RESUMEN
This study is to develop a method for isolation, identification, and quantitative determination of dammarane-type triterpene saponins in the Panax notoginseng fruits (PNF). The saponins were isolated by a serious of chromatographic methods, and their structures were elucidated on the basis of spectroscopic evidence and comparison with those of literature reports. Quantitative assay was performed on an ultra-performance liquid chromatography-UV (UPLC-UV) method. As a result, 22 saponins were isolated from the extract of PNF, among them, compound 1 was a new saponin, named as malonylgypenoside IX, compounds 3-10, and 14-18 were isolated from the PNF for the first time. As to quantitative analysis, the calibration curves showed good linearity (r > 0.998) within the concentration range, and the method validation provided good reproducibility and sensitivity for the quantification of eight major saponins with precision and accuracy of less than 3.0%.
Asunto(s)
Panax notoginseng , Panax , Saponinas , Triterpenos , Cromatografía Líquida de Alta Presión/métodos , Frutas/química , Panax/química , Panax notoginseng/química , Extractos Vegetales , Reproducibilidad de los Resultados , Saponinas/química , Triterpenos/químicaRESUMEN
Physalin B (PB), one of the major active steroidal constituents of Solanaceae Physalis plants, has a wide variety of biological activities. We found that PB significantly down-regulated ß-amyloid (Aß) secretion in N2a/APPsw cells. However, the underlying mechanisms are not well understood. In the current study, we investigated the changes in key enzymes involved in ß-amyloid precursor protein (APP) metabolism and other APP metabolites by treating N2a/APPsw cells with PB at different concentrations. The results indicated that PB reduced Aß secretion, which was caused by down-regulation of ß-secretase (BACE1) expression, as indicated at both the protein and mRNA levels. Further research revealed that PB regulated BACE1 expression by inducing the activation of forkhead box O1 (FoxO1) and inhibiting the phosphorylation of signal transducer and activator of transcription 3 (STAT3). In addition, the effect of PB on BACE1 expression and Aß secretion was reversed by treatment with FoxO1 siRNA and STAT3 antagonist S3I-201. In conclusion, these data demonstrated that PB can effectively down-regulate the expression of BACE1 to reduce Aßsecretion by activating the expression of FoxO1 and inhibiting the phosphorylation of STAT3.
Asunto(s)
Enfermedad de Alzheimer , Secretasas de la Proteína Precursora del Amiloide , Secretasas de la Proteína Precursora del Amiloide/genética , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Péptidos beta-Amiloides/metabolismo , Ácido Aspártico Endopeptidasas/genética , Ácido Aspártico Endopeptidasas/metabolismo , Regulación hacia Abajo , Proteína Forkhead Box O1/genética , Humanos , Fosforilación , Factor de Transcripción STAT3/genética , Factor de Transcripción STAT3/metabolismo , SecoesteroidesRESUMEN
Four new malonylginsenosides, malonylnotoginsenoside Fe (1), malonylnotoginsenoside Ra1 (2), malonylgypenoside LXXV (3), and malonylginsenoside Mc (4), together with two known analogues, malonylfloralginsenoside Rc1 (5) and malonylginsenoside Rc (6), were isolated from the fresh fruits of Panax notoginseng. Their structures were determined by MS and NMR experiments. The anti-proliferative activities of the malonylginsenosides (1-6) against SH-SY5Y human neuroblastoma cell line were evaluated using the MTT assay.