ABSTRACT
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.
Subject(s)
3,4-Dihydroxyphenylacetic Acid/metabolism , Carbolines/pharmacology , Glycosides/pharmacology , Hippocampus/metabolism , Monoamine Oxidase/metabolism , Plant Extracts/pharmacology , Psychotria/chemistry , Serotonin/metabolism , Animals , Carbolines/administration & dosage , Carbolines/isolation & purification , Glycosides/administration & dosage , Glycosides/isolation & purification , Male , Mitochondria/drug effects , Mitochondria/metabolism , Monoamine Oxidase Inhibitors/administration & dosage , Monoamine Oxidase Inhibitors/isolation & purification , Monoamine Oxidase Inhibitors/pharmacology , Plant Extracts/administration & dosage , Plant Extracts/chemistry , Plant Leaves , Rats , Rats, Wistar , Serotonin/biosynthesis , Serotonin Antagonists/administration & dosage , Serotonin Antagonists/isolation & purification , Serotonin Antagonists/pharmacologyABSTRACT
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.
Subject(s)
Carbolines/pharmacology , Corpus Striatum/drug effects , Dopamine/metabolism , Glycosides/pharmacology , Neurotransmitter Agents/pharmacology , Plant Extracts/pharmacology , Rubiaceae/chemistry , Serotonin/metabolism , 3,4-Dihydroxyphenylacetic Acid/metabolism , Animals , Carbolines/isolation & purification , Corpus Striatum/metabolism , Glycosides/isolation & purification , Homovanillic Acid/metabolism , Injections, Intraperitoneal , Male , Neurotransmitter Agents/administration & dosage , Neurotransmitter Agents/isolation & purification , Phenylacetates/metabolism , Plant Extracts/administration & dosage , Plant Extracts/chemistry , Plant Leaves , Rats , Rats, Wistar , Serotonin/analogs & derivativesABSTRACT
Os radicais livres estão envolvidos em um grande número de enfermidades do ser humano.O cérebro tem níveis baixos de enzimas antioxidantes e um conteúdo lípidico elevado, tornando-se muito susceptível ao ataque de espécies reativas de oxigênio.Neste trabalho avaliou-se a lipoperoxidação em hipocampo e a atividade da enzima catalase em estriado e hipocampo de ratos tratados com o fungicida maneb (30 mg/kg) e o herbicida paraquat (10 mg/kg).Não houve alteração na lipoperoxidação nem na atividade enzimática no hipocampo dos animais tratados com ambos os praguicidas, porém foi observada uma inibição da catalase no estriado dos ratos tratados com maneb e com paraquat.Com estes resultados pode-se sugerir, de forma preliminar, uma ação tóxica maior sobre centros dopaminérgicos.Estudos sobre a toxicidade destes compostos são essenciais na compreensão do papel destes praguicidas e dos radicais livres na etiologia das doenças
Subject(s)
Animals , Male , Rats , Catalase/adverse effects , Maneb/analysis , Maneb/adverse effects , Maneb/toxicity , Paraquat/analysis , Paraquat/adverse effects , Paraquat/toxicity , Rats, WistarABSTRACT
The standardized extract of Ginkgo biloba (EGb 761) has been widely employed for its significant benefit in neurodegenerative disorders. Although antioxidative actions have been attributed to this extract, the mechanisms of the multiple principles involved in this pharmacological activity are not completely established. Parkinson's and Alzheimer's diseases are frequently associated with oxidative stress and defects in the cellular protective mechanisms. In this study, the lipid peroxidation (LPO) and the activity of the antioxidant enzymes, catalase (CAT) and superoxide dismutase (SOD) were evaluated in the hippocampus, striatum and substantia nigra (SN) of rats treated with EGb 761. An increase in the CAT and SOD activities in the hippocampus, striatum and SN, and a decrease of the LPO in the hippocampus were observed. These data are additional to the antioxidant properties of EGb 761 reported in the literature and indicate a possible role for the extract in the treatment of diseases involving free radicals and oxidative damage.