[A novel dammarane-type saponin from Gynostemma pentaphyllum and its neuroprotective effect].

One new and two known dammarane-type saponins were isolated from the leaves of Gynostemma pentaphyllum using various chromatographic methods. Their structures were identified by HR-ESI-MS,~( 1)H-NMR, ~(13)C-NMR, 2 D-NMR spectra as 2α,3ß,12ß,20,24(S)-tetrahdroxydammar-25-en-3-O-[ß-D-glucopyranosyl(1→2)-ß-D-glucopyranosyl]-20-O-ß-D-xylopyranosyl(1→6)-ß-D-glucopyranoside(1, a new compound, namely gypenoside J5) and 2α,3ß,12ß,20,24(R)-tetrahdroxydammar-25-en-3-O-[ß-D-glucopyranosyl(1→2)-ß-D-glucopyranosyl]-20-O-ß-D-xylopyranosyl(1→6)-ß-D-glucopyranoside(2) and 2α,3ß,12ß,20-tetrahydroxy-25-hydroperoxy-dammar-23-en-3-O-[ß-D-glucopyranosyl(1→2)][ß-D-glucopyranosyl]-20-O-[ß-D-xylopyranosyl(1→6)]-ß-D-glucopy-ranoside(3), respectively. Compounds 1 and 2 were a pair of C-24 epimers. All compounds showed weak cytotoxicity agxinst H1299, HepG2, PC-3, SH-SY5 Y cancer cell lines. However, they exerted protective effect against SH-SY5 Y cellular damage induced by H_2O_2 dose-dependently, of which compound 1 displayed the strongest antioxidant effect. The present study suggested that G. pentaphyllum has antioxidative potential and the saponins from G. pentaphyllum are considered as the active compounds with neuroprotecitve effect.

Monomer gypenoside LI from Gynostemma pentaphyllum inhibits cell proliferation and upregulates expression of miR-128-3p in melanoma cells.

Gypenosides have anticancer activity against many cancers. Gypenoside LI is a gypenoside monomer from Gynostemma pentaphyllum, its pharmacological functions in melanoma have not been reported. In this study, we found that gypenoside LI had a potent cytotoxic effect on melanoma cells. Gypenoside LI can induce intrinsic apoptosis along with S phase arrest. Furthermore, gypenoside LI inhibited the colony formation ability of melanoma through inhibition of the Wnt/ß-catenin signaling pathway. Interestingly, we also found that gypenoside LI can induce the upregulation of the tumor suppressor miR-128-3p during melanoma apoptosis. In contrast, gypenoside LI induced apoptosis, cell cycle arrest, and inhibition of the Wnt/ß-catenin signaling pathway, which were abolished by overexpression of the miR-128-3p inhibitor in A375 cells. Taken together, these results showed that gypenoside LI could inhibit human melanoma cells through inducing apoptosis, arresting cell cycle at the S phase and suppressing the Wnt/ß-catenin signaling pathway in a miR-128-3p dependent manner.

Novel dammarane-type saponins from Gynostemma pentaphyllum and their neuroprotective effect.

Three novel dammarane-type saponins, 2α,3ß,12ß,20(S),24(S)-pentahydroxydammar-25-ene-3-O-ß-D-glucopyranosyl-(1→2)-ß-D-glucopyranosyl-20-O-ß-D-glucopyranoside (1, namely gypenoside J1), 2α,3ß,12ß,20(S),25-pentahydroxydammar-23-ene-3-O-ß-D-glucopyranosyl-(1→2)-ß-D-glucopyranosyl-20-O-ß-D-glucopyranoside (2, namely gypenoside J2) and 2α,3ß,12ß,20(S)-tetrahydroxydammar-25-en-24-one-3-O-ß-D-glucopyranosyl-(1→2)-ß-D-glucopyranosyl-20-O-ß-D-xylopyranosyl-(1→6)-ß-D-glucopyranoside (3, namely gypenoside J3) along with one known gypenoside (gypenoside LVII) were isolated from the aerial parts of G. pentaphyllum using various chromatographic methods. Their structures were elucidated on the basis of IR, 1D- (1H and 13C), 2D-NMR spectroscopy (HSQC, HMBC and COSY), and mass spectrometry (ESI-MS/MS). Their activity was tested using CCK-8 assay. These four compounds showed little anti-cancer activity with IC50 values more than 100 µM against four types of human cancer lines. The effects of them against H2O2-induced oxidative stress in human neuroblastoma SH-SY5Y cells were evaluated and they all showed potential neuroprotective effects with 3.64-18.16% higher cell viability than the H2O2-induced model group.

[Protective effects of flavonoids from Gynostemma pentaphyllum on oxidative damage in LLC-PK1 cells].

Four flavonoids were isolated from Gynostemma pentaphyllum by chromatography methods and their structures were identified by MS and NMR spectra data as quercetin-3-O-( 2″,6″-di-α-L-rhamnosyl)-ß-D-galactopyranoside( 1),quercetin-3-O-( 2″,6″-di-α-L-rhamnosyl)-ß-D-glucopyranoside( 2),quercetin-3-O-( 2″-α-L-rhamnosyl)-ß-D-galactopyranoside( 3),and quercetin-3-O-( 2″-α-L-rhamnosyl)-ß-D-glucopyranoside( 4). Among them,compounds 1-3 were obtained from the Cucurbitaceae family for the first time.The four flavonoids showed potent antioxidant effects against the DPPH,·OH and ■radicals in vitro,especially for DPPH radical scavenging activity with the IC50 values of 71. 4,29. 5,48. 3 and 79. 2 µmol·L~(-1),respectively. Moreover,the four flavonoids displayed strong cytoprotection against AAPH-induced oxidative damage in LLC-PK1 cells by suppressing the increase of malondialdehyde( MDA) and the decrease of the superoxide dismutase( SOD) and glutathione( GSH). Since further research is needed to prove its efficacy in vivo and clinical trial,the study may provide four potential antioxidants from G. pentaphyllum.

Inhibitory Effect of Damulin B from Gynostemma pentaphyllum on Human Lung Cancer Cells.

Damulin B, a dammarane-type saponin from steamed Gynostemma pentaphyllum, exhibits the strongest activity against human lung carcinoma A549 cells among the isolated active saponins. In this study, the structure-activity relationship of a series of saponin compounds was discussed. The inhibitory effect of damulin B on human lung cancer A549 and H1299 cells was investigated from apoptosis, cell cycle, and migration aspects. In vitro, human lung cancer cells were more susceptible to damulin B treatment than human normal fibroblasts. Damulin B exhibited a strong cytotoxic effect, as evidenced by the increase of apoptosis rate, reduction of mitochondrial membrane potential (MMP), generation of reactive oxygen species, and G0/G1 phase arrest. Furthermore, damulin B activated the following: both intrinsic and extrinsic apoptosis pathways along with early G1 phase arrest via the upregulation of the Bax, Bid, tBid, cleaved caspase-8, and p53 expression levels; downregulation of the procaspase-8/-9, CDK4, CDK6, and cyclin D1 expression levels; and more release of cytochrome c in the cytoplasm. In addition, antimigratory activities and suppressive effects on metastasis-related factors, such as MMP-2 and MMP-9, accompanied by the upregulation of IL-24 were revealed. Altogether, the results proved that damulin B could inhibit human lung cancer cells by inducing apoptosis, blocking the cell cycle at early G0/G1 phase and suppressing the migration. Hence, damulin B has potential therapeutic efficacy against lung cancer.

The inhibitory effect of gypenoside stereoisomers, gypenoside L and gypenoside LI, isolated from Gynostemma pentaphyllum on the growth of human lung cancer A549 cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Gypenosides are major constituents in Gynostemma pentaphyllum (Thunb.) Makino. Previous studies have shown that gypenosides isolated from G. pentaphyllum possess inhibitory effect on the growth of cancer cells, especially A549 cells, with structure-activity relationship (SAR). However, the underlying mechanism of gypenoside-induced A549 cell death remains to be clarified. AIM OF THE STUDY: To further investigate SAR and the underlying mechanism of gypenosides in A549 cells. MATERIALS AND METHODS: Gypenosides were isolated from G. pentaphyllum using chromatography methods and identified using MS and NMR data. The cytotoxicity was determined with CCK-8 assay. The effects of gypenosides on apoptosis, cell cycle and migration were investigated through cell morphology observation, flow cytometry analysis and key proteins detection. RESULTS: Three gypenosides, 2α,3ß,12ß,20(S)-tetrahydroxydammar-24-ene-3-O-ß-D-glucopyranoside-20-O-ß-D-glucopyranoside, gypenoside L and gypenoside LI were isolated from G. pentaphyllum. Gypenoside stereoisomers, gypenoside L (S configuration at C20) and gypenoside LI (R configuration at C20) showed stronger activity against A549 cells. Furthermore, both induced A549 cell apoptosis through intrinsic and extrinsic pathways evidenced by reducing mitochondrial membrane potential (MMP), generating reactive oxygen species (ROS), releasing more cytochrome c and down-regulating procaspase 8. However, gypenoside L blocked A549 cells in G0/G1, while gypenoside LI induced G2/M arrest, which was further verified by different expression of CDK1, CDK2 and CDK4. In addition, both inhibited A549 cell migration, which was evidenced by down-regulation of MMP-2/9 as well as scratch wound assay and transwell assay. CONCLUSION: C20 of gypenoside played an important role in A549 cell cytotoxicity and gypenoside stereoisomers could be used as potential multi-target chemopreventive agents for cancer.

A new dammarane-type saponin from Gynostemma pentaphyllum induces apoptosis in A549 human lung carcinoma cells.

Gynostemma pentaphyllum has been widely used as a traditional herb for its antioxidant and immunostimulatory activities. We have previously reported several useful dammarane-type saponins with cytotoxicity against A549 human lung cancer cells from heat-processed G. pentaphyllum. In this study, a new dammarane-type saponin, 20(S)-2α,3ß,12ß-tetrahydroxydammar-3-O-ß-d-glucopyranoside (namely gypenoside Jh1), was isolated from the ethanol extract of heat-processed G. pentaphyllum using column chromatography and semi-preparative HPLC. Gypenoside Jh1 exhibited strong cytotoxicity against A549 cells in a concentration-dependent manner, which was associated with apoptotic cell death characterized by morphological changes, Hoechst 33258 nuclear staining, Annexin V and propidium iodide binding and mitochondrial potentials assay. Quantitative analysis using flow cytometry also showed that the proportion of apoptotic cells was increased after gypenoside Jh1 treatment. These findings indicated that gypenoside Jh1 showed antiproliferative effects on A549 cells and mitochondrial-dependent pathway is involved in gypenoside Jh1-induced apoptosis.

Metabolite profiling of gypenoside LVI in rat after oral and intravenous administration.

Gypenoside LVI, one of the major bioactive triterpene saponins in Gynostemma pentaphyllum, has been regarded as a potential and promising lead drug for anti-tumor strategy. To better understand the pharmacological activities of the component, an investigation of its in vivo metabolism is important and necessary. In the present study, a liquid chromatography-ion trap time of flight tandem mass spectrometry has been utilized to discover and identify the metabolites of gypenoside LVI in rat urine after oral and intravenous administration. Negative electrospray ionisation mass spectrometry was used to discern gypenoside LVI and its possible metabolites in urine samples. As a result, after oral and intravenous administration, eight and six metabolites together with gypenoside LVI were detected and identified in rat urine, respectively. As metabolites of gypenoside LVI, they have never been reported before. Deglycosylation and dehydration were found to be the major metabolic processes of gypenoside LVI in rat.

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.

Cytotoxic activity of gypenosides and gynogenin against non-small cell lung carcinoma A549 cells.

The activity of gypenosides and gynogenin of Gynostemma pentaphyllum against non-small cell lung carcinoma (NSCLC) A549 cells was investigated to identify the structural characteristics of gypenosides and gynogenin to have anti-NSCLC activity. Of the tested dammarane-type compounds, 20S-dammar-24-en-2α,3ß,12ß,20-tetrol showed the strongest activity against A549 cells. Based on the structure and cytotoxic activity relationships of gypenosides and gynogenin, the OH group in C-2, the connected sugar number and the configuration in C-20 were important for cytotoxic activity against A549 cells.