The anti-inflammatory and antinociceptive effects of proteins extracted from Acacia farnesiana seeds / Efeito antiiflamatório e antinociceptivo de proteínas extraídas de sementes de Acacia farnesiana

ABSTRACT Seeds of Acacia farnesiana are commonly sold in the local markets of northeastern Brazil as a therapeutic agent. The present work aimed to evaluate the anti-inflammatory and analgesic activities of proteins obtained from A. farnesiana seeds. Five different protein fractions (albumin, globulin, prolamin, acidic and basic glutelins) were obtained and investigated for the protein pattern, the presence of hemagglutinating and proteolytic activities. The globulin fraction (GLB) was also evaluated for anti-inflammatory and analgesic activities. Globulins reduced the paw edema induced by carrageenan in a dose-dependent manner, which was accompanied by a reduction of myeloperoxidase activity (p < 0.05). Additionally, GLB reduced the neutrophil peritoneal migration induced by carrageenan. However, GLB was not able to inhibit the edema triggered by dextran. Pre-treatment with globulins reduced the abdominal constrictions induced by acetic acid as well as the paw licking time induced by formalin (69.1% at first phase). However, it did not produce a significant antinociceptive effect in the hot plate test (55-56 °C). Treating the GLB with heat (at 100 °C for 30 min) abolished its anti-edematogenic and hemagglutinating activities. Our results showed that seeds from A. farnesiana are a source of proteins with anti-inflammatory and analgesic properties.

RESUMO Sementes de Acacia farnesiana são comumente vendidas em feiras locais no nordeste do Brasil como agente terapêutico. O presente trabalho objetivou avaliar as atividades antiinflamatória e antinociceptiva de proteínas obtidas de sementes de A. farnesiana. Cinco frações protéicas distintas (albuminas, globulinas, prolaminas, glutelinas ácidas e básicas) foram obtidas e investigadas quanto o perfil de proteínas, presença de atividade hemaglutinante e proteolítica. A fração globulina (GLB) também foi avaliada quanto a presença de atividade antiinflamatória e analgésica. Globulinas reduziram o edema de pata induzido por carragenina de modo dependente da dose que foi acompanhada da redução da atividade da mieloperoxidase (p < 0,05). Em adição, GLB reduziu a migração de neutrófilos para cavidade peritoneal induzida por carragenina. Entretanto, GLB não foi capaz de inibir o edema induzido por dextrana. O pré-tratamento com globulinas reduziu as contorções abdominais induzidas por ácido acético, bem como o tempo de lambedura da pata induzida por formalina (69.1% na primeira fase). Por outro lado, GLB não produziu um efeito antinociceptivo significante no teste de placa quente (55-56 °C). O pré-tratamento de GLB com calor (100 °C por 30 min) aboliu sua atividade anti-edematogênica e hemaglutinante. Nossos resultados mostraram que sementes de A. farnesiana são fonte de proteínas com propriedades antiinflamatórias e analgésicas.

The hydrogen sulfide donor, Lawesson's reagent, prevents alendronate-induced gastric damage in rats

Our objective was to investigate the protective effect of Lawesson's reagent, an H2S donor, against alendronate (ALD)-induced gastric damage in rats. Rats were pretreated with saline or Lawesson's reagent (3, 9, or 27 µmol/kg, po) once daily for 4 days. After 30 min, gastric damage was induced by ALD (30 mg/kg) administration by gavage. On the last day of treatment, the animals were killed 4 h after ALD administration. Gastric lesions were measured using a computer planimetry program, and gastric corpus pieces were assayed for malondialdehyde (MDA), glutathione (GSH), proinflammatory cytokines [tumor necrosis factor (TNF)-α and interleukin (IL)-1β], and myeloperoxidase (MPO). Other groups were pretreated with glibenclamide (5 mg/kg, ip) or with glibenclamide (5 mg/kg, ip)+diazoxide (3 mg/kg, ip). After 1 h, 27 µmol/kg Lawesson's reagent was administered. After 30 min, 30 mg/kg ALD was administered. ALD caused gastric damage (63.35±9.8 mm2); increased levels of TNF-α, IL-1β, and MDA (2311±302.3 pg/mL, 901.9±106.2 pg/mL, 121.1±4.3 nmol/g, respectively); increased MPO activity (26.1±3.8 U/mg); and reduced GSH levels (180.3±21.9 µg/g). ALD also increased cystathionine-γ-lyase immunoreactivity in the gastric mucosa. Pretreatment with Lawesson's reagent (27 µmol/kg) attenuated ALD-mediated gastric damage (15.77±5.3 mm2); reduced TNF-α, IL-1β, and MDA formation (1502±150.2 pg/mL, 632.3±43.4 pg/mL, 78.4±7.6 nmol/g, respectively); lowered MPO activity (11.7±2.8 U/mg); and increased the level of GSH in the gastric tissue (397.9±40.2 µg/g). Glibenclamide alone reversed the gastric protective effect of Lawesson's reagent. However, glibenclamide plus diazoxide did not alter the effects of Lawesson's reagent. Our results suggest that Lawesson's reagent plays a protective role against ALD-induced gastric damage through mechanisms that depend at least in part on activation of ATP-sensitive potassium (KATP) channels.