title: Antinociceptive activity of sulfated carbohydrates from the red algae Bryothamnion seaforthii (Turner) Kütz. and B. triquetrum (S.G. Gmel.) M. Howe.
abstract: We report the antinociceptive activity, determined by the writhing, formalin and hot-plate tests in mice, of crude (F0/60), lectin and carbohydrate fractions isolated by ammonium sulfate precipitation (0 to 60%) from Bryothamnion seaforthii and B. triquetrum, species of red algae. Not only fraction F0/60 but also lectins from both species significantly inhibited acetic acid-induced abdominal contractions after intraperitoneal or oral administrations. In the formalin test, lectins (1 and 5 mg/kg, ip, and 5 to 20 mg/kg, po) inhibited the 1st and 2nd phases (5 and 20 min, respectively), but the effect occurred predominantly on the 2nd phase. The effects of the lectins were totally or partially reversed by naloxone (2 mg/kg, sc) in the 1st and 2nd phases, respectively. Experiments performed with lectins in the absence and presence of avidin (1 mg/kg, ip) and D-mannose (1 mg/kg, ip) showed that avidin did not interfere with the effect of B. seaforthii lectin but partially reversed the effect of B. triquetrum lectin. D-Mannose completely reversed the effects of both species. F0/60 fractions from both algae significantly increased the latency time in response to thermal stimuli, and naloxone reversed antinociception, indicating the involvement of the opioid system in both the peripheral and central effects of the fractions. In the writhing test, the carbohydrate fractions were the most active, inhibiting the contractions by 71 and 79% (B. triquetrum) and by 46 and 69% (B. seaforthii) at doses of 1 and 5 mg/kg, ip, respectively. Sulfated carbohydrate fractions of B. seaforthii and B. triquetrum, containing only about 5% protein as contaminants, are probably responsible for the antinociceptive effects of these red algae.
authors.affiliation: Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil. osorio@roadnet.com.br
authors.forename: G S B
authors.initials: GS
authors.lastname: Viana
authors.forename: A L P
authors.initials: AL
authors.lastname: Freitas
authors.forename: M M L
authors.initials: MM
authors.lastname: Lima
authors.forename: L A P
authors.initials: LA
authors.lastname: Vieira
authors.forename: M C H
authors.initials: MC
authors.lastname: Andrade
authors.forename: N M B
authors.initials: NM
authors.lastname: Benevides
mesh_terms: D000700:Analgesics / Q000032:analysis / Q000494:pharmacology*; D000818:Animals; D002241:Carbohydrates / Q000032:analysis / Q000494:pharmacology*; D002417:Cattle; D005260:Female; D037102:Lectins / Q000032:analysis / Q000494:pharmacology*; D008297:Male; D051379:Mice; D010936:Plant Extracts / Q000494:pharmacology; D037121:Plant Lectins; D010946:Plants, Medicinal / Q000737:chemistry*; D000461:Rhodophyta / Q000737:chemistry*; D013431:Sulfates
chemical_list: D000700:Analgesics; D002241:Carbohydrates; D037102:Lectins; D010936:Plant Extracts; D037121:Plant Lectins; D013431:Sulfates