The antinociceptive and anti-inflammatory activity of caulerpin was investigated. This bisindole alkaloid was isolated from the lipoid extract of Caulerpa racemosa and its structure was identified by spectroscopic methods, including IR and NMR techniques. The pharmacological assays used were the writhing and the hot plate tests, the formalin-induced pain, the capsaicin-induced ear edema and the carrageenan-induced peritonitis. Caulerpin was given orally at a concentration of 100 μmol/kg. In the abdominal constriction test caulerpin showed reduction in the acetic acid-induced nociception at 0.0945 μmol (0.0103–1.0984) and for dypirone it was 0.0426 μmol (0.0092–0.1972). In the hot plate test in vivo the inhibition of nociception by caulerpin (100 μmol/kg, p.o.) was also favorable. This result suggests that this compound exhibits a central activity, without changing the motor activity (seen in the rotarod test). Caulerpin (100 μmol/kg, p.o.) reduced the formalin effects in both phases by 35.4% and 45.6%, respectively. The possible anti-inflammatory activity observed in the second phase in the formalin test of caulerpin (100 μmol/kg, p.o.) was confirmed on the capsaicin-induced ear edema model, where an inhibition of 55.8% was presented. Indeed, it was also observed in the carrageenan-induced peritonitis that caulerpin (100 μmol/kg, p.o.) exhibited anti-inflammatory activity, reducing significantly the number of recruit cells by 48.3%. Pharmacological studies are continuing in order to characterize the mechanism(s) responsible for the antinociceptive and anti-inflammatory actions and also to identify other active principles present in Caulerpa racemosa.

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We investigated the antinociceptive and anti-inflammatory activities of the crude ethanolic extract (CEE), its fractions, and the flavonoid isorhamnetin from Aspidosperma tomentosum using models of nociception and inflammation in mice. In the writhing test, the CEE and its fractions (except for soluble phase, CHCl3 100% and EtAcO 100%) at 100 mg/kg p.o. induced antinociceptive activity. Isorhamnetin (100 μmol/kg, p.o.) was also active. In the hot plate test, only the treatment with the fractions Hex : CHCl3 50%, CHCl3 100%, and CHCl3 : MeOH 5% (100 mg/kg, p.o.) increased the latency time, reversed by the opioid antagonist naloxone. Fractions that were active in the hot plate test did not show catalepsy condition. It was observed that CEE, all fractions, and isorhamnetin reduced the formalin effects in the neurogenic phase. In the inflammatory phase, only CEE, isorhamnetin, and CHCl3 100% and CHCl3 : MeOH 5% fractions were active. CEE and all fractions, except for CHCl3 : MeOH 10% fraction, isorhamnetin, and soluble fraction were able to produce an antioedematogenic activity in the ear capsaicin-induced edema test. In the thioglycolate-induced peritonitis, only EtAcO 100% fraction was not active. The results demonstrate that A. tomentosum has antinociceptive and anti-inflammatory activities in animal models.

Erythrina mulungu Mart. ex Benth., Fabaceae, popularly known as mulungu, is used for the treatment of insomnia and disorders of the central nervous system. This study examined the antinociceptive effects of the hydroalcoholic extracts (HAE), the ethyl acetate and chloroformic fractions from E. mulungu in four experimental models of nociception using laboratory mice. The extracts and fractions were administered orally to mice at doses of 100 mg/kg. Inhibition of abdominal contractions were observed for all the extracts and fractions tested, as compared to controls. All extracts and fractions from E. mulungu reduced the nociception activity produced by formalin in the 2 nd phase. In the hot plate test no significant effect was observed for any extract or fraction. In the peritonitis test induced by Zymosan, all of the tested extracts and the chloroformic fraction, except for the ethyl acetate phase, reduced cell migration of the peritoneal cavity. We concluded that E. mulungu shows antinociceptive effects, which are independent of the opioid system.