Gynostemma pentaphyllum polysaccharides ameliorate non-alcoholic steatohepatitis in mice associated with gut microbiota and the TLR2/NLRP3 pathway.

Recent studies have revealed the pivotal role of gut microbiota in the progress of liver diseases including non-alcoholic steatohepatitis (NASH). Many natural herbs, such as Gynostemma pentaphyllum (GP), have been extensively applied in the prevention of NASH, while the bioactive components and underlying mechanism remain unclear. The aim of this study was to investigate whether the polysaccharides of GP (GPP) have a protective effect on NASH and to explore the potential mechanism underlying these effects. C57BL/6 male mice were fed with a methionine-choline-deficient (MCD) diet for 4 weeks to induce NASH and administered daily oral gavage of sodium carboxymethylcellulose (CMC-Na), low dose of GPP (LGPP), high dose of GPP (HGPP), and polyene phosphatidylcholine capsules (PPC), compared with the methionine-choline-sufficient (MCS) group. Our results showed that the symptoms of hepatic steatosis, hepatocyte ballooning, liver fibrosis, and oxidative stress could be partially recovered through the intervention of GPP with a dose-dependent effect. Furthermore, gut microbiome sequencing revealed that HGPP altered the composition of gut microbiota, mainly characterized by the enrichment of genera including Akkermansia, Lactobacillus, and A2. Moreover, hepatic transcriptome analysis indicated that the anti-inflammatory effect of HGPP might be associated with toll-like receptor (TLR) and nod-like receptor (NLR) signaling pathways. HGPP could inhibit the expression of TLR2 and downregulate the expression of the NLRP3 inflammasome, as well as the pro-inflammatory cytokine tumor necrosis factor (TNF)-α and interleukin (IL)-1ß. In summary, GPP could ameliorate NASH possibly mediated via the modulation of gut microbiota and the TLR2/NLRP3 signaling pathway, indicating that GPP could be tested as a prebiotic agent in the prevention of NASH.

A novel natural PPARγ agonist, Gypenoside LXXV, ameliorates cognitive deficits by enhancing brain glucose uptake via the activation of Akt/GLUT4 signaling in db/db mice.

Targeting the PPARγ might be a potential therapeutic strategy for diabetes-associated cognitive decline (DACD). In this study, Gypenoside LXXV (GP-75), a dammarane-type triterpene compound isolated from Gynostemma pentaphyllum, was found to be a novel PPARγ agonist using a dual-luciferase reporter assay system. However, whether GP-75 has protective effects against DACD remains unknown. Interestingly, intragastric administration of GP-75 (40 mg/kg/day) for 12 weeks significantly attenuated the cognitive deficit in db/db mice. GP-75 treatment significantly improved the glucose tolerance and lipid metabolism, and suppressed neuroinflammation. Notably, GP-75 treatment dramatically increased the uptake of glucose by the brain, as detected by 18 F-FDG PET. Incubation of primary cortical neurons with GP-75 significantly increased 2-deoxyglucose uptake. In addition, GP-75 treatment markedly increased the p-Akt (Ser 473)/total Akt levels and the expression levels of PPARγ and GLUT4, while decreasing the levels of p-IRS-1 (Ser 616)/total IRS-1. Importantly, all of these protective effects mediated by GP-75 were abolished by cotreatment with the PPARγ antagonist, GW9662. However, GP-75-mediated PPARγ upregulation was not affected by coincubation with the phosphatidylinositol 3-kinase inhibitor, LY294002. Collectively, GP-75 might be a novel PPARγ agonist that ameliorates cognitive deficit by enhancing brain glucose uptake via the activation of Akt/GLUT4 signaling in db/db mice.

Gene excavation and expression analysis of CYP and UGT related to the post modifying stage of gypenoside biosynthesis in Gynostemma pentaphyllum (Thunb.) Makino by comprehensive analysis of RNA and proteome sequencing.

Previous studies have revealed that gypenosides produced from Gynostemma pentaphyllum (Thunb.) Makino are mainly dammarane-type triterpenoid saponins with diverse structures and important biological activities, but the mechanism of diversity for gypenoside biosynthesis is still unclear. In this study, a combination of isobaric tags for relative and absolute quantification (iTRAQ) proteome analysis and RNA sequencing transcriptome analysis was performed to identify the proteins and genes related to gypenoside biosynthesis. A total of 3925 proteins were identified by proteomic sequencing, of which 2537 were quantified. Seventeen cytochrome P450 (CYP) and 11 uridine 5'-diphospho-glucuronosyltransferase (UDP-glucuronosyltransferase, UGT) candidate genes involved in the side chain synthesis and modification of gypenosides were found. Seven putative CYPs (CYP71B19, CYP77A3, CYP86A7, CYP86A8, CYP89A2, CYP90A1, CYP94A1) and five putative UGTs (UGT73B4, UGT76B1, UGT74F2, UGT91C1 and UGT91A1) were selected as candidate structural modifiers of triterpenoid saponins, which were cloned for gene expression analysis. Comprehensive analysis of RNA sequencing and proteome sequencing showed that some CYPs and UGTs were found at both the transcription and translation levels. In this study, an expression analysis of 7 CYPs and 5 UGTs that contributed to gypenoside biosynthesis and distribution in G. pentaphyllum was performed, providing consistent results that will inspire more future research on vital genes/proteins involved in gypenoside biosynthesis.

Research on the Potential Mechanism of Gypenosides on Treating Thyroid-Associated Ophthalmopathy Based on Network Pharmacology.

Thyroid-associated ophthalmopathy is the commonest orbital disease in adults. However, shortcomings still exist in treatments. The aim of this study was to identify the efficacy and potential mechanism of gypenosides in the treatment of thyroid-associated ophthalmopathy. The Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform was screened for active compounds of gypenosides, and targets were predicted using Swiss Target Prediction. The targets of thyroid-associated ophthalmopathy were obtained from Online Mendelian Inheritance in Man, Comparative Toxicogenomic Database and GeneCards Human gene database. Gene Ontology (GO), the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Reactome Pathways were determined based on the common targets. Protein-protein interaction (PPI) network was constructed to further understand of relationship among target genes, compounds and proteins. Molecular docking was performed to investigate the binding ability between gypenosides and hub genes. A total of 70 targets for gypenosides and 804 targets for thyroid-associated ophthalmopathy were obtained with 8 common targets identified. GO analysis and KEGG pathway analysis revealed that the hub genes were enriched in JAK-STAT, while Reactome pathways analysis indicated genes enriched in interleukin pathways. PPI network showed STAT1, STAT3, and STAT4 were at the center. Additionally, molecular docking indicated that STAT1 and STAT3 display good binding forces with gypenosides. This study indicates that target genes mainly enriched in JAK-STAT signaling pathway, particularly in STATs, which can be combined with gypenosides. This may suggest that gypenosides have curative effect on thyroid-associated ophthalmopathy via the JAK-STAT pathway.

Simultaneous determination of gypenoside LVI, gypenoside XLVI, 2α-OH-protopanaxadiol and their two metabolites in rat plasma by LC-MS/MS and its application to pharmacokinetic studies.

Gypenoside LVI and gypenoside XLVI are the major bioactive dammarane saponins from Gynostemma pentaphyllum. Gypenoside LVI, gypenoside XLVI, and their metabolite 2α-OH-protopanaxadiol (2α-OH-PPD) possess potent non-small cell lung carcinoma A549 cell inhibitory activity. A sensitive liquid chromatography tandem mass spectrometry method was developed and validated to study the pharmacokinetics of gypenoside LVI and XLVI, 2α-OH-PPD, metabolite 1 (M1), and metabolite 2 (M2) after administration of gypenosides or 2α-OH-PPD. Plasma samples from rats were protein precipitated with methanol. Analytes were detected by triple quadrupole MS/MS with an electrospray ionization source in the positive multiple reaction monitoring mode. The transition m/z 441.4→109.2 was selected to quantify gypenoside LVI and XLVI, and 2α-OH-PPD, because of the extensive conversion of the gypenosides to aglycone in the ionization source. M1 and M2 are isomers that shared the transition m/z 493.4→143.1. To avoid interference, the baseline separation of each analyte was performed on a SunFire C18 column with a gradient of acetonitrile (0.1% formic acid, v/v) and water (0.1% formic acid, v/v). The chromatographic run time was 10min. The linearity was validated over a plasma concentration range from 2.00 to 2000ng/mL for M1 and M2, and from 10.0 to 2000 for gypenosides LVI and XLVI, and 2α-OH-protopanaxadiol. The lower limits of quantification were 10.0, 10.0, 10.0, 2.00, and 2.00ng/mL for gypenoside LVI, gypenoside XLVI, 2α-OH-PPD, M1, and M2, respectively, with acceptable intra-/inter-day precision and accuracy. The extraction recovery rates were >86.9% for each compound. No apparent matrix effect or instability was observed during each step of the bioanalysis. After full validation, this method was proved to be simple, fast, and efficient in analyzing large batches of plasma samples for the analytes.

In vitro inhibitory activities of six gypenosides on human liver cancer cell line HepG2 and possible role of HIF-1α pathway in them.

During our phytochemical investigation of Gynostemma pentaphyllum (Thunb.) Makino, six gypenosides (compounds 1-6) were isolated and determined, including two with a 21,23-epoxy group (1, 2), two with a 21,23-lacton skeleton (3, 4), and two with usual side-chain (5, 6). In this research, we studied their possible in vitro inhibitory activities on cancer cell line HepG2 under hypoxic conditions, explored the role of HIF-1α pathway in them and discussed the potential antitumor gradients and conduct analysis of structure-activity relationships (SAR). They and gensenoside-Rg3 were tested for different assays. Compounds 1-4 showed moderate antitumor activities against HepG2 by MTT assay, inhibited HIF-1α mRNA expression, as well as disturbing HepG2 migration and invasion, superior to Rg3. Correlations were found for gypenosides with different side chain on inhibiting HepG2 proliferation activity, the ones have epoxy structure showed the highest effect. These results supported the potential application of G. pentaphyllum as a functional food for hepatoprotection.

Novel dammarane-type triterpenes isolated from hydrolyzate of total Gynostemma pentaphyllum saponins.

In this study, five novel triterpenes were isolated from hydrolyzate of total saponins from Gynostemma pentaphyllum and identified as gypensapogenin H (1), gypensapogenin I (2), gypensapogenin L (3), gypensapogenin J (4) and gypensapogenin K (5), three of which (1-3) possess unprecedented ring A. All the isolated compounds were evaluated for cytotoxic activities in five cell lines and all the tested compounds showed significant anti-cancer activities against a series of human cancer cell lines, while having much weaker effect on the growth of normal cell. Among them, compound 1 showed strong inhibition toward MCF-7 human breast cancer cells (IC50 values 6.85 µM). Further mechanistic study demonstrated that compound 1 significantly induced MCF-7 cell apoptosis. Our results indicated that compound 1 may be a promising lead agent for further study.

Metabolic profiling of Gynostemma pentaphyllum extract in rat serum, urine and faeces after oral administration.

Folk drug Gynostemma pentaphyllum (Thunb.) Makino contains many biologically active phytochemicals which have been demonstrated to be effective against chronic diseases. As in vivo anti-tumor experiments of G. pentaphyllum extract (GP) show much stronger antitumor activities than in vitro, it is important and necessary to understand the metabolic study of GP. A sensitive and specific U-HPLC-MS method was utilized for the first time to rapidly identify gypenosides and its possible metabolites in rat serum, urine, and faeces after oral administration. Solid phase extraction was utilized in the sample preparation. Negative Electrospray ionisation (ESI) mass spectrometry was used to discern gypenosides and its possible metabolites in rat samples. As a result, after oral administration, a total of seven metabolites of G. pentaphyllum extract were assigned, two from the rat serum and seven both from the rat urine and faeces. As metabolites of G. pentaphyllum extract, all of them have never been reported before.

Determination by UPLC-MS of four dammarane-type saponins from heat-processed Gynostemma pentaphyllum.

Heat-processed Gynostemma pentaphyllum and its main dammaran-type saponins, gypenoside L, gypenoside LI, damulin B, and damulin A, possess non-small cell lung carcinoma A549 cell inhibitory activity. We established in this study a method by ultra-high performance liquid chromatography with tandem mass spectrometry for determination of the saponins and also investigated their content change in heat-processed G. pentaphyllum. The main saponins increased with increasing heating temperature and time. Further investigation showed that they were produced from gypenoside XLVI and gypenoside LVI by undergoing hydrolysis during the heat treatment.

Nine new dammarane saponins from Gynostemma pentaphyllum.

Nine new dammarane saponins, 1-9, were isolated from the MeOH extract of the aerial part of Gynostemma pentaphyllum, an edible plant of the Cucurbitaceae family, that grows wildly in China. Their structures were elucidated by 1D- and 2D-NMR analysis, as well as by chemical degradation. Aglycons 21,24-cyclopentyldammar-25-ene of 6 and 7, and 21,24-cyclopentyldammarane of 8 and 9, were novel. Compounds 1, 4, and 8 showed moderate antitumor activities against stomach cancer cells SGC-7901 and liver cancer cells BEL-7402.

[Dynamic features of some biochemical constituents in Gynostemma pentaphyllum under different environments].

With biochemical techniques, the authors preliminarilty examined the dynamics of polyphenols, free amino acids and water-soluble sugars in Gynostemma pentaphyllum collected from different regions and the relationships between them and climate factors. The dynamic patterns of these three types of constituents in stems, blades and shoots under the same environment were different. At different growth phases, stems and blades had different contributions to the constituents. The dynamics of them differed with their environments. Polyphenols, free amino acids and water-soluble sugars might regulate the growth and development of plants. Moreover, they were characterized by plasticity, and the dominant climate factors affecting the dynamics of the constituents varied greatly.