RESUMO
Seven new xanthone glycosides (1-7) were isolated from the n-butanol extract of Swertia bimaculata, together with six known compounds (8-13). Their structures were elucidated on the basis of extensive spectroscopic analyses (1D- and 2D-NMR, HRESIMS, UV, and IR) and comparison with data reported in the literature. All the compounds were evaluated for their α-glucosidase inhibitory activities in vitro, and compounds 3, 4, and 7 exhibited significant activities to inhibit α-glucosidase. Meanwhile the effects of different substitutions on the α-glucosidase inhibitory activity of xanthone glycosides from S. bimaculata are also discussed.
Assuntos
Inibidores Enzimáticos/farmacologia , Glicosídeos/farmacologia , Extratos Vegetais/farmacologia , Swertia/química , Xantonas/farmacologia , alfa-Glucosidases/metabolismo , Inibidores Enzimáticos/química , Inibidores Enzimáticos/isolamento & purificação , Glicosídeos/química , Glicosídeos/isolamento & purificação , Estrutura Molecular , Extratos Vegetais/química , Xantonas/química , Xantonas/isolamento & purificaçãoRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Swertia macrosperma is a traditional folk medicine used for its anti-hepatitis, antipyretic and antidotal effects as "Dida" or "Zangyinchen" in Tibet, Yunnan and Guizhou province for a long time, and it has been reported for its anti-diabetic effects in a Chinese patent. Swertia macrosperma was reported rich in xanthones, iridoids, seco-iridoids and their glycosides, several of which had been documented as potential antidiabetic agents. The objective of this study was to investigate the antidiabetic effect of Swertia macrosperma in diabetic rats. MATERIALS AND METHODS: This study was designed firstly to evaluate the effect of Swertia macrosperma on glucose consumption in HepG2 cells. Based on the result in HepG2 cells, the antidiabetic effect of ethanol extract (EE) and n-butanol extract (BE) were investigated in diabetic rats induced by high fat fed and streptozotocin. The effects of EE and BE on fasting blood glucose, oral glucose tolerance test, serum insulin, glycosylated hemoglobin, serum lipid level, serum antioxidant parameters, glucokinase, glucose-6-phosphatase activities and glycogen content in liver tissue were measured, histology examination of pancreatic tissue was also carried out. RESULTS: After 4 weeks treatment with EE and BE, apparently decreased fasting blood glucose concentrations were observed in these treated groups, compared with the diabetic control groups. Additionally, improvement in serum antioxidant parameters and lipid profile were evidenced clearly. Moreover, EE and BE had effects of protecting the pancreatic ß-cells and stimulating insulin secretion from the remaining pancreatic ß-cells, evidenced by pancreatic histology examination. Increased glucokinase activity and decreased glucose-6-phosphatase activity were observed in liver. CONCLUSION: The results of in vivo and in vitro experiment suggested that EE and BE of Swertia macrosperma had excellent effects on controlling the hyperglycemia and hyperlipidemia in diabetic rats.
Assuntos
Antioxidantes/uso terapêutico , Diabetes Mellitus Experimental/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Extratos Vegetais/uso terapêutico , Swertia , Animais , Antioxidantes/farmacologia , Catalase/sangue , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/patologia , Glucoquinase/metabolismo , Glucose/metabolismo , Glucose-6-Fosfatase/metabolismo , Glutationa Peroxidase/sangue , Hemoglobinas Glicadas/análise , Glicogênio/metabolismo , Células Hep G2 , Humanos , Hipoglicemiantes/farmacologia , Insulina/sangue , Lipídeos/sangue , Fígado/efeitos dos fármacos , Fígado/enzimologia , Masculino , Malondialdeído/sangue , Pâncreas/efeitos dos fármacos , Pâncreas/patologia , Fitoterapia , Extratos Vegetais/farmacologia , Ratos , Ratos Wistar , Superóxido Dismutase/sangueRESUMO
This study was undertaken to investigate preventive effects of polysaccharides (LSP) from Liriope spicata var. prolifera on diabetic nephropathy in rats, which were induced by high fat-fed and low-dose streptozotocin (STZ). The levels of fasting blood glucose (FBG) and glycosylated hemoglobin (HbA1c) in diabetic rats were significantly decreased after treated with LSP for 28 days. Additional, the glucose tolerance of diabetes rats showed improvement after administration of LSP. The results also indicated that LSP were able to normalize hyperlipidemia, ameliorate oxidative stress, improve renal function parameters, inhibit the structural damages of kidney tissue and down-regulate the system of advanced glycation end products - receptor for advanced glycation end products (AGE-RAGE). In conclusion, LSP had potential preventive effects on diabetic nephropathy in diabetic rats.
Assuntos
Diabetes Mellitus Experimental , Nefropatias Diabéticas/metabolismo , Liriope (Planta)/química , Extratos Vegetais/farmacologia , Polissacarídeos/farmacologia , Animais , Antioxidantes/metabolismo , Glicemia , Carboidratos/química , Nefropatias Diabéticas/tratamento farmacológico , Nefropatias Diabéticas/patologia , Jejum/sangue , Teste de Tolerância a Glucose , Hemoglobinas Glicadas/metabolismo , Produtos Finais de Glicação Avançada/metabolismo , Insulina/sangue , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/patologia , Rim/fisiopatologia , Lipídeos/sangue , Masculino , Peso Molecular , Monossacarídeos/química , Extratos Vegetais/química , Polissacarídeos/química , Ratos , Receptor para Produtos Finais de Glicação Avançada , Receptores Imunológicos/metabolismoRESUMO
Ten new xanthone glycosides, kouitchensides A-J (1-10), and 11 known analogues were isolated from an n-butanol fraction of Swertia kouitchensis. The structures of these glycosides were determined on the basis of extensive spectroscopic data interpretation and comparison with data reported in the literature. In an in vitro test, compounds 2, 4, 5, 6, 11, 12, and 13 (IC50 values in the range 126 to 451 µM) displayed more potent inhibitory effects against α-glucosidase activity than the positive control, acarbose (IC50 value of 627 µM).
