mast cell-dependent responses in mice. MATERIALS AND METHODS To induce mast cell-dependent responses, Swiss mice were subcutaneously sensitized with ovalbumin (OVA-12 μg/mouse) and Al(OH)3 in a 0.9% NaCl solution. Fifteen days later, the animals were challenged with OVA through different pathways. Alternatively, the animals were injected with compound 48/80 or histamine, and several parameters, including anaphylaxis, itching, edema and inflammatory mediator production, were analyzed. Promethazine, cromoglycate, and verapamil were used as control drugs, and all of the treatments were performed 1h before the challenges. RESULTS Curine pre-treatment significantly inhibited the scratching behavior and the paw edema induced by either compound 48/80 or OVA, and this protective effect was comparable in magnitude with those associated with treatment with either cromoglycate or verapamil. In contrast, curine was a weak inhibitor of histamine-induced paw edema, which was completely inhibited by promethazine. Curine and verapamil significantly inhibited pleural protein extravasations and prostaglandin D2 (PGD2) and cysteinyl leukotrienes (CysLTs) production following allergen-induced pleurisy. Furthermore, like verapamil, curine inhibited the anaphylactic shock caused by either compound 48/80 or an allergen. In in vitro settings, these treatments also inhibited degranulation as well as PGD2 and CysLT production through IgE-dependent activation of the mast cell lineage RBL-2H3. CONCLUSION Curine significantly inhibited immediate allergic reactions through mechanisms more related to mast cell stabilization and activation inhibition than interference with the pro-inflammatory effects of mast cell products. These findings are in line with the hypothesis that the alkaloid curine may be beneficial for the treatment of allergic disorders.

Managing murine food allergy with Cissampelos sympodialis Eichl (Menispermaceae) and its alkaloids

Food allergy is a severe human disease with imminent risk of life. Cissampelos sympodialis (Menispermaceae) is a native Brazilian plant used in Brazilian folk medicine for the treatment of respiratory allergies. In this study the experimental model of food allergy induced by ovalbumin (OVA) was used to determine whether the alcoholic extract of the plant (AFL) and its alkaloids match a therapeutic approach for this disease. Animal weight, diarrhea, OVA-specific IgE levels, inflammatory cell and cytokine profiles, mucus production and proportion of T cells on the mesenteric lymph node (MLN) were evaluated. Warifteine (W) or methyl-warifteine (MW) alkaloids slightly improve diarrhea score independently of AFL and all treatments decreased the OVA-specific IgE levels. Stimulated mesenteric lymph node (MLN) cells in the presence of the alkaloids diminished the IL-12p70 levels independently of IFN-γ or IL-13 secretion. The alkaloids increased the number of Treg cells on MLN and reduced the number of eosinophils and mast cells as well as mucus production in the gut. Therefore, the alkaloids modulate the immune response in food allergy by increasing regulatory T cells in MLN independently of Th1 or Th2 profiles.

Ortho-eugenol exhibits anti-nociceptive and anti-inflammatory activities

Ortho-eugenol is a much used phenylpropanoid whose ability to reduce pain and inflammation has never been studied. Researching ortho-eugenols antinociceptive and anti-inflammatory activity, and its possible mechanisms of action is therefore of interest. The administration of vehicle, ortho-eugenol (50, 75 and 100mg/kg i.p.), morphine (6mg/kg, i.p.) or dexamethasone (2mg/kg, s.c.) occurred 30min before the completion of pharmacological tests. Pretreatment with ortho-eugenol did not change motor coordination test results, but reduced the number of writhes and licking times in the writhing test and glutamate test, respectively. The reaction time from thermal stimulus was significantly increased in the hot plate test after administration of ortho-eugenol. Treatment with yohimbine reversed the antinociceptive effect of ortho-eugenol, suggesting involvement of the adrenergic system. In anti-inflammatory tests, ortho-eugenol inhibited acetic acid induced vascular permeability and leukocyte migration, reducing TNF-α and IL-1β by virtue of its suppression of NF-κB and p38 phosphorylated forms in the peritonitis test. From these results, ortho-eugenol antinociceptive effects mediated by the adrenergic system and anti-inflammatory activity through regulation of proinflammatory cytokines and phosphorylation of NF-kB and p38 become evident for the first time.

Curine, an Alkaloid Isolated from Chondrodendron platyphyllum Inhibits Prostaglandin E2 in Experimental Models of Inflammation and Pain

Curine is a bisbenzylisoquinoline alkaloid that is isolated from Chondrodendron platyphyllum, a plant that is used to treat malaria, inflammation, and pain. Recent reports have demonstrated the antiallergic effects of curine at nontoxic doses. However, its anti-inflammatory and analgesic properties remain to be elucidated. This study investigated the anti-inflammatory and analgesic effects of curine in mice. We analyzed the effects of an oral treatment with curine in the formation of paw edema, vascular permeability, abdominal contortion, licking behavior, and hyperalgesia using different inflammatory stimuli. Curine significantly inhibited the formation of paw edema by decreasing vascular permeability, inhibited the acetic acid-induced writhing response, inhibited the licking behavior during inflammation but not during the neurogenic phase of the formalin test, and inhibited carrageenan-induced hyperalgesia. Finally, curine inhibited prostaglandin E2 production in vitro without affecting cyclooxygenase-2 expression. The effects of curine treatment were similar to the effects of indomethacin, but were different from the effects of morphine treatment, suggesting that the analgesic effects of curine do not result from the direct inhibition of neuronal activation but instead depend on anti-inflammatory mechanisms that, at least in part, result from the inhibition of prostaglandin E2 production. In conclusion, curine presents anti-inflammatory and analgesic effects at nontoxic doses and has the potential for use in anti-inflammatory drug development.

Synthesis, acute toxicity and anti-inflammatory effect of bornyl salicylate, a salicylic acid derivative

Bornyl salicylate (BS) is a salicylic derivative, obtained by sterification of salicylic acid and monoterpene (-)-borneol, and its topical use in inflammatory diseases was described in the early 20th century. It is also known that borneol presents neuroprotective, genoprotective and analgesic properties. The purpose of this study was to evaluate BS in experimental models of acute inflammation. The toxicity of BS was analyzed by measuring water and food intake, weight, mortality and weight of main organs. To assess its anti-inflammatory effect, BS-treated mice were challenged with carrageenan, prostaglandin E2 (PGE2), bradikynin (BK) or histamine (HIS)-induced paw edema, zymosan-induced peritonitis and vascular permeability induced by acetic acid. Nitric oxide (NO) production was analyzed in peritoneal macrophage cultures. There was no sign of acute toxicity of BS in male and female mice. Furthermore, treatment with BS was significantly (p < 0.05) effective in reducing paw edema induced by carrageenan in early and late phases; this effect was related to PGE2 and BK, but HIS independent. Neutrophil migration and cytokine release (TNF-α, IL-1β and IL-6) induced by zymosan and fluid leakage induced by acetic acid were also reduced in BS-treated animals. In vitro, BS (10 µg/mL) reduced NO production in LPS-stimulated macrophages. These data suggest that BS has an anti-inflammatory effect, which is related, at least in part, with decrease of mediators as PGE2, NO and pro-inflammatory cytokines. However, further studies should be done to explore its potential as an anti-inflammatory drug.

Th1-Biased Immunomodulation and In Vivo Antitumor Effect of a Novel Piperine Analogue

Natural products have an important role as prototypes in the synthesis of new anticancer drugs. Piperine is an alkaloid amide with antitumor activity and significant toxicity. Then, the N-(p-nitrophenyl)acetamide piperinoate (HE-02) was synthesized, and tested for toxicological and antitumor effects. The toxicity was evaluated in vitro (on RAW 264.7 cells and mice erythrocytes) and in vivo (acute toxicity in mice). The Ehrlich ascites carcinoma model was used to evaluate the antitumor activity of HE-02 (6.25, 12.5 or 25 mg/kg, intraperitoneally, i.p.), as well as toxicity. HE-02 induced only 5.01% of hemolysis, and reduced the viability of RAW 264.7 cells by 49.75% at 1000 µg/mL. LD50 (lethal dose 50%) was estimated at around 2000 mg/kg (i.p.). HE-02 reduced Ehrlich tumor cell viability and peritumoral microvessels density. There was an increase of Th1 helper T lymphocytes cytokine profile levels (IL-1β, TNF-α, IL-12) and a decrease of Th2 cytokine profile (IL-4, IL-10). Moreover, an increase was observed on reactive oxygen species and nitric oxide production. Weak in vivo toxicological effects were recorded. Our data provide evidence that the piperine analogue HE-02 present low toxicity, and its antitumor effect involves modulation of immune system to a cytotoxic Th1 profile.

Comparison of behavioral, neuroprotective, and proinflammatory cytokine modulating effects exercised by (+)-cis-EC and (−)-cis-EC stereoisomers in a PTZ-induced kindling test in mice

Epoxy‐carvone (EC) has chiral centers that allow generation of stereoisomers, including (+)‐cis‐EC and (−)‐cis‐EC, whose effects in the kindling tests have never been studied. Accordingly, this study aims to comparatively investigate the effect of stereoisomers (+)‐cis‐epoxy‐carvone and (−)‐cis‐epoxy‐carvone on behavioral changes measured in scores, in the levels of cytokines (IL‐1β, IL‐6, and TNFα) and neuronal protection in the face of continuous treatment with pentylenetetrazol. Swiss mice were divided into five groups (n = 10), receiving vehicle, (+) – cis‐EC, (−) – cis‐EC (both at the dose of 30 mg/kg), and diazepam (4 mg/kg). Thirty minutes after the respective treatment was administered to the animals one subconvulsive dose of PTZ (35 mg/kg). Seven subconvulsives treatments were made on alternate days, in which each treatment several parameters were recorded. In the eighth treatment, the animals receiving the highest dose of PTZ (75 mg/kg) and were sacrificed for quantification of cytokines and histopathologic analysis. All drugs were administered by intraperitoneal route. In the kindling test, (+)‐cis‐EC and (−)‐cis‐EC reduced the average scores. The stereoisomer (+)‐cis‐EC decreased levels of proinflammatory cytokines IL‐1β, IL‐6, and TNFα, whereas comparatively (−)‐cis‐EC did not reduce IL‐1β levels. Histopathological analysis of the mice hippocampi undergoing this methodology showed neural protection for treated with (+)‐cis‐EC. The results suggest that the anticonvulsant effect of (+)‐cis‐EC possibly takes place due to reduction of proinflammatory cytokines involved in the epileptogenic process, besides neuronal protection, yet further investigation of the mechanisms involved is required.