RESUMO
The action of an Agaricus blazei aqueous extract pretreatment on paracetamol injury in rats was examined not only in terms of the classical indicators (e.g., levels of hepatic enzymes in the plasma) but also in terms of functional and metabolic parameters (e.g., gluconeogenesis). Considering solely the classical indicators for tissue damage, the results can be regarded as an indication that the A. blazei extract is able to provide a reasonable degree of protection against the paracetamol injury in both the hepatic and brain tissues. The A. blazei pretreatment largely prevented the increased levels of hepatic enzymes in the plasma (ASP, ALT, LDH, and ALP) and practically normalized the TBARS levels in both liver and brain tissues. With respect to the functional and metabolic parameters of the liver, however, the extract provided little or no protection. This includes morphological signs of inflammation and the especially important functional parameter gluconeogenesis, which was impaired by paracetamol. Considering these results and the long list of extracts and substances that are said to have hepatoprotective effects, it would be useful to incorporate evaluations of functional parameters into the experimental protocols of studies aiming to attribute or refute effective hepatoprotective actions to natural products.
Assuntos
Acetaminofen/efeitos adversos , Agaricus/química , Encefalopatias/induzido quimicamente , Encefalopatias/tratamento farmacológico , Doença Hepática Induzida por Substâncias e Drogas/tratamento farmacológico , Misturas Complexas/uso terapêutico , Acetaminofen/administração & dosagem , Acetaminofen/sangue , Administração Oral , Alanina/metabolismo , Animais , Antioxidantes/metabolismo , Biomarcadores/sangue , Encéfalo/efeitos dos fármacos , Encéfalo/enzimologia , Encéfalo/patologia , Encefalopatias/sangue , Encefalopatias/patologia , Doença Hepática Induzida por Substâncias e Drogas/sangue , Doença Hepática Induzida por Substâncias e Drogas/patologia , Misturas Complexas/farmacologia , Ensaios Enzimáticos , Glucose/metabolismo , Glicogênio/metabolismo , Ácido Láctico/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/enzimologia , Fígado/patologia , Masculino , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Wistar , Fatores de TempoRESUMO
The effects of a hydroalcoholic extract of Agaricus brasiliensis (A. blazei) on functional parameters in the perfused rat liver were examined with emphasis on its content of nucleotides and nucleosides. Several nucleosides and nucleotides were identified in the A. brasiliensis extract, which was active on several liver functions. A significant part of the effects is the result of the purinergic action of nucleosides and nucleotides: pressure increment, glycogenolysis stimulation, transient inhibition of oxygen consumption, and redox state changes. Other phenomena such as the stimulation of gluconeogenesis, ureogenesis, and oxygen consumption are more likely consequences of the metabolic transformation of substrates contained within the extract, especially amino acids. It seems apparent that consumption of A. brasiliensis represents not only the ingestion of metabolic precursors but also the ingestion of substances that, even at low concentrations, can exert important signaling functions in the liver as well as in the organism as a whole.