ABSTRACT
The inhibition of 5-α reductase type 2 (SRD5A2) by finasteride is commonly used for the management of urinary obstruction resulting from benign prostatic enlargement (BPE). Certain BPE patients showing no SRD5A2 protein expression are resistant to finasteride therapy. Our previous work showed that methylated cytosine-phosphate-guanine (CpG) islands in the SRD5A2 gene might account for the absence or reduction of SRD5A2 protein expression. Here, we found that the expression of the SRD5A2 protein was variable and that weak expression of the SRD5A2 protein (scored 0-100) occurred in 10.0% (4/40) of benign adult prostates. We showed that the expression of SRD5A2 was negatively correlated with DNA methyltransferase 1 (DNMT1) expression. In vitro SRD5A2-negative BPH-1 cells were resistant to finasteride treatment, and SRD5A2 was re-expressed in BPH-1 cells when SRD5A2 was demethylated by 5-Aza-2'-deoxycytidine (5-Aza-CdR) or N-phthalyl-L-tryptophan (RG108). Furthermore, we determined the exact methylation ratios of CpG dinucleotides in a CpG island of SRD5A2 through MassArray quantitative methylation analysis. Ten methylated CpG dinucleotides, including four CpG dinucleotides in the promoter and six CpG dinucleotides in the first exon, were found in a CpG island located from -400 bp to +600 bp in SRD5A2, which might lead to the silencing of SRD5A2 and the absence or reduction of SRD5A2 protein expression. Finasteride cannot exert a therapeutic effect on patients lacking SRD5A2, which may partially account for the resistance to finasteride observed in certain BPE patients.
ABSTRACT
In response to no national standard for Gynostemma pentaphyllum, a market survey was carried out, and 17 batches of gypenosides extract and 29 batches of Gypenosides Tablets on the market were collected. With gypenoside A as an index, the TLC qualitative identification and HPLC quantitative evaluation method of gypenosides extract and tablets was established. Based on the determination results of 17 batches of gypenosides extract and 29 batches of Gypenosides Tablets, the quality standards of gypenosides extract and tablets were formulated respectively, so as to give suggestions for improving the quality standards of gypenosides extract and tablets. Compared with the existing ministerial standards, the qualitative identification and quantitative detection of specific components were added, in order to provide scientific basis and suggestions for the revision of the quality standard of gypenosides extract and tablet preparation.
Subject(s)
Gynostemma , Plant Extracts , Reference Standards , TabletsABSTRACT
To investigate the differences of chemical compositions in Gynostemma pentaphyllum leaves prepared by different processing methods. Ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) was used to compare the chemical compositions between shade-dried processing and drum-dried processing. Forty six gypenosides were identified by control comparison， liquid chromatography-mass spectrometry(LC-MSn) fragmentation information， and literature data. The mass spectral peak area statistics was combined with principal component analysis(PCA)， and the results showed that eight batches of Gynostemma pentaphyllum leaves samples were divided into two groups according to the two different processing methods; ten chemical compositions with significant differences were screened according to mass spectrum information combined with partial least-squares discriminant analysis(PLS-DA). The result showed that most parent nucleus of the gypenosides contained three to four glycosides in drum-dried samples， and one to two glycosides in the shade-dried samples. It was inferred from further MS analysis that desugarization of gypenosides was present to produce secondary glycosides with the effect of glucosidase in the shade-drying， thus resulting in difference in compositions. This study provided data support for harvesting， processing and quality control of Gynostemma pentaphyllum leaves.
Subject(s)
Chromatography, High Pressure Liquid , Gynostemma , Chemistry , Mass Spectrometry , Plant Leaves , Chemistry , Saponins , ChemistryABSTRACT
To optimize the purification process of gynostemma pentaphyllum saponins (GPS) based on "adjoint marker" online control technology with GPS as the testing index. UPLC-QTOF-MS technology was used for qualitative analysis. "Adjoint marker" online control results showed that the end point of load sample was that the UV absorbance of effluent liquid was equal to half of that of load sample solution, and the absorbance was basically stable when the end point was stable. In UPLC-QTOF-MS qualitative analysis, 16 saponins were identified from GPS, including 13 known gynostemma saponins and 3 new saponins. This optimized method was proved to be simple, scientific, reasonable, easy for online determination, real-time record, and can be better applied to the mass production and automation of production. The results of qualitative analysis indicated that the "adjoint marker" online control technology can well retain main efficacy components of medicinal materials, and provide analysis tools for the process control and quality traceability.
ABSTRACT
This paper summarized the chemical constituents and pharmacological activities of Gynostemma pentaphyllum based on systematic literature research. G. pentaphyllum mainly contains dammarane-type saponins and a total of 165 gynostemma saponins were obtained from 1976 to 2011.In recent years, some new gypenosides were isolated and identified. Two hundred and one gypenosides were classified and summarized in this paper. In addition, G. pentaphyllum also contains a variety of other chemical components including flavonoids, polysaccharides, amino acids, and trace elements, which are worth further research. The pharmacological effects of G. pentaphyllum including antitumor, regulating blood lipid, hypoglycemic, liver protection, anti-senility and improving immunity effects were summarized. This review will provide some information for further research of G. pentaphyllum.