RESUMO
Psychotria is a complex genus whose neotropical species are known by the presence of glucosidic monoterpene indole alkaloids. These compounds are able to display a large range of effects on the central nervous system, such as anxiolytic, antidepressant, analgesic, and impairment of learning and memory acquisition. The aims of this study were to investigate the effects displayed by strictosidinic acid, isolated from Psychotria myriantha Mull. Arg. (Rubiaceae) leaves, on monoamine levels in rat hippocampus and on monoamine oxidase activity. A significance (p<0.01) of 83.5% reduction in 5-HT levels was observed after intra-hippocampal injection (20 µg/µl). After treatment by intraperitoneal route (10 mg/kg), a 63.4% reduction in 5-HT levels and a 67.4% reduction in DOPAC values were observed. The results indicate that strictosidinic acid seems to act on 5-HT system in rat hippocampus, possibly inhibiting precursor enzymes of 5-HT biosynthesis. The decrease verified in DOPAC levels suggests a role of strictosidinic acid in the dopaminergic transmission, probably due to an inhibition of monoamine oxidase activity, confirmed by the enzymatic assay, which demonstrated an inhibitory effect on MAO A in rat brain mitochondria.
Assuntos
Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Carbolinas/farmacologia , Glicosídeos/farmacologia , Hipocampo/metabolismo , Monoaminoxidase/metabolismo , Extratos Vegetais/farmacologia , Psychotria/química , Serotonina/metabolismo , Animais , Carbolinas/administração & dosagem , Carbolinas/isolamento & purificação , Glicosídeos/administração & dosagem , Glicosídeos/isolamento & purificação , Masculino , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Inibidores da Monoaminoxidase/administração & dosagem , Inibidores da Monoaminoxidase/isolamento & purificação , Inibidores da Monoaminoxidase/farmacologia , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química , Folhas de Planta , Ratos , Ratos Wistar , Serotonina/biossíntese , Antagonistas da Serotonina/administração & dosagem , Antagonistas da Serotonina/isolamento & purificação , Antagonistas da Serotonina/farmacologiaRESUMO
Strictosidinic acid 10mg/kg, isolated from Psychotria myriantha leaves, were administered intraperitoneally to Wistar male rats (n=5-6). After 60 minutes, striatum was dissected, homogenized and injected onto HPLC-ED chromatographic system. It was observed a 28.7% reduction in the 5-HT levels followed up by an increase of 5-HIAA levels (29.4%). Furthermore there was a decrease of 8.0% in DA levels and an increase in the levels of metabolites DOPAC (21.5%) and HVA (52.5%). The results indicate that strictosidinic acid has a promising effect in the central nervous system, justifying more studies about the central actions of Psychotria compounds.
Assuntos
Carbolinas/farmacologia , Corpo Estriado/efeitos dos fármacos , Dopamina/metabolismo , Glicosídeos/farmacologia , Neurotransmissores/farmacologia , Extratos Vegetais/farmacologia , Rubiaceae/química , Serotonina/metabolismo , Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Animais , Carbolinas/isolamento & purificação , Corpo Estriado/metabolismo , Glicosídeos/isolamento & purificação , Ácido Homovanílico/metabolismo , Injeções Intraperitoneais , Masculino , Neurotransmissores/administração & dosagem , Neurotransmissores/isolamento & purificação , Fenilacetatos/metabolismo , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química , Folhas de Planta , Ratos , Ratos Wistar , Serotonina/análogos & derivadosRESUMO
Mikania laevigata Schultz Bip. ex Baker, M. involucrata Hook. et Arn. and M. hirsutissima DC. (Asteraceae), commonly occurring in the southern Brazilian State of Rio Grande do Sul, were submitted to biological tests to evaluate their potential antiinflammatory activity. Decoctions from the leaves and stems were analysed by the induced rat paw oedema and pleurisy models. The animals were treated orally with different decoction doses. In the induced rat paw oedema test, the animals treated with leaf decoctions from M. laevigata (200 mg/ kg) and M. involucrata (50 mg/ kg) presented an oedema inhibition of 81.56% and 81.67%, respectively, 3 h after the administration of the phlogistic agent. Leaf decoctions from M. hirsutissima (400 mg/ kg) did not show such an activity. Stem decoctions displayed lower antiinflammatory activity when compared with the same doses and response time of the leaf decoctions for all analysed species. In the pleurisy assay, leaf decoctions from M. laevigata (400 mg/ kg) and M. involucrata (200 mg/ kg) inhibited leukocyte migration to the pleural exudate by 28.26% and 54.35%, respectively.