Acute toxicity, antinociceptive, and anti-inflammatory activities of the orally administered crotamine in mice.

Crotamine is a polypeptide toxin isolated from rattlesnake venom. Although several studies have been developed identifying many biological effects of isolated crotamine, none of them evaluated its acute toxicity, antinociceptive, and anti-inflammatory activities through oral administration. All in vivo experiments from this study were performed in mice. The up-and-down procedure and hippocratic screening were carried out to evaluate possible pharmacological and toxic effects. Antinociceptive and anti-inflammatory activities of this toxin were evaluated using acetic acid-induced abdominal writhing, formalin-induced pain assays, croton oil-induced ear edema, and carrageenan-induced pleurisy. Crotamine did not cause lethality or signs of intoxication up to the maximum dose tested (10.88 mg/kg). The number of contortions was reduced significantly by 34, 57, and 74% at the oral doses of 0.08, 0.16, and 0.32 mg/kg, respectively. At the dose of 0.16 mg/kg, crotamine decreases pain time-reactivity at neurogenic phase by 45% and at inflammatory phase by 60%. Also, crotamine elicited antiedematogenic activity through the attenuation of the croton oil-induced ear edema by 77%. In the carrageenan-induced pleurisy, the leukocyte, neutrophil, and mononuclear cell migration to the lesion site were reduced by 52%, 46%, and 59%, respectively. Altogether, crotamine demonstrated in vivo antinociceptive and anti-inflammatory effect through acute oral administration, generating an anti-migratory mechanism of action at non-toxic doses.

Involvement of monoaminergic systems in the antidepressant-like properties of Lafoensia pacari A. St. Hil.

ETHNOPHARMACOLOGICAL RELEVANCE: Lafoensia pacari A. St.-Hil. (Lythraceae), known popularly as "pacari" or "mangaba-brava" is popularly used in the state of Goiás, Brazil. The stem bark or leaves are used to treat cancer, gastric disorders, inflammation and as a tonic to treat loss of enthusiasm. AIM OF THE STUDY: Previous results suggest that the ethanol:water 7:3 extract of the stem bark of L. pacari (PEx) has antidepressant-like activity in male mice. Our aim was to perform the PEx׳s bioguided fractionation and evaluate the monoaminergic system involvement in the antidepressant effect as well as progress in the study of L. pacari mechanism of action. MATERIAL AND METHODS: Mice (30-35g) orally treated (24, 5 and 1h) with PEx (100, 300 or 1000mg/kg), chloroform (ChloF-70mg/kg), ethyl acetate (180mg/kg), n-butanol (370mg/kg) and aqueous (1g/kg) fractions were submitted to the forced swimming test. To assess the mechanism of action, different groups of mice were pretreated with p-chlorophenylalanine (PCPA-100mg/kg, 4 days, i.p.) and alpha-methyl-p-tyrosine (AMPT-100mg/kg, 4h, i.p.) to assess the involvement of serotoninergic and catecholaminergic systems in the ChloF effects, respectively. A putative in vitro inhibition of monoamine oxidase (MAO) activity as well as the ex vivo hippocampal brain-derived neurotrophic factor (BDNF) quantification were carried out. Phytochemical screening, spectroscopy and chromatography analysis were used for identification of compounds present in ChloF. RESULTS AND DISCUSSION: After the fractionation, the ChloF 70mg/kg was the most active fraction, reducing the immobility time by 22%. Pre-treatments with both PCPA and AMPT abolished the ChloF effects, suggesting that ChloF antidepressant-like effect is dependent on serotonergic and catecholaminergic systems. ChloF did not inhibited MAO-A or MAO-B activity, excluding this as possible mechanism of action. ChloF augmented hippocampal BDNF level, which could be accounted for its antidepressant-like effect. Phytochemical screening showed the presence of saponins, tannins, steroids and triterpene in the PEx, and the presence of triterpene and steroids in ChloF. The spectroscopy and chromatography analysis identified lupeol, ß-sitosterol and stigmasterol in ChloF. CONCLUSION: ChloF is the fraction that better retained the crude extract active constituents. ChloF presents antidepressant-like effect that involves both serotonergic and catecholaminergic systems without inhibiting MAO enzymatic activity; this fraction also increases the hippocampal BDNF levels.

Antinociceptive and antiinflammatory activities of grandisin extracted from Virola surinamensis.

The antinociceptive and antiinflammatory properties of the neolignan, grandisin, isolated from Virola surinamensis (Myristicaceae) were investigated. Grandisin (GRA) is present in several plant species from Brazil used in popular medicine for the treatment of disorders such as colic, inflammation, rheumatism, dyspepsia and liver dysfunction. These studies demonstrated that GRA is able to inhibit the acetic acid-induced writhing in mice dose-dependently, and that this effect is not caused by motor incoordination or sedation due to depressant effect in the CNS. Through the formalin test the antiinflammatory activity of GRA was characterized, this substance reduced the time licking the paw by 60.5% (only in the second phase (inflammatory pain). This activity was also verified by the oil-induced ear oedema test, where GRA 10.0 mg/kg reduced the oedema by 36.4%. The results suggest that GRA has antinociceptive effects arising from antiinflammatory activity.