RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: The leaves of Syzygium cumini (L.) or Skeels (Myrtaceae) are widely used in Brazilian folk medicine to treat diabetes. AIM OF THE STUDY: The present study evaluated the functional capacity, biochemical parameters, oxidative stress and DNA damage from eight weeks of intervention with a crude hydroalcoholic extract of S. cumini leaves (EBH) and continuous aerobic training (TAC) in diabetic (D) rats. MATERIALS AND METHODS: A hydroalcoholic (50%) extract was prepared by ultrasound and phytochemical parameters (total phenols, total tannins and myricetin content) were analyzed. Thirty-seven male Wistar rats were divided into five groups: normoglycemic controls (CONT), diabetic controls (D-CONT), diabetics treated with extract (D+EBH), trained diabetic (D+TAC) and diabetics treated with extract and trained (D+EBH+TAC). Functional capacity was assessed with a maximum exercise capacity test; biochemical parameters with enzymatic kits; oxidative stress by superoxide dismutase (SOD), catalase (CAT), thiobarbituric acid reactive substances (TBARS) and oxidized dichlorofluorescein (DCF), and the DNA damage by the comet assay. RESULTS: The D+TAC and D+EBH+TAC groups showed better functional capacity at the end of interventions. The D+EBH group showed glucose and triglyceride reduction, lowest DNA damage index in the blood, liver, kidney, heart, lung and gastrocnemius muscle, improved SOD levels in the liver, kidney and lung, improved CAT levels in the kidney and lower lipid peroxidation in all tissues studied, compared to the D-CONT group. The exercise (D+TAC) was effective in reducing triglycerides, improving SOD levels in the lung, reducing lipid peroxidation in all tissues studied and reducing the DCF oxidation in the kidney, in addition to protecting against DNA damage in the blood and heart. However, the additive effect of the intervention protocols when combined (EBH+TAC) was observed only in improving the gastrocnemius SOD levels. The phytochemical analyses showed a high content of phenols and the presence of myricetin glycosides. CONCLUSION: The findings in this study suggest a crude hydroalcoholic extract of S. cumini leaves has potential hypoglycemic, hypolipidemic and protective properties acting against oxidative stress and against DNA damage, probably due to its phenols and myricetin glycoside content and the antioxidant properties of these constituents. Moreover, exercise was suggested to have beneficial effects on diabetes, improving functional capacity, ameliorating blood triglyceride control and decreasing lipid peroxidation, but with no effects on ameliorating blood glucose levels. The association of intervention protocols presented an additive effect on the antioxidant SOD activity in the muscle cells of diabetic rats.
Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Myrtaceae/química , Condicionamento Físico Animal/fisiologia , Extratos Vegetais/farmacologia , Folhas de Planta/química , Syzygium/química , Animais , Antioxidantes/metabolismo , Brasil , Catalase/metabolismo , Dano ao DNA/efeitos dos fármacos , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/metabolismo , Dieta Hiperlipídica/efeitos adversos , Hipoglicemiantes/química , Hipoglicemiantes/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Medicina Tradicional/métodos , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/química , Ratos , Ratos Wistar , Estreptozocina/farmacologia , Superóxido Dismutase/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
Piper gaudichaudianum Kunth is used in popular medicine as anti-inflamatory and against liver disorders. One of the most studied components of the plant is the essential oil for which chemical analysis revealed (E)-nerolidol as major compound. Recently, we have shown that P. gaudichaudianum essential oil possesses strong cytotoxic effects in mammalian V79 cells. The aim of this study was to analyze the cytotoxicity and mutagenicity of P. gaudichaudianum essential oil and nerolidol using Saccharomyces cerevisiae as model study. Treatment of the XV185-14c and N123 strains with essential oil and nerolidol led to cytotoxicity but did not induce mutagenicity. Our results revealed an important role of base excision repair (BER) as the ntg1, ntg2, apn1 and apn2 mutants showed pronounced sensitivity to essential oil and nerolidol. In the absence of superoxide dismutase (in sod1Δ mutant strain) sensitivity to the essential oil and nerolidol increased indicating that this oil and nerolidol are generating reactive oxygen species (ROS). The ROS production was confirmed by DCF-DA probing assay in Sod-deficient strains. From this, we conclude that the observed cytotoxicity to P. gaudichaudianum essential oil and nerolidol is mainly related to ROS and DNA single strand breaks generated by the presence of oxidative lesions.
Assuntos
Óleos Voláteis/farmacologia , Piper/química , Óleos de Plantas/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Sesquiterpenos/farmacologia , Catalase/genética , Citotoxinas/farmacologia , Reparo do DNA/efeitos dos fármacos , Reparo do DNA/genética , Testes de Mutagenicidade , Mutação , Óleos Voláteis/análise , Óleos Voláteis/toxicidade , Óleos de Plantas/análise , Óleos de Plantas/toxicidade , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Sesquiterpenos/toxicidade , Superóxido Dismutase/genéticaRESUMO
We have investigated the chemical composition of Piper gaudichaudianum essential oil, as well as its cytotoxic, mutagenic and genotoxic effects in V79 cells. The chemical analyses showed that the major compounds are (E)-nerolidol (22.4%), alpha-humulene (16.5%), (E)-caryophyllene (8.9%) and bicyclogermacrene (7.4%). Dose-dependent cytotoxic effects were observed in V79 cells treated with essential oil by using clonal survival, 3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide reduction assay (MTT) and trypan blue exclusion assay (TB), and a significant decrease in survival was observed at concentrations of 0.5 microg/mL and higher. The P. gaudichaudianum essential oil treatment caused DNA strand breaks in V79 cells at concentrations up to 2 microg/mL, as detected by the alkaline comet assay, but did not induce double-strand breaks, as verified by neutral comet assay. It induced a significant increase in the frequency of micronucleated cells at 4, 6 and 10 microg/mL. Moreover, P. gaudichaudianum essential oil significantly increased lipid peroxidation at doses of 0.5 microg/mL and higher, suggesting that the observed oxidant potential can be responsible, at least in part, for its cytotoxic and genotoxic effects.
Assuntos
Fibroblastos/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Mutagênicos/toxicidade , Óleos Voláteis/toxicidade , Piperaceae/química , Óleos de Plantas/toxicidade , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Ensaio Cometa , Cricetinae , Cricetulus , Dano ao DNA , Relação Dose-Resposta a Droga , Fibroblastos/metabolismo , Fibroblastos/patologia , Cromatografia Gasosa-Espectrometria de Massas , Peroxidação de Lipídeos/efeitos dos fármacos , Pulmão/patologia , Malondialdeído/metabolismo , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Testes para Micronúcleos , Mutagênicos/análise , Óleos Voláteis/análise , Folhas de Planta/química , Óleos de Plantas/análise , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
Isoprenylation is an essential protein modification in eukaryotic cells. Herein, we report that in Plasmodium falciparum, a number of proteins were labeled upon incubation of intraerythrocytic forms with either [(3)H]farnesyl pyrophosphate or [(3)H]geranylgeranyl pyrophosphate. By thin-layer chromatography, we showed that attached isoprenoids are partially modified to dolichol and other, uncharacterized, residues, confirming active isoprenoid metabolism in this parasite. Incubation of blood-stage P. falciparum treated with the isoprenylation inhibitor limonene significantly decreased the parasites' progression from the ring stage to the trophozoite stage and at 1.22 mM, 50% of the parasites died after the first cycle. Using Ras- and Rap-specific monoclonal antibodies, putative Rap and Ras proteins of P. falciparum were immunoprecipitated. Upon treatment with 0.5 mM limonene, isoprenylation of these proteins was significantly decreased, possibly explaining the observed arrest of parasite development.
Assuntos
Antimaláricos/farmacologia , Hemiterpenos , Pentanos , Plasmodium falciparum/efeitos dos fármacos , Prenilação de Proteína/efeitos dos fármacos , Proteínas de Protozoários/metabolismo , Terpenos/farmacologia , Animais , Butadienos/metabolismo , Cromatografia em Camada Fina , Cicloexenos , Humanos , Limoneno , Testes de Sensibilidade Parasitária , Fosforilação , Plasmodium falciparum/crescimento & desenvolvimento , Plasmodium falciparum/metabolismo , Testes de Precipitina , Trítio , Proteínas ras/metabolismoRESUMO
This review, with 350 references, gives information on the chemical study of 234 naturally occurring tetraoxygenated xanthones in 12 families, 53 genus and 182 species of higher plants, and two which are described as fungal and lichen metabolites. The value of these groups of substances in connection with pharmacological activity and therapeutic use of some species is described. The structural formulas of 135 isolated compounds, and their distribution, are also given.
Assuntos
Oxigênio/química , Xantenos , Xantonas , Estrutura Molecular , Xantenos/química , Xantenos/isolamento & purificação , Xantenos/farmacologiaRESUMO
N-glycosylation of proteins is required for the intra-erythrocytic schizogony of Plasmodium falciparum. In eukaryotic cells, this process involves the transfer of oligosaccharides from a dolichyl pyrophosphate derivative to asparagine residues. We have identified dolichol, dolichyl phosphate and dolichyl pyrophosphate species of 11 and 12 isoprenoid residues by metabolic labelling with [(3)H]farnesyl pyrophosphate, [(3)H]geranylgeranyl pyrophosphate and [(14)C]acetate in the different intra-erythrocytic stages of P. falciparum. This is the first demonstration of short-chain dolichols in the phylum Apicomplexa. The results demonstrate the presence of an active isoprenoid pathway in the intra-erythrocytic stages of P. falciparum. Parasites treated with mevastatin, a 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor, show depressed biosynthesis of dolichol, dolichyl phosphate and isoprenoid pyrophosphate. This effect is observed in all intra-erythrocytic stages of the parasite life cycle, but is most pronounced in the ring stage. N-linked glycosylation of proteins was inhibited in the ring and young-trophozoite stages after mevastatin treatment of parasite cultures. Therefore the isoprenoid pathway may represent a different approach to the development of new anti-malarial drugs.
Assuntos
Dolicóis/metabolismo , Eritrócitos/parasitologia , Plasmodium falciparum/metabolismo , Animais , Dolicóis/análogos & derivados , Glicoproteínas/antagonistas & inibidores , Glicoproteínas/biossíntese , Lovastatina/análogos & derivados , Lovastatina/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/crescimento & desenvolvimentoRESUMO
Although the existence of O-linked oligosaccharide residues in glycoproteins of Plasmodium falciparum has been shown, the existence of N-linked glycoproteins is still a matter of controversy and skepticism. This report demonstrates the unequivocal presence of N-linked glycoproteins in P. falciparum, principally in the ring and young trophozoite stages of the intraerythrocytic cycle. These glycoproteins lose their capacity to bind to concanavalin A-Sepharose after treatment of cultures with tunicamycin under conditions that do not affect protein synthesis. When the glycoproteins were treated with N-Glycanase(R), oligosaccharides were released. It was possible to identify an N-linked glycoprotein of >200 kDa in the ring stage and also N-linked glycoproteins in the range of 200-30 kDa in the trophozoite stage. Treatment of trophozoites with 12 microM tunicamycin inhibited differentiation to the schizont stage. To our knowledge, this is the first report in the literature unequivocally showing N-linked glycoproteins in trophozoites of P. falciparum as well as their importance for the differentiation of the intraerythrocytic stages of this parasite.