The potential molecular mechanism underlying gypenoside amelioration of atherosclerosis in ApoE-/- mice: A multi-omics investigation

Gypenosides (Gyp) are bioactive components of Gynostemma pentaphyllum that have a variety of pharmacological properties. Extracts of G. pentaphyllum have been found to be effective in the reduction of blood sugar and lipids and prevention of atherosclerosis. Here, the functions of Gyp and the mechanisms underlying their effects on atherosclerosis were investigated. Mice were allocated to three groups, namely, the control (C57BL/6), atherosclerosis model (ApoE-/- mice with high-fat diet), and Gyp-treated groups. Differentially expressed mRNAs, miRNAs, circRNA, and differential metabolites among the groups were analyzed. The results showed that "Fatty acid metabolism", "Fatty acid elongation", "Cytokine-cytokine receptor interaction", and "PI3K-Akt signaling pathway", amongst others, were involved in treatment process. Differentially expressed genes, including Fabp1, Apoe, FADS1, ADH1, SYNPO2, and Lmod1were also identified. Mmu-miR-30a and mmu-miR-30e showed reduced expression in atherosclerosis models but were increased following Gyp treatment, suggesting involvement in the effects of Gyp. In addition, chr5:150604177-150608440 were found to interact with mmu-miR-30a and mmu-miR-30e to regulate their abundance. In terms of metabolomics, Gyp may regulate biological processes involving PGD2 and PGJ2, potentially alleviating atherosclerosis. In conclusion, Gyp appeared to have complex effects on atherosclerosis, most of which were positive. These results support the use of Gyp in the treatment of atherosclerosis.

Saponins derived from Gynostemma pentaphyllum regulate triglyceride and cholesterol metabolism and the mechanisms: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Gynostemma pentaphyllum (Thunb.) Makino (G. pentaphyllum) can be used for both medicinal and tea and has lipid-lowering properties. Modern research has shown that its main bioactive components are flavonoids and saponins. It has many beneficial effects such as hypolipidemic, anti-cancer, cardioprotective, hepatoprotective, neuroprotective, anti-diabetic and anti-inflammatory.

AIMS OF THE REVIEW

This review aimed to summarize its anti-glycolipid metabolic models and mechanisms are reviewed to facilitate a deeper understanding of the mechanism in lowering lipids.

MATERIALS AND METHODS

Information related to lipid lowering in G. pentaphyllum was collated by reviewing the relevant literature in the PubMed database from 1985 to 2023.

RESULTS

Only 101 G. pentaphyllum compounds have been initially explored for their hypolipidemic activity. There are cell models, animal models and human subjects for lipid-lowering of it. It reduced triglyceride level via PPAR/UCP-1/PGC-1α/PRDM16 and (SREBP-1c)-ACC/FAS-CPT1 signal pathways. Cholesterol-lowering effects via (SREBP-2)-HMGCR, PCSK9-LDLR and bile acid biosynthetic pathways. Activation of adenosine 5'-monophosphate-activated protein kinase (AMPK) is a key factor in the regulation of glycolipid metabolism in G. pentaphyllum. Other pathways of action of G. pentaphyllum in regulating glucolipid metabolism are also discussed in this paper.

CONCLUSION

To date, more than 328 saponins have been isolated and identified in Gynostemma. Further studies on these components, including molecular mechanisms and in vivo metabolic regulation, need to be further confirmed. G. pentaphyllum has the potential to be developed into drugs or functional foods, but further research is needed.

Gypenosides suppress hepatocellular carcinoma cells by blocking cholesterol biosynthesis through inhibition of MVA pathway enzyme HMGCS1

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with high morbidity and mortality. Targeting abnormal cholesterol metabolism is a potential therapeutic direction. Therefore, more natural drugs targeting cholesterol in HCC need to be developed. Gypenosides (Gyp), the major constituent of Gynostemma pentaphyllum, has been demonstrated to have pharmacological properties on anti-cancer, anti-obesity, and hepatoprotective. We investigated whether Gyp, isolated and purified by our lab, could inhibit HCC progression by inhibiting cholesterol synthesis. The present research showed that Gyp inhibited proliferation and migration, and induced apoptosis in Huh-7 and Hep3B cells. Metabolomics, transcriptomics, and target prediction all suggested that lipid metabolism and cholesterol biosynthesis were the mechanisms of Gyp. Gyp could limit the production of cholesterol and target HMGCS1, the cholesterol synthesis-related protein. Downregulation of HMGCS1 could suppress the progression and abnormal cholesterol metabolism of HCC. In terms of mechanism, Gyp suppressed mevalonate (MVA) pathway mediated cholesterol synthesis by inhibiting HMGCS1 transcription factor SREBP2. And the high expression of HMGCS1 in HCC human specimens was correlated with poor clinical prognosis. The data suggested that Gyp could be a promising cholesterol-lowering drug for the prevention and treatment of HCC. And targeting SREBP2-HMGCS1 axis in MVA pathway might be an effective HCC therapeutic strategy.

Gypenosides suppress fibrosis of the renal NRK-49F cells by targeting miR-378a-5p through the PI3K/AKT signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The incidence of renal fibrosis caused by chronic kidney disease is increasing year by year. Preventing the activation and conversion of kidney-intrinsic fibroblasts to a myofibroblast phenotype is an important target for blocking the development of renal interstitial fibrosis. Our team established a stable renal interstitial fibrosis cell model in the early stage, and the screening results showed that GPs has good anti-fibrosis potential. At this stage, only a few literatures have reported its anti-fibrosis effect, and the mechanism of action is still unclear.

AIM OF THE STUDY

The massive synthesis and secretion of extracellular-matrix (ECM) components by activated fibroblasts in the kidneys causes irreversible renal interstitial fibrosis. Gypenosides (GPs) have been shown to decelerate this process, in which micro RNAs (miRNAs) play an important regulatory role. This study aimed to evaluate the mechanism underlying the suppressive effect of GPs on renal fibrosis.

MATERIALS AND METHODS

This study used TGF-β1-stimulated NRK-49F renal cells as an in-vitro model of renal interstitial fibrosis. First, the concentration range of GPs that significantly affects the cytoactive was determined. Then, the anti-fibrotic effects of various concentrations of GPs in the in-vitro model were assessed via immunofluorescence, western blotting, and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Non-coding-RNA sequencing combined with bioinformatics was used to predict the mechanistic basis of the anti-fibrotic effect of GPs, and qRT-PCR was used to verify the sequencing results and bioinformatic predictions. The identified relationships of the anti-fibrotic effect of GPs with miR-378a-5p and the PI3K/AKT signaling were evaluated using a miR-NC mimic and the PI3K inhibitor LY294002 as controls, respectively.

RESULTS

TGF-β1 stimulation up-regulated α-SMA, COL1, and COL3 in NRK-49F cells, and this effect was suppressed by GPs. Additionally, TGF-β1 stimulation significantly changed the expression levels of 151 miRNAs, and GPs significantly suppressed the effect of TGF-β1 on the levels of 18 of these miRNAs. Among them, miR-3588 and miR-378a-5p were down-regulated, and miR-135b-5p and miR-3068-5p were up-regulated upon TGF-β1 induction. Of these miRNAs, miR-378a-5p was predicted to target the mRNAs of numerous proteins mainly enriched in the PI3K/AKT signaling pathway. The miRNA transfection experiments with the miR-NC mimic and PI3K inhibitor as controls showed that miR-378a-5p overexpression could suppress the TGF-β1-induced up-regulation of α-SMA, COL1, PI3K, and AKT, including the phosphorylated form (p-AKT).

CONCLUSION

GPs inhibit the PI3K/AKT signaling by up-regulating miR-378a-5p in TGF-β1-stimulated NRK-49F cells and thereby reduce their massive secretion of ECM components. Given that this in-vitro model of renal interstitial fibrosis closely mimics the in-vivo pathogenesis, our results most likely apply to the in-vivo conditions.

Liver lipidomics analysis reveals the anti-obesity and lipid-lowering effects of gypnosides from heat-processed Gynostemma pentaphyllum in high-fat diet fed mice

BACKGROUND

In traditional Chinese medicine, Gynostemma pentaphyllum (G. pentaphyllum) is widely used to treat conditions associated with hyperlipidemia, and its therapeutic potential has been demonstrated in numerous studies. However, the mechanism of lipid metabolism in hyperlipidemic by G. pentaphyllum, especially heat-processed G. pentaphyllum is not yet clear.

PURPOSE

The aim of this study was to investigate the therapeutic mechanism of gypenosides from heat-processed G. pentaphyllum (HGyp) in hyperlipidemic mice by means of a lipidomics.

METHODS

The content of the major components of HGyp was determined by ultra-performance liquid chromatography-electrospray ionization ion trap mass spectrometry (UPLC-ESI-MS). An animal model of hyperlipidaemia was constructed using C57BL/6J mice fed with high-fat diet. HGyp was also administered at doses of 50, 100 and 200 mg/kg, all for 12 weeks. Serum parameters were measured, histological sections were prepared and liver lipidome analysis using UPLC-MS coupled with multivariate statistical analysis. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting were used to analyze the genes and proteins associated with lipid lowering in HGyp.

RESULTS

HGyp reduced body weight, serum total cholesterol (TC), triglyceride (TG) and low-density lipoprotein (LDL) and hepatic lipid accumulation in hyperlipidemic obese mice. To explore specific changes in lipid metabolism in relation to HGyp administration, lipid analysis of the liver was performed. Orthogonal partial least squares discriminant analysis (OPLS-DA) score plots showed that HGyp altered lipid metabolism in HFD mice. In particular, fatty acids (FA), triglycerides (DG), TG and ceramides (CER) were significantly altered. Eleven lipids were identified as potential lipid biomarkers, namely TG (18:2/20:5/18:2), TG (18:2/18:3/20:4), DG (18:3/20:0/0:0), Cer (d18:1/19:0), Cer (d16:1/23:0), Ceramide (d18:1/9Z-18:1), PS (19:0/18:3), PS (20:2/0:0), LysoPC (22:5), LysoPE (0:0/18:0), PE (24:0/16:1). Western blot and qRT-PCR analysis showed that these metabolic improvements played a role by down-regulating genes and proteins related to fat production (SREBP1, ACC1, SCD1), up-regulating genes and proteins related to lipid oxidation (CPTA1, PPARα) and lipid transport decomposition in the bile acid pathway (LXRα, PPARγ, FXR, BSEP).

CONCLUSION

The lipid-lowering effect of gypenosides from heat-processed G. pentaphyllum is regulate lipid homeostasis and metabolism.

Gypenosides ameliorate high-fat diet-induced nonalcoholic fatty liver disease in mice by regulating lipid metabolism

Gypenosides (GP), extracted from the traditional Chinese herb Gynostemma pentaphyllum (Thunb.) Makino, have been used to treat metabolic disorders, including lipid metabolism disorders and diabetes. Although recent studies have confirmed their beneficial effects in nonalcoholic fatty liver disease (NAFLD), the underlying therapeutic mechanism remains unclear. In this study, we explored the protective mechanism of GP against NAFLD in mice and provided new insights into the prevention and treatment of NAFLD. Male C57BL6/J mice were divided into three experimental groups: normal diet, high-fat diet (HFD), and GP groups. The mice were fed an HFD for 16 weeks to establish an NAFLD model and then treated with GP for 22 weeks. The transcriptome and proteome of the mice livers were profiled using RNA sequencing and high-resolution mass spectrometry, respectively. The results showed that GP decreased serum lipid levels, liver index, and liver fat accumulation in mice. Principal component and heatmap analyses indicated that GP significantly modulated the changes in the expression of genes associated with HFD-induced NAFLD. The 164 differentially expressed genes recovered using GP were enriched in fatty acid and steroid metabolism pathways. Further results showed that GP reduced fatty acid synthesis by downregulating the expression of Srebf1, Fasn, Acss2, Acly, Acaca, Fads1, and Elovl6; modulated glycerolipid metabolism by inducing the expression of Mgll; promoted fatty acid transportation and degradation by inducing the expression of Slc27a1, Cpt1a, and Ehhadh; and reduced hepatic cholesterol synthesis by downregulating the expression of Tm7sf2, Ebp, Sc5d, Lss, Fdft1, Cyp51, Nsdhl, Pmvk, Mvd, Fdps, and Dhcr7. The proteomic data further indicated that GP decreased the protein expression levels of ACACA, ACLY, ACSS2, TM7SF2, EBP, FDFT1, NSDHL, PMVK, MVD, FDPS, and DHCR7 and increased those of MGLL, SLC27A1, and EHHADH. In conclusion, GP can regulate the key genes involved in hepatic lipid metabolism in NAFLD mice, providing initial evidence for the mechanisms underlying the therapeutic effect of GP in NAFLD.

Sensory-guided isolation and identification of new sweet-tasting dammarane-type saponins from Jiaogulan (Gynostemma pentaphyllum) herbal tea

The purpose of this study was to elucidate the chemical basis for the sweet property produced by Gynostemma pentaphyllum and find new natural high-potency (HP) sweeteners. Sixteen new compounds (gypenosides YN 1-16) were obtained by sensory-guided isolation and identification, in which fifteen of them were sweet-tasting constituents with sweetness intensities 10-100 times higher than that of sucrose evaluated by human sensory panel test. Their structures were established by 1D and 2D nuclear magnetic resonance spectra, mass spectroscopy, infrared spectroscopy, UV-visible spectroscopy, and chemical method. Gypenoside YN 4 was the sweetest compound with a concentration of 15.504 ± 1.343 mg/kg, while gypenoside YN 12 has the highest concentration (1397.674 ± 12.948 mg/kg), as shown by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Structure-activity relationship analysis implied that the compounds' sweetness intensity was associated with side-chain substitutions at C-20 or the number of glucosyl groups at C-3. These new plant-derived natural products may be potential natural sweeteners.

Effects of heat-processed Gynostemma pentaphyllum on high-fat diet-fed mice of obesity and functional analysis on network pharmacology and molecular docking strategy

ETHNOPHARMACOLOGICAL RELEVANCE

Gynostemma pentaphyllum has been used as traditional medicine for many diseases, including metabolic syndrome (Mets), aging, diabetes, neurodegenerative diseases in China, some East Asian and Southeast Asian countries. It was shown that G. pentaphyllum and gypenosides had anti-obesity and cholesterol-lowering effects too. However, its main active ingredients are still unclear.

AIMS

The objective of this study was to compare the effects of gypenosides before and after heat-processing on high fat obese mice, and to analyze the function of G. pentaphyllum saponin via network pharmacology and molecular docking.

METHODS

The leaves of G. pentaphyllum were heat processed at 120 °C for 3 h to obtain heat-processed G. pentaphyllum. Gypenosides (Gyp) and heat-processed gypenosides (HGyp) were prepared by resin HP-20 chromatography and analyzed using LC-MS from the extracts of G. pentaphyllum before and after heat-processing, respectively. Obesity model was made with high fat diet (HFD). Gyp and HGyp were administrated at 100 mg/kg for 12 weeks in HFD obese mice and the body weight, energy intake, and levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL) were compared. HGyp was administrated at a dose of 50,100,200 mg/kg for 12 weeks in HFD obese mice and the perirenal adipose, epididymal adipose, abdominal adipose, shoulder brown adipose, inguinal adipose were measured. Moreover, the potential targets, hub genes and pathways of damulin A, damulin B, gypenoside L, gypenoside LI for treating Mets were screened out via network pharmacology. According to the results of network pharmacology, core targets of treating Mets were docking with damulin A, gypenoside L, damulin B, gypenoside LI via molecular docking.

RESULTS

HGyp showed stronger effects on body weight loss and lipid-lowering in obese mice than Gyp. The contents of gypenoside L, gypenoside LI, damulin A and damulin B of G. pentaphyllum were increased by heat-processing. HGyp significantly decreased the body weight, calorie intake, and levels of TC, TG, LDL, HDL on the obese mice. It up-regulated PPARα and PPARγ in the liver tissues. HGyp reduced significantly the size of adipocytes in inguinal, abdominal, epididymal adipose and increased the proportion of interscapular brown fat. Network pharmacology results showed that 21 potential targets and 12 related-pathways were screened out. HMGCR, ACE, LIPC, LIPG, PPARα PPARδ, PPARγ were the core targets of HGyp against lipid metabolism by molecular docking. The putative functional targets of HGyp may be modulated by AGE-RAGE, TNF, glycerolipid metabolism, lipid and atherosclerosis, cholesterol metabolism, PPAR, fat digestion and absorption, cell adhesion molecules signaling pathway.

CONCLUSIONS

Gyp and HGyp are valuable for inhibition obesity, lipid-lowering, metabolic regulation. Especially, the effect of HGyp is better than that of Gyp.

Gypenosides Prevent and Dissolve Cholesterol Gallstones by Modulating the Homeostasis of Cholesterol and Bile Acids

Gypenosides (GPs), obtained from Gynostemma pentaphyllum (Thunb.) Makino, have been traditionally prescribed to treat metabolic disorders in Asians. This study assessed whether GPs could prevent lithogenic diet (LD)-induced cholesterol gallstone (CG) formation and enhance CG dissolution in mice. Gallstone-susceptible C57BL/6J mice were fed an LD or normal chow, with or without GPs. Bile acids (BAs) in gallbladder bile were analyzed by liquid chromatography-tandem mass spectrometry. Differentially expressed hepatic genes were identified by RNA sequencing, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. GPs were found to prevent LD-induced CG formation and to dissolve pre-existing LD-induced CGs. GPs reduced total cholesterol levels and increased BA levels in bile, as well as reducing the BA Hydrophobicity Index, ratio of 12α-hydroxylated (12α-OH) to non-12α-OH BAs, and Cholesterol Saturation Index in gallbladder bile. GO and KEGG pathway enrichment analyses indicated that GPs-induced genes were involved in BA biosynthesis and cholesterol metabolism. GPs increased the hepatic expression of genes encoding the cytochrome P450 (Cyp) enzymes Cyp7a1, Cyp7b1, and Cyp8b1, while decreasing the hepatic expression of genes encoding the adenosine triphosphate-binding cassette (Abc) transporters Abcg5 and Abcg8. GPs may be a promising strategy for preventing and dissolving CGs.

Uncovering the anti-NSCLC effects and mechanisms of gypenosides by metabolomics and network pharmacology analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Lung cancer is the chief reason of cancer death worldwide, and non-small cell lung cancer (NSCLC) make up the majority of lung cancers. Gypenosides are the main active constituents from Gynostemma pentaphyllum. Previous studies showed that they were used to remedy many cancers. The effect of gypenosides on NSCLC has never been studied from the perspective of network pharmacology and metabolomics. The mechanism is still not clear and remains to be explored.

AIM OF THE STUDY

To explore the anti-NSCLC activity and mechanism of gypenosides in A549 cells.

MATERIAL/METHODS

Gypenosides of G. pentaphyllum were detected by HPLC-MS. The cytotoxicity was detected by MTT assay. The migration, cell cycle and apoptosis of gypenosides were studied by wound healing assay, JC-1 assay and flow cytometry. The mechanism of gypenosides on NSCLC was studied by metabolomics and network pharmacology. Some key proteins and pathways were further confirmed by Western blot.

RESULTS

Eleven gypenosides were detected by HPLC-MS. Gypenosides could suppress the proliferation of A549 cells, inhibit the migration of A549 cells, induce apoptosis and arrest cell cycle in G0/G1 phase. Metabolomics and network pharmacology approach revealed that gypenosides might affect 17 metabolite related proteins by acting on 9 candidate targets (STAT3, VEGFA, EGFR, MMP9, IL2, TYMS, FGF2, HPSE, LGALS3), thus resulting in the changes of two metabolites (uridine 5'-monophosphate, D-4'-Phosphopantothenate) and two metabolic pathways (pyrimidine metabolism; pantothenate and CoA biosynthesis). Western blotting indicated that gypenosides might inhibit A549 cells through MMP9, STAT3 and TYMS to indirectly affect the pathways of pyrimidine metabolism, pantothenate and CoA biosynthesis.

CONCLUSIONS

This study revealed that metabolomics combined with network pharmacology was conducive to understand the anti-NSCLC mechanism of gypenosides.

Unraveling the metabolic pathway of choline-TMA-TMAO: Effects of gypenosides and implications for the therapy of TMAO related diseases

Trimethylamine-N-oxide (TMAO) has emerged as a promising new therapeutic target for the treatment of central nervous system diseases, atherosclerosis and other diseases. However, its origin in the brain is unclear. Gynostemma pentaphyllum (Thunb.) Makino can reduce the increase of TMAO level caused by a high fat diet. But its effective chemical composition and specific mechanism have not been reported. The study confirmed that TMA was more easily to penetrate blood brain barrier than TMAO, the MAO enzyme was partly involved in the transformation of the TMA in brain, which further supplemented the choline-TMA-TMAO pathway. Based on the above metabolic pathway, using multi-omics approaches, such as microbiodiversity, metagenomics and lipidomics, it was demonstrated that the reduction of plasma TMAO levels by gypenosides did not act on FMO3 and MAO in the pathway, but remodeled the microbiota and affected the trimethylamine lyase needed in the conversion of choline to TMA in intestinal flora. At the same time, gypenosides interfered with enzymes associated with TCA and lipid metabolism, thus affecting TMAO and lipid metabolism. Considering the bidirectional transformation of phosphatidycholine and choline, lipid metabolism and TMAO metabolism could affected each other to some extent. In conclusion, our study revealed the intrinsic correlation between long-term application of gypenosides to lipid reduction and nervous system protection, and explained why gypenosides were used to treat brain diseases, even though they had a poor ability to enter the brain. Besides, it provided a theoretical basis for clinical application of gypenosides and the development of new drugs.

Mechanism of gypenosides of Gynostemma pentaphyllum inducing apoptosis of renal cell carcinoma by PI3K/AKT/mTOR pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Gynostemma pentaphyllum (Thunb.) Makino is a traditional medicine commonly used in China, East Asia and Southeast Asia. In clinic, it is mainly used for hyperlipidemia and antitumor. Its antitumor activity was first recorded in "Illustrated Catalogue of Plants". Gypenosides were the main active ingredients of G. pentaphyllum. The anticancer activity of gypenosides in vivo and in vitro had been widely reported. However, the mechanism of gypenosides in renal cell carcinoma (RCC) still unclear.

AIM OF THE STUDY

In this study, we tried to investigate the active constituents from G. pentaphyllum and potential mechanisms in RCC treatment through network pharmacology and in vitro experiments.

MATERIAL/METHODS

Active compounds and their targets were evaluated and screened through TCMSP and Swiss Target Prediction database. Notably, nine preliminary screened components obtained from database were identified by LC-MS and LC-MS/MS. The targets associated with RCC were obtained from OMIM, TTD and GeneCards database. The PPI network and active component/target/pathway networks were constructed to identify the potential drug targets using String database and Cytoscape software. The functions and pathways of targets were analyzed through DAVID database. Finally, AutoDockTools 1.5.6 was used for molecular docking to assess the binding ability between compounds and targets. To support our prediction, we then explore the antitumor effect and mechanism of gypenosides by vitro experiments. CCK8 and flow cytometry were performed to evaluate cell death treated with gypenosides. Quantitative real-time PCR and Western blot were conducted to detect the changes of PI3K/AKT/mTOR signaling pathway.

RESULTS

Nine saponins and 68 targets have been screened. The hub targets covered PIK3CA, VEGFA, STAT3, JAK2, CCND1 and MAPK3. Enrichment analysis showed that the pathways mainly contained PI3K/Akt/mTOR, HIF-1, TNF, JAK-STAT and MAPK signaling pathways. Gypenosides extracted from G. pentaphyllum showed strong activity against 786-O and Caki-1 cells, and cell apoptosis were detected through Annexin V/PI dual staining assay. RT-qPCR showed that gypenosides downregulated the levels of PIK3CA, Akt and mTOR in Caki-1 and 786-O cells. Mechanistically, gypenosides induced apoptosis of RCC cells through regulating PI3K/Akt/mTOR signaling pathway which was implemented though decreasing the phosphorylation level of Akt and mTOR.

CONCLUSIONS

Gypenosides induced apoptosis of RCC cells by modulating PI3K/Akt/mTOR signaling pathway.

Co-administration of berberine/gypenosides/bifendate ameliorates metabolic disturbance but not memory impairment in type 2 diabetic mice

Cognitive impairment is a well-known complication of Type 2 diabetes mellitus (T2DM) characterized by cellular insulin resistance, chronic inflammation, and metabolic disturbances. Berberine, gypenosides and bifendate are traditional Chinese herbal medicines with multiple pharmacological activities including anti-inflammation, anti-oxidant, metabolism improvement and memory improvement. To investigate whether they have synergistic effect on T2DM metabolic syndrome and associated memory impairment, we measured in this study the effect of a low dose of berberine/gypenosides/bifendate (BGB) co-administration on metabolism and memory performance of T2DM model mice. We found that BGB co-administration ameliorated metabolic abnormalities of both high-fat diet/streptozotocin (STZ)-induced T2DM mice and db/db mice. However, it did not alleviate memory impairment in either type of T2DM model mice. Since neither berberine, gypenosides nor bifendate alone at the low dose is effective, we presume that BGB co-administration has synergistic action on T2DM metabolic syndrome. In addition, our findings suggest that higher doses of BGB might be required to ameliorate memory impairment than metabolic disturbance associated with T2DM.

Gypenosides improves nonalcoholic fatty liver disease induced by high-fat diet induced through regulating LPS/TLR4 signaling pathway

Background The contents of lipopolysaccharide (LPS) and Toll-like receptor 4 (TLR4) are significantly increased during the progression of nonalcoholic fatty liver disease (NAFLD). The study investigated the role of the LPS/TLR4 signaling pathway in improving gypenosides (Gyp) on NAFLD. Methods NAFLD model were established in rats and treated by Gyp. Pathological changes of liver tissues were observed by Hematoxylin and Eosin (HE) staining. Lipid metabolism and insulin resistance were measured. Expressions of inflammatory factors and protein of LPS/TLR4 downstream pathway were detected by qRT-PCR and Western blotting. THLE-2 cells were treated by free-fatty acid (FFA), Gyp, and LPS, and then transfected with TLR4. Next, cell viability was detected by MTT. Lipid droplet deposition and Triglyceride (TG) content were determined by Oil Red O staining and ELISA. Results Gyp protected fatty liver tissues in NAFLD model, and significantly reversed cholesterol increased by high-fat diet. Moreover, Gyp increased SOD content and decreased the contents of AST, ALT, MDA, HSI, FBG, FINS, HOMA-IR, IL-1β, and TNF-α, and promoted the expressions of TLR4, LPS, MyD88, p-IκBα, and reduced the expressions of p-p65 and IκBα in the NAFLD model. Gyp treatment significantly reduced lipid droplet deposition, increased TG content and MyD88, p-IκBα, p-p65 in FFA-induced liver cells, but LPS and TLR4 greatly reversed improvement of FFA by Gyp. Conclusion Gypenosides could improve liver function, lipid metabolism, insulin resistance, and levels of inflammatory factors in NAFLD model by regulating LPS/TLR4 signaling pathway in vitro and in vivo.

Quantification of computational fluid dynamics simulation assists the evaluation of protection by Gypenosides in a zebrafish pain model

In recent years, due to its rapid reproduction rate and the similarity of its genetic structure to that of human, the zebrafish has been widely used as a pain model to study chemical influences on behavior. Swimming behaviors are mediated by motoneurons in the spinal cord that drive muscle contractions, therefore a knowledge of internal muscle mechanics can assist the understanding of the effects of drugs on swimming activity. To demonstrate that the technique used in our study can supplement biological observations by quantifying the contribution of muscle effects to altered swimming behaviours, we have evaluated the pain/damage caused by 0.1% acetic acid to the muscle of 5 dpf zebrafish larvae and the effect of protection from this pain/damage with the saponin Gypenosides (GYP) extracted from Gynostemma pentaphyllum. We have quantified the parameters related to muscle such as muscle power and the resultant hydrodynamic force, proving that GYP could alleviate the detrimental effect of acetic acid on zebrafish larvae, in the form of alleviation from swimming debility, and that the muscle status could be quantified to represent the degree of muscle damage due to the acetic acid and the recovery due to GYP. We have also linked the behavioral changes to alteration of antioxidant and inflammation gene expression. The above results provide novel insights into the reasons for pain-related behavioral changes in fish larvae, especially from an internal muscle perspective, and have quantified these changes to help understand the protection of swimming behaviors and internal muscle by GYP from acetic acid-induced damage.

Gypenosides attenuate retinal degeneration in a zebrafish retinitis pigmentosa model

Retinitis pigmentosa (RP) is a collection of heterogenous genetic retinal disorders resulting in cumulative retinal deterioration involving progressive loss of photoreceptors and eventually in total blindness. Oxidative stress plays a central role in this photoreceptor loss. Gypenosides (Gyp) are the main functional component isolated from the climbing vine Gynostemma pentaphyllum and have been shown to defend cells against the effects of oxidative stress and inflammation, providing protection in experimentally-induced optic neuritis. The zebrafish model has been used to investigate a range of human diseases. Previously we reported early retinal degeneration in a mutant zebrafish line carrying a point-nonsense mutation in the retinitis pigmentosa GTPase regulator interacting protein 1 (rpgrip1) gene that is mutated in RP patients. The current study investigated the potential protective effects of Gyp against photoreceptor degeneration in the Rpgrip1 deleted zebrafish. Rpgrip1 mutant zebrafish were treated with 5 μg/ml of Gyp in E3 medium from 6 h post fertilization (hpf) till 1 month post fertilization (mpf). Rpgrip1 mutant zebrafish treated with 5 μg/ml of Gyp showed a significant decrease by 68.41% (p = 0.0002) in photoreceptor cell death compared to that of untreated mutant zebrafish. Expression of antioxidant genes catalase, sod1, sod2, gpx1, gclm, nqo-1 and nrf-2 was significantly decreased in rpgrip1 mutant zebrafish eyes by 61.51%, 77.40%, 60.11%, 81.17%, 72.07%, 78.95% and 85.42% (all p < 0.0001), respectively, when compared to that of wildtype zebrafish; superoxide dismutase and catalase activities, and glutathione levels in rpgrip1 mutant zebrafish eyes were significantly decreased by 87.21%, 21.55% and 96.51% (all p < 0.0001), respectively. There were marked increases in the production of reactive oxygen species (ROS) and malondialdehyde (MDA) by 2738.73% and 510.69% (all p < 0.0001), respectively, in rpgrip1 mutant zebrafish eyes; expression of pro-inflammatory cytokines IL-1β, IL-6 and TNF-α was also significantly increased by 150.11%, 267.79% and 190.72% (all p < 0.0001), respectively, in rpgrip1 mutant zebrafish eyes, compared to that of wildtype zebrafish. Treatment with Gyp significantly counteracted these effects. This study indicates that Gyp has a potential role in the treatment of RP.

Transcriptome-wide analysis of the AP2/ERF transcription factor gene family involved in the regulation of gypenoside biosynthesis in Gynostemma pentaphyllum

Gynostemma pentaphyllum is a traditional Chinese medicinal herb, serving as natural source of gypenosides (triterpene saponins). The APETALA2/ethylene response factor (AP2/ERF) transcription factors, playing essential regulation roles in plant biotic and abiotic stress responses and secondary metabolism biosynthesis. However, the regulation roles of AP2/ERF transcription factors in gypenosides biosynthesis in G. pentaphyllum remains little understood. In the present study, 125 AP2/ERF genes were identified from G. pentaphyllum transcriptome datasets. Phylogenetic, conserved motifs and expression pattern were employed to comprehensively analyze the 125 GpAP2/ERF genes. Based on the sequence similarity and phylogeny tree, the 125 GpAP2/ERF genes can be classified into 10 groups. Moreover, the distribution of conserved motifs among GpAP2/ERF proteins in phylogenetic trees was consistent with previous studies, thus supporting the classification. Expression profiling indicated that the 125 GpAP2/ERF genes exhibited distinct tissue-specific expression patterns. As confirmed by qRT-PCR, the four candidate GpAP2/ERF genes and gypenoside biosynthetic genes were highly expressed in leaves and/or flowers, and show similar expression patterns in response to MeJA. Base on the expression patterns and phylogenetic relationships, two GpAP2/ERF genes were considered as potential regulatory genes for gypenoside biosynthesis. Our study enhances understanding roles of GpAP2/ERF genes in regulation of gypenosides biosynthesis.

Gypenosides regulate farnesoid X receptor-mediated bile acid and lipid metabolism in a mouse model of non-alcoholic steatohepatitis

Background

Gypenosides (Gyp) are the main ingredient of the Chinese medicine, Gynostemma pentaphyllum. They are widely used in Asia as a hepatoprotective agent. Here, we elucidated the mechanism of Gyp in non-alcoholic steatohepatitis (NASH) with a focus on farnesoid X receptor (FXR)-mediated bile acid and lipid metabolic pathways.

Methods

NASH was induced in mice by high-fat diet (HFD) feeding, while mice in the control group were given a normal diet. At the end of week 10, HFD-fed mice were randomly divided into HFD, HFD plus Gyp, and HFD plus obeticholic acid (OCA, FXR agonist) groups and were given the corresponding treatments for 4 weeks. Next, we analyzed the histopathological changes as well as the liver triglyceride (TG) level and serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), fasting blood glucose (FBG), fasting insulin (FINS), TG, total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) levels as well as the bile acid profile. We carried out RT-PCR and western blotting to detect HFD-induced alterations in gene/protein expression related to bile acid and lipid metabolism.

Results

The HFD group had histopathological signs of hepatic steatosis and vacuolar degeneration. The liver TG and serum ALT, AST, FBG, FINS, TC, and LDL-C levels as well as the total bile acid level were significantly higher in the HFD group than in the control group (P < 0.01). In addition, we observed significant changes in the expression of proteins involved in bile acid or lipid metabolism (P < 0.05). Upon treatment with Gyp or OCA, signs of hepatic steatosis and alterations in different biochemical parameters were significantly improved (P < 0.05). Further, HFD-induced alterations in the expression genes involved in bile acid and lipid metabolism, such as CYP7A1, BSEP, SREBP1, and FASN, were significantly alleviated.

Conclusions

Gyp can improve liver lipid and bile acid metabolism in a mouse model of NASH, and these effects may be related to activation of the FXR signaling pathway.

Gypenosides Prevent H2O2-Induced Retinal Ganglion Cell Apoptosis by Concurrently Suppressing the Neuronal Oxidative Stress and Inflammatory Response

Our previous study demonstrated that gypenosides (Gp) exert protective effects on retinal nerve fibers and axons in a mouse model of experimental autoimmune optic neuritis. However, the therapeutic mechanisms remain unclear. Thus, in this study, a model of oxidative damage in retinal ganglion cells (RGCs) was established to investigate the protective effect of Gp, and its possible influence on oxidative stress in RGCs. Treatment of cells with H₂O₂ induced RGC injury owing to the generation of intracellular reactive oxygen species (ROS). In addition, the activities of antioxidative enzymes decreased and the expression of inflammatory factors increased, resulting in an increase in cellular apoptosis. Gp helped RGCs to become resistant to oxidation damage by directly reducing the amount of ROS in cells and exerting protective effects against H₂O₂-induced apoptosis. Treatment with Gp also reduced the generation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and increased nuclear respiratory factor 2 (Nrf-2) levels so as to increase the levels of heme oxygenase-1 (HO-1) and glutathione peroxidase 1/2 (Gpx1/2), which can enhance antioxidation in RGCs. In conclusion, our data indicate that neuroprotection by Gp involves its antioxidation and anti-inflammation effects. Gp prevents apoptosis through a mitochondrial apoptotic pathway. This finding might provide novel insights into understanding the mechanism of the neuroprotective effects of gypenosides in the treatment of optic neuritis.

Hybrid sequencing of the Gynostemma pentaphyllum transcriptome provides new insights into gypenoside biosynthesis

Background

Gypenosides are a group of triterpene saponins from Gynostemma pentaphyllum that are the same as or very similar to ginsenosides from the Panax species. Several enzymes involved in ginsenoside biosynthesis have been characterized, which provide important clues for elucidating the gypenoside biosynthetic pathway. We suppose that gypenosides and ginsenosides may have a similar biosynthetic mechanism and that the corresponding enzymes in the two pathways may have considerable similarity in their sequences. To further understand gypenoside biosynthesis, we sequenced the G. pentaphyllum transcriptome with a hybrid sequencing-based strategy and then determined the candidate genes involved in this pathway using phylogenetic tree construction and gene expression analysis.

Results

Following the PacBio standard analysis pipeline, 66,046 polished consensus sequences were obtained, while Illumina data were assembled into 140,601 unigenes with Trinity software. Then, these output sequences from the two analytical routes were merged. After removing redundant data with CD-HIT software, a total of 140,157 final unigenes were obtained. After functional annotation, five 2,3-oxidosqualene cyclase genes, 145 cytochrome P450 genes and 254 UDP-glycosyltransferase genes were selected for the screening of genes involved in gypenoside biosynthesis. Using phylogenetic analysis, several genes were divided into the same subfamilies or closely related evolutionary branches with characterized enzymes involved in ginsenoside biosynthesis. Using real-time PCR technology, their expression patterns were investigated in different tissues and at different times after methyl jasmonate induction. Since the genes in the same biosynthetic pathway are generally coexpressed, we speculated that GpOSC1, GpCYP89, and GpUGT35 were the leading candidates for gypenoside biosynthesis. In addition, six GpWRKYs and one GpbHLH might play a possible role in regulating gypenoside biosynthesis.

Conclusions

We developed a hybrid sequencing strategy to obtain longer length transcriptomes with increased accuracy, which will greatly contribute to downstream gene screening and characterization, thus improving our ability to elucidate secondary metabolite biosynthetic pathways. With this strategy, we found several candidate genes that may be involved in gypenoside biosynthesis, which laid an important foundation for the elucidation of this biosynthetic pathway, thus greatly contributing to further research in metabolic regulation, synthetic biology and molecular breeding in this species.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-6000-y) contains supplementary material, which is available to authorized users.

The components data of fuzheng huayu extracts, cordyceps sinensis mycelia polysaccharide, gypenosides and amygdalin

Fuzheng Huayu (FZHY) capsule is a traditional Chinese medicine composed of six Chinese medicinal herbs Tian et al. [1] and approved by China food and drug administration for liver fibrosis treatment [2], [3] Liu et al., 2009 and Liu et al., 2005. CGA formula consisting of Cordyeps sinensis polysaccharide (CS-PS), gypenosides (G), and amygdalin (A), are derived from FZHY formula. It is necessary to identify the chemical profile of FZHY and CGA formula to describe the mechanisms and the corresponding components of anti-fibrosis. It is showed that FZHY contains adenosine (5.21 mg/g), amygdalin (5.31 mg/g), salvianolic acid b (18.22 mg/g) and deoxyschizandrin (2.62 mg/g), respectively. CS-PS contained 60.5 ± 2.2% total carbohydrate, including 14.17% arabinose, 25.35% glucose and 60.48% galactose. Gypenosides contain 10.34% gypenosides XLIX and 16.58% gypenosides A. These data provide the primary chemical profile of FZHY and CGA formula and an example for components analysis of traditional Chinese medicine.

Gypenosides reverses depressive behavior via inhibiting hippocampal neuroinflammation

Gypenosides, a saponins extract isolated from the Gynostemma pentaphyllum plant, produces neuroprotective effects in the brain. Our previous studies have shown that hippocampal glucocorticoid receptor (GR)-brain-derived neurotrophic factor (BDNF)-TrkB signaling was involved in the antidepressant-like effects of gypenosides. It remains unknown whether gypenosides could alleviate neuroinflammation in depressive-like animals. The aim of the present study was to address this issue in chronic unpredictable mild stress (CUMS). Gypenosides was administrated for four weeks, followed by sucrose preference test and tail suspension test, which were performed to evaluate the effects of gypenosides. The results showed that gypenosides reversed both the decreased sucrose preference and increased immobility time in CUMS mice. In addition, gypenosides also attenuated the increase of pro-inflammatory cytokine levels in the hippocampus of CUMS animals. Furthermore, the activation of NF-κB, as well as its upstream mediators IKKα and IKKβ were inhibited by gypenosides. Last but not the least, CUMS promoted the activation of microglia, while gypenosides suppressed it according to the reduced number of iba1 positive cells. In conclusion, this study demonstrates that gypenosides exhibits the antidepressant-like effects in mice, which may be mediated by the inhibition of microglia and NF-κB signaling in the hippocampus.

Anti-atherosclerotic effect of Fermentum Rubrum and Gynostemma pentaphyllum mixture in high-fat emulsion- and vitamin D3-induced atherosclerotic rats

BACKGROUND

The mixture of Hongqu and gypenosides (HG) is composed of Fermentum Rubrum (Hongqu, in Chinese) and total saponins of Gynostemma pentaphyllum (Thunb.) Makino (Jiaogulan, in Chinese) in a 3.6:1 weight ratio. Both Hongqu and Jiaogulan are considered valuable traditional Chinese medicines (TCMs); they have been commonly used in China for the treatment of hyperlipidemia and related diseases for centuries. The aim of the current study was assess the anti-atherosclerotic effect of HG.

METHODS

Sixty-four Wistar rats were randomly divided into eight groups: normal, model, positive control (simvastatin, 1 mg/kg), Hongqu-treated (72 mg/kg), gypenoside (total saponin)-treated (20 mg/kg), and three doses HG-treated (50, 100, and 200 mg/kg). All of the rats were fed a basal diet. Additionally, the model group rats were intragastrically administered a high-fat emulsion and intraperitoneally injected with vitamin D₃. The serum lipid profiles, oxidative stress, inflammatory cytokine, and hepatic antioxidant levels were then determined. Furthermore, the liver histopathology and arterial tissue were analyzed, and the expression of hyperlipidemia- and atherosclerosis (AS)-related genes was measured using reverse transcription-polymerase chain reaction.

RESULTS

The AS rat model was established after 80 days. Compared to the model group, the HG-treated groups showed an obvious improvement in the serum lipid profiles, oxidative stress, and inflammatory cytokine levels, and showed markedly increased hepatic total antioxidant capacity. Moreover, the expression of genes related to lipid synthesis and inflammation reduced and that of the genes related to lipid oxidation increased in the liver and arterial tissue, which also reflected an improved health condition.

CONCLUSION

the anti-atherosclerotic effects of HG were superior to those of simvastatin, Hongqu, and the gypenosides. Therefore, HG may be a useful anti-atherosclerotic TCM preparation.

Gypenosides as natural emulsifiers for oil-in-water nanoemulsions loaded with astaxanthin: Insights of formulation, stability and release properties

The formulation, physicochemical stability and bioaccessibility of astaxanthin (AST) loaded oil-in-water nanoemulsions fabricated using gypenosides (GPs) as natural emulsifiers was investigated and compared with a synthetic emulsifier (Tween 20) that is commonly applied in food industry. GPs were capable of producing nanoemulsions with a small volume mean diameter (d_4,3 = 125 ± 2 nm), which was similar to those prepared using Tween 20 (d_4,3 = 145 ± 6 nm) under the same high-pressure homogenization conditions. GPs-stabilized nanoemulsions were stable against droplet growth over a range of pH (6-8) and thermal treatments (60-120 °C). Conversely, instability occurred under acidic (pH 3-5) and high ionic strength (25-100 mM CaCl₂) conditions. In comparison with Tween 20, GPs were more effective at inhibiting AST from degradation during 30 days of storage at both 5 and 25 °C. However, GPs led to lower lipid digestion and AST bioaccessibility from nanoemulsions than did Tween 20.

miR-124 antagonizes the antidepressant-like effects of standardized gypenosides in mice

Our previous study demonstrated that gypenosides produced antidepressant-like effects in mice exposed to chronic mild stress in a brain-derived neurotrophic factor-dependent manner. However, whether other mechanisms are involved in the antidepressant-like effects of gypenosides is not clear. miR-124 is one of the most abundant microRNAs in the hippocampus, and its dysregulation is related to the pathophysiology of depression. The glucocorticoid receptor is dysfunctional in depression, and it is a direct target of miR-124. Therefore, the present study used corticosterone-induced mice as a model to evaluate the role of miR-124 on the antidepressant-like effects of gypenosides. miR-124 agomir was intracerebrally injected prior to administration of gypenosides and corticosterone injection. Sucrose preference and forced swimming tests were performed 21 days later. Proteins related to glucocorticoid receptors and brain-derived neurotrophic factor-tyrosine receptor kinase B signaling in the hippocampus were evaluated. Our results demonstrated that gypenosides reversed the chronic corticosterone injection-induced decreased sucrose preference and increased immobility time. In contrast, this effect was antagonized by miR-124 injection. In addition, gypenosides increased glucocorticoid receptor and tyrosine receptor kinase B expression in the hippocampus, which activated brain-derived neurotrophic factor signaling. miR-124 also blocked these effects. In conclusion, this study demonstrated that a reduction in miR-124 was required for the antidepressant-like effects of gypenosides induced by chronic corticosterone injection in mice.

Gypenosides ameliorate memory deficits in MPTP-lesioned mouse model of Parkinson's disease treated with L-DOPA

Background

Previous studies have revealed that gypenosides (GPS) improve the symptoms of anxiety disorders in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned rat model of Parkinson’s disease (PD). The present study aimed to investigate the effects of GPS on memory deficits in an MPTP-lesioned mouse model of PD treated with L-3,4-dihydroxyphenylalanine (L-DOPA).

Methods

MPTP (30 mg/kg/day, 5 days)-lesioned mice were treated with GPS (50 mg/kg) and/or L-DOPA (10 and 25 mg/kg) for 21 days. After the final treatments, behavioral changes were assessed in all mice using passive avoidance and elevated plus-maze tests. We then evaluated the biochemical influences of GPS treatment on levels of tyrosine hydroxylase (TH), dopamine, N-methyl-D-aspartate (NMDA) receptors, extracellular signal-regulated kinase (ERK1/2), and cyclic AMP-response element binding protein (CREB) phosphorylation.

Results

MPTP-lesioned mice exhibited deficits associated with habit learning and spatial memory, which were further aggravated by treatment with L-DOPA (25 mg/kg). However, treatment with GPS (50 mg/kg) ameliorated memory deficits. Treatment with GPS (50 mg/kg) also improved L-DOPA (25 mg/kg)-treated MPTP lesion-induced decreases in retention latency on the passive avoidance test, as well as levels of TH-immunopositive cells and dopamine in the substantia nigra and striatum. GPS treatment also attenuated increases in retention transfer latency on the elevated plus-maze test and in NMDA receptor expression, as well as decreases in the phosphorylation of ERK1/2 and CREB in the hippocampus. Treatment with L-DOPA (10 mg/kg) also ameliorated deficits in habit learning and spatial memory in MPTP-lesioned mice, and this effect was further enhanced by treatment with GPS (50 mg/kg).

Conclusion

GPS ameliorate deficits in habit learning and spatial memory by modulating the dopaminergic neuronal and N-methyl-D-aspartate receptor-mediated signaling systems in MPTP-lesioned mice treated with L-DOPA. GPS may serve as an adjuvant therapeutic agent for memory deficits in patients with PD receiving L-DOPA.

Mechanism underlying protective effect of gypenosides against type 2 diabetes mellitus and nonalcoholic fatty liver disease in rats

AIM

To explore the mechanism underlying protective effect of gypenosides (GPS) against type 2 diabetes mellitus and nonalcoholic fatty liver disease (T2DM-NAFLD) in rats.

METHODS

Sixty rats were randomly divided into five groups: blank control group, T2DM-NAFLD model group, low dose GPS group, medium dose GPS group, and high dose GPS group. The efficacy was confirmed by histopathology, and the expression of tumor necrosis factor-α (TNF-α) and nuclear factor-κB (NF-κB) in the liver was analyzed by immunohistochemistry. In addition, the expression of peroxisome proliferator activated receptor gamma (PPARγ) and cytochrome P4501A1 (CYP4501A1) mRNAs was detected by RT-PCR.

RESULTS

Immunohistochemical study showed that the expression of TNF-α and NF-κB was significantly reduced by GPS, in a dose-dependent manner. The expression of PPARγ and CYP4501A1 mRNAs measured by RT-PCR was also significantly down-regulated by GPS. Moreover, GPS decreased the infiltration of liver fats and reversed the histopathological changes in a dose-dependent manner.

CONCLUSION

GPS protects against T2DM-NAFLD by down-regulating the expression of TNF-α, NF-κB, PPARγ and CYP4501A1.

Antidepressant-like effects of standardized gypenosides: involvement of brain-derived neurotrophic factor signaling in hippocampus

RATIONALE

Gypenosides have been reported to produce neuroprotective effects and increase monoamine neurotransmitter levels in the brain.

OBJECTIVE

Considering that depression is involved in monoamine reduction, this study evaluated the antidepressant-like effects of gypenosides in mice exposed to chronic unpredictable mild stress (CUMS).

METHODS

The sucrose preference test and forced swimming test were performed after administration of gypenosides (at 25, 50, or 100 mg/kg) for 4 weeks. Hippocampal brain-derived neurotrophic factor (BDNF) and its downstream targets were analyzed by western blot. Additionally, hippocampal neuronal proliferation was measured by immunohistochemistry.

RESULTS

Four-week treatment with fluoxetine (20 mg/kg) and gypenosides (at either 50 or 100 mg/kg) increased sucrose preference and decreased the immobility time in mice exposed to CUMS. In addition, gypenosides (at either 50 or 100 mg/kg) also increased BDNF expression and neuronal proliferation in the hippocampus of CUMS animals. Further, we showed that treating CUMS mice with K252a, which is an inhibitor of the BDNF receptor TrkB, blocked the effects of gypenosides (100 mg/kg), including behavioral improvements, neuronal proliferation, and up-regulation of p-TrkB, p-ERK, and p-Akt proteins.

CONCLUSIONS

This study demonstrates that gypenosides exhibit antidepressant-like effects in mice, which may be mediated by activation of the BDNF-ERK/Akt signaling pathway in the hippocampus.

Gypenosides alleviate myocardial ischemia-reperfusion injury via attenuation of oxidative stress and preservation of mitochondrial function in rat heart

Gypenosides (GP) are the predominant components of Gynostemma pentaphyllum, a Chinese herb medicine that has been widely used for the treatment of chronic inflammation, hyperlipidemia, and cardiovascular disease. GP has been demonstrated to exert protective effects on the liver and brain against ischemia-reperfusion (I/R) injury, yet whether it is beneficial to the heart during myocardial I/R is unclear. In this study, we demonstrate that pre-treatment with GP dose-dependently limits infarct size, alleviates I/R-induced pathological changes in the myocardium, and preserves left ventricular function in a rat model of cardiac I/R injury. In addition, GP pre-treatment reduces oxidative stress and protects the intracellular antioxidant machinery in the myocardium. Further, we show that the cardioprotective effect of GP is associated with the preservation of mitochondrial function in the cardiomyocytes, as indicated by ATP level, enzymatic activities of complex I, II, and IV on the mitochondrial respiration chain, and the activity of citrate synthase in the citric acid cycle for energy generation. Moreover, GP maintains mitochondrial membrane integrity and inhibits the release of cytochrome c from the mitochondria to the cytosol. The cytoprotective effect of GP is further confirmed in vitro in H9c2 cardiomyoblast cell line with oxygen-glucose deprivation and reperfusion (OGD/R), and the results indicate that GP protects cell viability, reduces oxidative stress, and preserves mitochondrial function. In conclusion, our study suggests that GP may be of clinical value in cytoprotection during acute myocardial infarction and reperfusion.

Mechanism of action of gypenosides on type 2 diabetes and non-alcoholic fatty liver disease in rats

AIM: To explore the mechanism of action of gypenosides (GPs) on type 2 diabetes mellitus and non-alcoholic fatty liver disease (T2DM-NAFLD) in rats.

METHODS: Sixty rats were randomly divided into a healthy group, an untreated disease model group and GP-treatment groups. The study involved the evaluation of biochemical parameters, including serum aspartate transaminase (AST), alanine transferase (ALT), blood glucose (BG), triglycerides (TG) and total cholesterol (TC). Additionally, the protective effect of the treatments were confirmed histopathologically and the expression of TNF-α and NF-κB in the rat liver was analyzed using immunohistochemistry. The expression of proliferator-activated receptor gamma (PPARγ) and cytochrome P₄₅₀ (CYP₄₅₀) 1A1 mRNA was determined by quantitative RT-PCR.

RESULTS: GP treatments at oral doses of 200, 400, and 800 mg/kg per day significantly decreased the levels of serum AST and ALT (P < 0.05, P < 0.01), especially at the dose of 800 mg/kg per day. To a similar extent, GP at 800 mg/kg per day reduced the levels of BG (4.19 ± 0.47, P < 0.01), TG (80.08 ± 10.05, P < 0.01), TC (134.38 ± 16.39, P < 0.01) and serum insulin (42.01 ± 5.04, P < 0.01). The expression of TNF-α and NF-κB measured by immunohistochemistry was significantly reduced by GPs in a dose-dependent manner, and the expression of PPARγ and CYP₄₅₀1A1 mRNA, as measured using quantitative real-time PCR, were significantly down-regulated by GPs. Moreover, GPs decreased the infiltration of liver fats and reversed the histopathological changes in a dose-dependent manner.

CONCLUSION: This study suggests that GPs have a protective effect against T2DM-NAFLD by down-regulating the expression of TNF-α and NF-κB proteins, and PPARγ and CYP₄₅₀1A1 mRNAs.

Gypenosides pre-treatment protects the brain against cerebral ischemia and increases neural stem cells/progenitors in the subventricular zone

Gypenosides (GPs) have been reported to have neuroprotective effects in addition to other bioactivities. The protective activity of GPs during stroke and their effects on neural stem cells (NSCs) in the ischemic brain have not been fully elucidated. Here, we test the effects of GPs during stroke and on the NSCs within the subventricular zone (SVZ) of middle cerebral artery occlusion (MCAO) rats. Our results show that pre-treatment with GPs can reduce infarct volume and improve motor function following MCAO. Pre-treatment with GPs significantly increased the number of BrdU-positive cells in the ipsilateral and contralateral SVZ of MCAO rats. The proliferating cells in both sides of the SVZ were glial fibrillary acidic protein (GFAP)/nestin-positive type B cells and doublecortin (DCX)/nestin-positive type A cells. Our data indicate that GPs have neuroprotective effects during stroke which might be mediated through the enhancement of neurogenesis within the SVZ. These findings provide new evidence for a potential therapy involving GPs for the treatment of stroke.