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Pain is an unpleasant sensation associated with a wide range of injuries and diseases, and affects approximately 20% of adults in the world. The discovery of new and more effective drugs that can relieve pain is an important research goal in both the pharmaceutical industry and academia. This review describes studies involving antinociceptive activity of essential oils from 31 plant species. Botanical aspects of aromatic plants, mechanisms of action in pain models and chemical composition profiles of the essential oils are discussed. The data obtained in these studies demonstrate the analgesic potential of this group of natural products for therapeutic purposes. [ABSTRACT FROM AUTHOR]

Pentylenetetrazole (PTZ), a tetrazole derivative, is commonly used as a chemical agent to induce neurological disorders and replicate the characteristics of human epileptic seizures in animal models. This review offers a comprehensive analysis of the behavioral, neurophysiological, and neurochemical changes induced by PTZ. The epileptogenic and neurotoxic mechanisms of PTZ are associated with an imbalance between the GABAergic and glutamatergic systems. At doses exceeding 60 mg/kg, PTZ exerts its epileptic effects by non-competitively antagonizing GABA A receptors and activating NMDA receptors, resulting in an increased influx of cations such as Na+ and Ca2+. Additionally, PTZ promotes oxidative stress, microglial activation, and the synthesis of pro-inflammatory mediators, all of which are features characteristic of glutamatergic excitotoxicity. These mechanisms ultimately lead to epileptic seizures and neuronal cell death, which depend on the dosage and method of administration. The behavioral, electroencephalographic, and histological changes associated with PTZ further establish it as a valuable preclinical model for the study of epileptic seizures, owing to its simplicity, cost-effectiveness, and reproducibility. • PTZ-induced seizures replicate human epileptic features in animal models. • PTZ's mechanism involves glutamate excitotoxicity, oxidative stress, and neuroinflammation. • The popularity of PTZ as a model is due to its simplicity, low cost, high reproducibility, and reliability. • PTZ models allow researchers to evaluate the antiepileptic potential of bioactive compounds. [ABSTRACT FROM AUTHOR]

Cinnamic alcohol (CA) is a phenylpropanoid found in the essential oil of the bark of the genus Cinnamomum spp. Schaeff. (Lauraceae Juss.), known as cinnamon. To evaluate the neuroprotective effect of CA and its possible mechanism of action on mice submitted to the pentylenetetrazole (PTZ) induced epileptic seizures model. Behavioral, neurochemical, histomorphometric and immunohistochemistry analysis were carried out. The administration of CA (50–200 mg/kg, i.p., 30 min prior to PTZ and 0.7–25 mg/kg, i.p., 60 min prior to PTZ) increased the latency to seizure onset and the latency to death. The effects observed with CA treatment at 60 min were partially reversed by pretreatment with flumazenil. Furthermore, neurochemical assays indicated that CA reduced the concentration of malondialdehyde and nitrite, while increasing the concentration of reduced glutathione. Finally, histomorphometric and immunohistochemistry analysis revealed a reduction in inflammation and an increase in neuronal preservation in the hippocampi of CA pre-treated mice. Taken together, the results suggest that CA seems to modulate the GABAA receptor, decrease oxidative stress, mitigate neuroinflammation, and reduce cell death processes. • The neuroprotective effect of the cinnamic alcohol is reported. • Cinnamic alcohol increases GABAergic effects in mice. • Cinnamic alcohol presents antioxidant activity. • Cinnamic alcohol prevents neuroinflammation. • Cinnamic alcohol reduces excitotoxic processes induced by PTZ. [ABSTRACT FROM AUTHOR]

Background. Diabetes is a metabolic disease linked to multiple comorbidities, such as low-grade inflammation. β-pinene, a monoterpene commonly found in aromatic plants, is endowed with anti-inflammatory effect and this fact lead us to investigate the possible hypoglycemic, hypolipidemic and anti-inflammatory effects of the monoterpene in the alloxan-induced diabetes experimental model. Methods. Male Wistar rats (200–250 g) were treated orally with β-pinene (25, 50, 100, and 200 mg/kg) or glibenclamide (5 mg/kg), for seven consecutive days. Diabetes was induced by alloxan (40 mg/kg) through the penile vein. On the seventh day of treatment, blood samples were collected for biochemical analysis. The anti-inflammatory effect of β-pinene was evaluated using the carrageenan-induced paw edema model, followed by the carrageenan-induced peritonitis. Results. The treatment with β-pinene decreased plasma glucose, triglyceride, VLDL, LDL, and HDL levels, when compared to those of the control group. In addition, the association β-pinene 10 mg/kg + glibenclamide 2 mg/kg significantly decreased blood glucose, total cholesterol, and triglyceride level. Finally, oral treatment with β-pinene reduced carrageenan-induced paw edema and leukocyte migration in the peritoneum. Taken together, our results indicate that β-pinene shows hypoglycemic and hypolipemic effects, which may involve some common mechanisms of glibenclamide. Besides, the monoterpene presented an anti-inflammatory action in diabetic rats that needs further investigation in order to clarify such effect and its correlation with the alterations observed in plasma parameters of β-pinene-treated diabetic rats. [ABSTRACT FROM AUTHOR]

Spirulina platensis is a cyanobacterium with high protein content and presenting neuroprotective effects. Now, we studied a protein-enriched fraction (SPF), on behavior, neurochemical and immunohistochemical (IHC) assays in hemiparkinsonian rats, distributed into the groups: SO (sham-operated), 6-hydroxydopamine (6-OHDA), and 6-OHDA (treated with SPF, 5 and 10 mg/kg, p.o., 15 days). Afterward, animals were subjected to behavioral tests and euthanized, and brain areas used for neurochemical and IHC assays. SPF partly reversed the changes in the apomorphine-induced rotations, open field and forced swim tests, and also the decrease in striatal dopamine and 3,4-dihydroxyphenylacetic acid contents seen in hemiparkinsonian rats. Furthermore, SPF reduced brain oxidative stress and increased striatal expressions of tyrosine hydroxylase and dopamine transporter and significantly reduced hippocampal inducible nitric oxide synthase, cyclooxygenase-2 and glial fibrillary acidic protein expressions. The data suggest that the protein fraction from S. platensis, through its brain anti-inflammatory and antioxidative actions, exerts neuroprotective effects that could benefit patients affected by neurodegenerative diseases, like Parkinson's disease. [ABSTRACT FROM AUTHOR]

Background. Diabetes is a metabolic disease linked to multiple comorbidities, such as low-grade inflammation. β-pinene, a monoterpene commonly found in aromatic plants, is endowed with anti-inflammatory effect and this fact lead us to investigate the possible hypoglycemic, hypolipidemic and anti-inflammatory effects of the monoterpene in the alloxan-induced diabetes experimental model. Methods. Male Wistar rats (200–250 g) were treated orally with β-pinene (25, 50, 100, and 200 mg/kg) or glibenclamide (5 mg/kg), for seven consecutive days. Diabetes was induced by alloxan (40 mg/kg) through the penile vein. On the seventh day of treatment, blood samples were collected for biochemical analysis. The anti-inflammatory effect of β-pinene was evaluated using the carrageenan-induced paw edema model, followed by the carrageenan-induced peritonitis. Results. The treatment with β-pinene decreased plasma glucose, triglyceride, VLDL, LDL, and HDL levels, when compared to those of the control group. In addition, the association β-pinene 10 mg/kg + glibenclamide 2 mg/kg significantly decreased blood glucose, total cholesterol, and triglyceride level. Finally, oral treatment with β-pinene reduced carrageenan-induced paw edema and leukocyte migration in the peritoneum. Taken together, our results indicate that β-pinene shows hypoglycemic and hypolipemic effects, which may involve some common mechanisms of glibenclamide. Besides, the monoterpene presented an anti-inflammatory action in diabetic rats that needs further investigation in order to clarify such effect and its correlation with the alterations observed in plasma parameters of β-pinene-treated diabetic rats. [ABSTRACT FROM AUTHOR]

Sesquiterpernes are natural compounds widely distributed in plants rich in essential oils; among these compounds, α -humulene and its isomers stand out for their multiple pharmacological properties and for their uses in the cosmetics, perfumery and food industries. The present study aimed to conduct a systematic review (SR) in order to identify the pharmacological and toxicological activities of α -humulene and its isomers. This SR was carried out in accordance with the PRISMA guidelines. The bibliographic search was performed using PubMed, Scopus and Web of Science databases. The inclusion criteria used were: original articles from preclinical and clinical studies that investigated the pharmacological activities and toxicological effects of α- humulene and its isomers, which were written in English, Portuguese and Spanish. The initial search resulted in 5165 articles, of which 46 were selected for final analysis. After grouping into categories by activity presented, 41% of the investigated articles reported that α-humulene and its isomers had antitumor activity, followed by anti-inflammatory and antimicrobial activities (20% for both), other pharmacological activities (15%) and potential toxic (2%). This SR is the first developed grouping studies on the pharmacological and toxicological activities of this group of compounds. In this perspective, it is concluded that α- humulene, as well as its isomers, have different pharmacological activities, listing them as an important precursor for new therapies. However, there is still a need for further toxicological investigation on these compounds, in order to ensure safety for their use. • Experimental studies with α-humulene and its isomers present relevant potential anti-tumor and cytotoxic action against cancer cells; • α-humulene and its isomers have been shown to be effective against a wide range of microorganisms and activating or inactivating several factors involved in the inflammatory process; • These compounds were characterized as having great gastroprotective, cicatrizing, analgesic and antioxidant potentials; [ABSTRACT FROM AUTHOR]

This study aimed to investigate, through in vivo and biochemical methodologies, the effect of trans,trans -farnesol (12.5, 25, 50 or 100 mg/kg, p.o.) acute administration, adopting different behavioral and neurochemical parameters associated with an acute induced-depression model in mice. The initial results showed that, the oral treatment with trans,trans -farnesol, at the dose of 100 mg/kg induced a possible antidepressant-like effect in animals subjected to forced swim test (FST) and reserpine-induced akinesia. In addition, it was observed that the compound in question has an effect size and properties similar to imipramine (prototype of tricyclic antidepressants), but devoid of proconvulsant adverse effect. In biochemical assays, the pretreatment with trans,trans -farnesol, at a dose of 100 mg/kg (p.o.), decreased the hippocampal concentration of thiobarbituric acid reactive substances (TBARS) and restored striatal levels of noradrenaline and serotonin in mice subjected to FST. Altogether, these results suggest that trans,trans -farnesol showed a significant antidepressant-like effect, which seems to be mediated by the antagonism of muscarinic cholinergic receptors, reduction of oxidative stress and the modulation of noradrenaline and serotonin content in the central nervous system. [Display omitted] • Trans,trans -farnesol presents a antidepressant-like effect. • The effects of Trans,trans -farnesol appear to be mediated, in part, by the antagonism of muscarinic cholinergic receptors. • Trans,trans -farnesol restored striatal levels of noradrenaline and serotonin. • Trans,trans -farnesol reduces hippocampal levels of thiobarbituric acid reactive substances (TBARS). [ABSTRACT FROM AUTHOR]

With the increase of neglected diseases such as leishmaniasis and Chagas disease, there was a need for the search for new therapeutic alternatives that reduce the harm caused by medicine available for treatment. Thus, this study was performed to investigate the antiparasitic activity of the essential oil from the fruits of Piper tuberculatum Jacq, against lines of Leishmania braziliensis (MHOM/CO/88/UA301), Leishmania infantum (MHOM/ES/92/BCN83) and Trypanosoma cruzi (LC-B5 clone). Before running protocols, an analysis of the chemical composition of essential oil was conducted, which presented monoterpenes and sesquiterpenes. As major constituents, β-pinene and α-pinene were identified. Regarding to antiparasitic activity, the essential oil had an EC50 values of 133.97 µg/mL and 143.59 µg/mL against variations promastigotes of L. infantum and L. braziliensis, respectively. As for trypanocidal activity, the oil showed EC50 value of 140.31 µg/mL against epimastigote form of T. cruzi. Moreover, it showed moderate cytotoxicity in fibroblasts with LC50 value of 204.71 µg/mL. The observed effect may be related to the presence of terpenes contained in the essential oil, since it has its antiparasitic activity proven in the literature. [ABSTRACT FROM AUTHOR]

This study aimed to investigate, through in vivo and in vitro methodologies, the effect of acute trans,trans- farnesol (12.5, 25, 50 or 100 mg/kg, p.o.) administration on behavioral and neurochemical parameters associated with pilocarpine-induced epileptic seizure (300 mg/kg, i.p.) in mice. The initial results showed that the compound in question presents no anxiolytic-like or myorelaxant effects, despite reducing locomotor activity in the animals at all doses tested. In addition, the lowest dose increased the latency to onset of the first epileptic seizure, and the time to death. In addition to decreasing the mortality percentage in mice submitted to the pilocarpine model. In this same model, pretreatment with the lowest dose of the compound decreased the hippocampal concentrations of thiobarbituric acid and nitrite, and partially restored striatal concentrations of noradrenaline, dopamine, and serotonin. Taken together, the results suggest that trans,trans -farnesol presents a central depressant effect which contributes to its antiepileptic action which, in turn, seems to be mediated by the antagonism of muscarinic cholinergic receptors, reduction of oxidative stress. and modulation of noradrenaline, dopamine and serotonin concentrations in the central nervous system. • Trans,trans -farnesol presents a protective effect on pilocarpine-induced seizures. • This substance is a possible antagonist of the M1 muscarinic receptors. • Trans,trans -farnesol increases dopamine and serotonin striatal levels. • Trans,trans -farnesol reduces hippocampal levels of TBARS and nitrite. [ABSTRACT FROM AUTHOR]

In the present study, we evaluated omega-3 polyunsaturated fatty acid (PUFA) (consisting of 20:5n-3 and 22:6n-3) properties on inflammation and nociception. Among the in vivo tests, writhing, formalin, and hot plate tests were conducted in mice, and carrageenan-induced paw edema, peritonitis, and Hargreaves tests were performed in rats. Following the carrageenan- induced edema, immunohistochemistry for tumor necrosis factor-α (TNF-α) was also carried out. We found that omega-3 PUFA treatment significantly decreased acetic acid-induced abdominal contortions as well as the first and second phases of the formalin test, which were reversed by naloxone. The carrageenan-induced rat paw edema was significantly reduced, along with neutrophil migration to the peritoneal cavity in the omega-3 PUFA treatment. In addition, there was a decrease in TNF-α immunostained cells in the inflamed paw with the omega-3 treatment compared with no omega-3. Withdrawal threshold in response to the thermal stimulation was significantly increased by the omega-3 treatment in the Hargreaves and hot plate tests. The in vitro studies (myeloperoxidase, lactate dehydrogenase, MTT cell viability and lipid peroxidation assays) were performed in human neutrophils. These studies showed that omega-3 treatment significantly decreased myeloperoxidase release, presented no cytotoxicity, and did not alter lipid peroxidatlon. Our study suggests that omega-3 PUFA anti-inflammatory and antinociceptive actions may involve inhibition of cyclooxygenases and microglial activation, leading to a reduced release of proinflammatory cytokines such as TNF-α, among other factors. The omega-3 PUFAs are potential candidates used alone or in combination with conventional nonsteroidal anti- inflammatory drugs, for the treatment of diseases where inflammation plays an important role. [ABSTRACT FROM AUTHOR]

This research evaluated the anxiolytic and antidepressant-like effects of a hydroethanolic extract from the leaves of Annona coriacea (EHFAC) and caffeic acid (CA). Mice were intraperitoneally treated with saline, EHFAC (1, 10, 20 mg/kg) or CA (0.15 mg/kg) and subject to the elevated plus-maze, open field, rota-rod, forced swimming and reserpine-induced akinesia tests. Pro-convulsant and anticholinergic effects were also evaluated. EHFAC presented anxiolytic-like effect on the elevated plus-maze, which was partially reversed by flumazenil. A similar effect was observed with CA. In the forced swimming test, EHFAC and CA reduced the immobility time of mice; such effect was potentiated when EHFAC or CA were associated with imipramine, bupropion and fluoxetine. The antidepressant-like effect was reinforced as EHFAC partially reversed the reserpine-induced akinesia. In addition, a pre-treatment with EHFAC and CA did not decrease the latency to 1st seizure of animals that received a sub-convulsive dose of PTZ, nor reduced the intensity of oxotremorine-induced tremors. Taken together, the results indicate that EHFAC and CA have anxiolytic and antidepressant-like effects, which involve important neurotransmitter systems, such as GABAergic and monoaminergic ones, being devoid of side effects, commonly associated with classical psychotropic drugs. • Anxiolytic and antidepressant-like effects are reported. • Possible involvement of the GABAergic and monoaminergic systems. • Devoid of side effects commonly associated with classical psychotropic drugs. [ABSTRACT FROM AUTHOR]

Chronic pain management has several adverse effects and research looking for new and effective pain management drugs posing lower undesirable effects is necessary. Given the above, the pharmacological investigation of medicinal plants significantly contributes to the dissemination of plant-derived therapeutics. The aim of this study was to evaluate the antinociceptive activity of the Psidium brownianum Mart ex DC. leaf essential oil (PBEO) and the participation of the opioid pathway in this effect in mice. Swiss Mus musculus male mice were tested using acute nociception models (acetic acid induced abdominal contortions, formalin, capsaicin and hot plate tests). The possible myorelaxant action of the PBEO was tested using the rotarod test. The essential oil reduced animal nociception in chemical and heat models, with this action being devoid of a myorelaxant effect. Naloxone (2 mg/kg, intraperitoneally – i.p.) partially antagonized the PBEO activity, possibly acting via opioid receptors. The results obtained provide evidence that the traditional Psidium brownianum use may be effective for pain treatment. [ABSTRACT FROM AUTHOR]

The aim of this study was to characterize the central effects of the Hyptis martiusii leaf essential oil (OEHM) and 1,8-cineole (eucalyptol) using behavioral animal models. Gas chromatography coupled to mass spectrometry (GC/MS) was used to characterize the chemical compounds present in the OEHM. For the behavioral tests, female Swiss mice treated with the OEHM (25, 50, 100 and 200 mg/kg, i.p.) and 1,8-cineole (50 mg/kg, i.p.) were used and subjected to the following tests: open field, elevated cross maze, rotarod, sodium pentobarbital- or ethyl ether-induced sleep time, pentylenetetrazol-induced convulsions, haloperidol-induced catalepsy, and ketamine-induced hyperkinesia. GC/MS analysis identified 20 constituents with the majority of them being monoterpenes and sesquiterpenes, with eucalyptol (1,8-cineol), the major sample compound (25.93%), standing out. The results showed the OEHM (25, 50 100 and 200 mg/kg, i.p.) and its major compound (50 mg/kg, i.p.) reduced animal motility in the open field test, increased pentobarbital- and ethyl ether-induced sleep time, as well as death latency in the pentylenetetrazole-induced convulsion model. However, the tested compounds were devoid of anxiolytic-like and myorelaxant activity. In addition, the OEHM (100 and 200 mg/kg, i.p.) and 1,8-cineole (50 mg/kg, i.p.) potentiated haloperidol-induced catalepsy and reduced ketamine-induced hyperkinesia. Taken together, the results suggest the OEHM has important hypnotic-sedative and antipsychotic-like effects, which appear to be due to the monoterpene 1,8-cineole, the major compound identified in the essential oil. • Hyptis martiusii essential oil presented no signs of toxicity/mortality. • The essential oil presented important effects on the CNS. • Such effects seems to depend upon the presence of 1,8-cineole in the essential oil. [ABSTRACT FROM AUTHOR]