Dammarane-type saponins from Gynostemma pentaphyllum

Dammarane-type triterpenoids from Gynostemma compressum X. X. Chen & D. R. Liang (Cucurbitaceae) and their AMPK activation effect in 3T3-L1 cells

Bioassay-guided fractionation of the 80% ethanol extract of Gynostemma compressum X. X. Chen & D. R. Liang (Cucurbitaceae) resulted in the isolation and identification of eight undescribed triterpenoids, gycomol VN1, gycomol VN2, and gycomosides VN1-6 from the bioactive n-butanol fraction. The structures of these compounds were elucidated by one- and two-dimensional nuclear magnetic resonance spectroscopy, high-resolution electrospray ionisation mass spectrometry, and chemical methods. All isolated compounds were evaluated for their 5'-adenosine monophosphate-activated protein kinase (AMPK) and acetyl-coenzyme A carboxylase (ACC) activation effects on 3T3-L1 cells. Importantly, gycomol VN2, gycomoside VN1, and gycomosides VN3-5 activated the phosphorylation of AMPK and its downstream substrate ACC in 3T3-L1 cells at a dose of 10 μM. These effects imply that the activation of AMPK and ACC by active compounds from G. compressum has considerable potential for the prevention of obesity and its related disorders by activating AMPK signaling pathways.

Integrated Metabolomic and Transcriptomic Analysis and Identification of Dammarenediol-II Synthase Involved in Saponin Biosynthesis in Gynostemma longipes

Gynostemma longipes contains an abundance of dammarane-type ginsenosides and gypenosides that exhibit extensive pharmacological activities. Increasing attention has been paid to the elucidation of cytochrome P450 monooxygenases (CYPs) and UDP-dependent glycosyltransferases (UGTs) that participate downstream of ginsenoside biosynthesis in the Panax genus. However, information on oxidosqualene cyclases (OSCs), the upstream genes responsible for the biosynthesis of different skeletons of ginsenoside and gypenosides, is rarely reported. Here, an integrative study of the metabolome and the transcriptome in the leaf, stolon, and rattan was conducted and the function of GlOSC1 was demonstrated. In total, 46 triterpenes were detected and found to be highly abundant in the stolon, whereas gene expression analysis indicated that the upstream OSC genes responsible for saponin skeleton biosynthesis were highly expressed in the leaf. These findings indicated that the saponin skeletons were mainly biosynthesized in the leaf by OSCs, and subsequently transferred to the stolon via CYPs and UGTs biosynthesis to form various ginsenoside and gypenosides. Additionally, a new dammarane-II synthase (DDS), GlOSC1, was identified by bioinformatics analysis, yeast expression assay, and enzyme assays. The results of the liquid chromatography-mass spectrometry (LC-MS) analysis proved that GlOSC1 could catalyze 2,3-oxidosqualene to form dammarenediol-II via cyclization. This work uncovered the biosynthetic mechanism of dammarenediol-II, an important starting substrate for ginsenoside and gypenosides biosynthesis, and may achieve the increased yield of valuable ginsenosides and gypenosides produced under excess substrate in a yeast cell factory through synthetic biology strategy.

Natural Products Targeting Liver X Receptors or Farnesoid X Receptor

Nuclear receptors (NRs) are a superfamily of transcription factors induced by ligands and also function as integrators of hormonal and nutritional signals. Among NRs, the liver X receptors (LXRs) and farnesoid X receptor (FXR) have been of significance as targets for the treatment of metabolic syndrome-related diseases. In recent years, natural products targeting LXRs and FXR have received remarkable interests as a valuable source of novel ligands encompassing diverse chemical structures and bioactive properties. This review aims to survey natural products, originating from terrestrial plants and microorganisms, marine organisms, and marine-derived microorganisms, which could influence LXRs and FXR. In the recent two decades (2000-2020), 261 natural products were discovered from natural resources such as LXRs/FXR modulators, 109 agonists and 38 antagonists targeting LXRs, and 72 agonists and 55 antagonists targeting FXR. The docking evaluation of desired natural products targeted LXRs/FXR is finally discussed. This comprehensive overview will provide a reference for future study of novel LXRs and FXR agonists and antagonists to target human diseases, and attract an increasing number of professional scholars majoring in pharmacy and biology with more in-depth discussion.

ComMSnDB-An Automatable Strategy to Identify Compounds from MS Data Sets (Identification of Gypenosides as an Example)

Gynostemma pentaphyllum (Thunb.) Makino is a popular functional food and is also used as an important medicinal plant in China. Gypenoside, the main active constituent in G. pentaphyllum (Thunb.) Makino, belongs to dammarane-type triterpenoid saponins. Due to its high molecular weight and high polarity, it is difficult to obtain complete compound information for gypenoside extracts via mass spectrometry experiments. In this study, an automated targeted data postprocessing strategy called Compound MSⁿ Database (ComMSⁿDB) was designed and established to elucidate compounds in gypenoside extracts based on ultrahigh-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC-ESI-Q-TOF-MS/MS). As a result, 18 types of and 199 main saponin constituents, including 47 potential novel compounds, were tentatively identified from different habitats. At the same time, 15 gypenoside standard compounds were used to verify the feasibility of the ComMSⁿDB strategy. These results demonstrated that ComMSⁿDB offers practical value for quick, automated, and effective compound identification.

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.

Ten New Dammarane-Type Saponins with Hypolipidemia Activity from a Functional Herbal Tea-Gynostemma pentaphyllum

Gynostemma pentaphyllum (thumb.) Makino is a functional herbal tea commonly used in Asian countries and regions to reduce blood lipid levels. G. pentaphyllum saponin is the main component, but there are still a large number of components with lipid-lowering activity that have not been found. In this study, 10 novel dammarane-type saponins, (1-10) and a known one (11) were isolated from G. pentaphyllum. Ten new compounds were identified and named as yunnangypenosides A-J (1-10), and another known one (11) was also obtained. Their chemical structures were determined by MS, NMR spectroscopic analyses. Moreover, the cytotoxicities on human HepG-2 hepatocellular carcinoma cells of these isolates were evaluated, and the results showed that compounds 1-11 had no obvious cytotoxicity. Finally, all these compounds were evaluated for their lipid-lowering effect by means of the oil red O staining method. Ten compounds could significantly reduce lipid levels except of 2, especially 8 exhibite the strongest hypolipidemia activity.

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

Three novel dammarane-type saponins, 2α,3β,12β,20(S),24(S)-pentahydroxydammar-25-ene-3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-20-O-β-D-glucopyranoside (1, namely gypenoside J1), 2α,3β,12β,20(S),25-pentahydroxydammar-23-ene-3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-20-O-β-D-glucopyranoside (2, namely gypenoside J2) and 2α,3β,12β,20(S)-tetrahydroxydammar-25-en-24-one-3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-20-O-β-D-xylopyranosyl-(1→6)-β-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.

New dammarane-type triterpenoid glycosides from Gynostemma burmanicum

The chemical composition of Gynostemma burmanicum King ex Chakrav. was investigated for the first time in this study. Nine dammarane glycosides (1‒9) were isolated from the EtOH extract of the aerial parts of G. burmanicum. Their structures were elucidated by 1D and 2D NMR spectroscopic interpretation as well as by chemical studies. The new compounds were 3β,20S-dihydroxydammar-24-ene-3-O-β-D-glucopyranosyl-20-O-[β-D-xylopyranosyl-(1→6)-β-D-glucopyranoside] (1), 3β,12β,20S-trihydroxydammar-24-ene-3-O-β-D-xylopyranosyl-20-O-[β-D-xylopyranosyl-(1→6)-β-D-glucopyranoside] (2), and 12-oxo-3β,20S-dihydroxydammar-24-ene-3-O-[β-D-glucopyranosyl(1→2)-β-D-glucopyranosyl]-20-O-[β-D-xylopyranosyl-(1→6)-β-D-glucopyranoside] (3).

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.

New Dammarane-type Saponins from Gynostemma pentaphyllum

Six new dammarane-type saponins, gypenosides CP1-6 (16), along with 19 known compounds 7⁻25, were isolated and characterized from the aerial parts of Gynostemma pentaphyllum. Among these compounds, eight dammarane-type saponins, 2, 5, 6, 7, 11, 12, 13, and 15, exhibited the greatest antiproliferative effects against two human tumor cell lines (A549 and HepG2).

Profiling and activity screening of Dammarane-type triterpen saponins from Gynostemma pentaphyllum with glucose-dependent insulin secretory activity

The global prevalence of type 2 diabetes is increasing rapidly; consequently there is great need for new and novel therapeutic options. Gynostemma pentaphyllum (GP) is a traditional medicinal plant, mainly present in Southeast Asian countries, that has been reported to exert antidiabetic effects, by stimulating insulin secretion. The specific compound responsible for this effect is however as yet unidentified. Screening for discovery and identification of bioactive compounds of an herbal GP extract, was performed in isolated pancreatic islets from spontaneously diabetic Goto-Kakizaki (GK) rats, a model of type 2 diabetes, and from non-diabetic control Wistar rats. From this herbal extract 27 dammarane-type saponins, including two novel compounds, were isolated and their structure was elucidated by mass spectrometry and NMR spectroscopy. One of the dammarane-type triterpenoid showed a glucose-dependent insulin secretion activity. This compound, gylongiposide I, displays unique abilities to stimulate insulin release at high glucose levels (16.7 mM), but limited effects at a low glucose concentration (3.3 mM). Further studies on this compound, also in vivo, are warranted with the aim of developing a novel anti-diabetic therapeutic with glucose-dependent insulinogenic effect.

Saponins as modulators of nuclear receptors

As plant-derived natural products, saponins have been widely applied for the dietary modification of metabolic syndrome. However, the underlying mechanisms of their preventive and therapeutic effects are still largely unclear. Nuclear receptors have been identified as potential pharmaceutical targets for treating various types of metabolic disorders. With similar structure to endogenous hormones, several saponins may serve as selective ligands for nuclear receptors. Recently, a series of saponins are proved to exert their physiological activities through binding to nuclear receptors. This review summarizes the biological and pharmacological activities of typical saponins mediated by some of the most well described nuclear receptors, including the classical steroid hormone receptors (ER, GR, MR, and AR) and the adopted orphan receptors (PPAR, LXR, FXR, and PXR).

Cytotoxic triterpenes from the acid hydrolyzate of Gynostemma pentaphyllum saponins

One new dammarane-type triterpene, gypsapogenin A (1), was isolated from the acid hydrolyzate of total saponins from Gynostemma pentaphyllum (Thunb.) Makino, together with two known compounds, (20S,24S)-3β,20,21β,23β,25-pentahydroxy-21,24-cyclodammarane (2) and (23S)-3β-hydroxydammar-20,24-dien-21-oic acid 21,23-lactone (3). Its structural elucidations were accomplished mainly on the basis of the interpretation of spectroscopic data, such as IR, HR-TOF-MS, and NMR. The cytotoxic activities were evaluated against HepG2 and A549 human cancer cell lines.

Transcriptome Sequencing of Gynostemma pentaphyllum to Identify Genes and Enzymes Involved in Triterpenoid Biosynthesis

G. pentaphyllum (Gynostemma pentaphyllum), a creeping herbaceous perennial with many important medicinal properties, is widely distributed in Asia. Gypenosides (triterpenoid saponins), the main effective components of G. pentaphyllum, are well studied. FPS (farnesyl pyrophosphate synthase), SS (squalene synthase), and SE (squalene epoxidase) are the main enzymes involved in the synthesis of triterpenoid saponins. Considering the important medicinal functions of G. pentaphyllum, it is necessary to investigate the transcriptomic information of G. pentaphyllum to facilitate future studies of transcriptional regulation. After sequencing G. pentaphyllum, we obtained 50,654,708 unigenes. Next, we used RPKM (reads per kilobases per million reads) to calculate expression of the unigenes and we performed comparison of our data to that contained in five common databases to annotate different aspects of the unigenes. Finally, we noticed that FPS, SS, and SE showed differential expression of enzymes in DESeq. Leaves showed the highest expression of FPS, SS, and SE relative to the other two tissues. Our research provides transcriptomic information of G. pentaphyllum in its natural environment and we found consistency in unigene expression, enzymes expression (FPS, SS, and SE), and the distribution of gypenosides content in G. pentaphyllum. Our results will enable future related studies of G. pentaphyllum.

Antimalarial Properties of Aqueous Crude Extracts of Gynostemma pentaphyllum and Moringa oleifera Leaves in Combination with Artesunate in Plasmodium berghei-Infected Mice

Due to the emergence and spread of malaria parasite with resistance to antimalarial drugs, discovery and development of new, safe, and affordable antimalarial are urgently needed. In this respect, medicinal plant extracts are targets to optimize antimalarial actions and restore efficacy of standard antimalarial drugs. The present study was aimed at determining the antimalarial activities of Gynostemma pentaphyllum and Moringa oleifera leaf extracts in combination with artesunate against Plasmodium berghei-infected mice. P. berghei ANKA maintained by serial passage in ICR mice were used based on intraperitoneal injection of 1 × 10⁷ parasitized erythrocytes and subsequent development of parasitemia. These infected mice were used to investigate the antimalarial activity of artesunate (6 mg/kg) in combination with 500, 1,000, and 2,000 mg/kg of G. pentaphyllum and M. oleifera leaf extracts using 4-day suppressive test. It was found that these extracts showed significant (P < 0.05) antimalarial activity in dose-dependent manner with percentage of suppression of 45, 50, and 55% for G. pentaphyllum leaf extract and 35, 40, and 50% for M. oleifera leaf extract. Additionally, artesunate combined with these extracts presented higher antimalarial activity, compared to extract treated alone with percentage of suppression of 78, 91, and 96% for G. pentaphyllum leaf extract and 73, 82, and 91% for M. oleifera leaf extract. The results indicated that combination treatment of G. pentaphyllum or M. oleifera leaf extracts with artesunate was able to increase the antimalarial activity by using low dose of artesunate. Hence, these results justified the combination of these extracts and artesunate in antimalarial herbal remedies.

Anti-cancer effects of Gynostemma pentaphyllum (Thunb.) Makino (Jiaogulan)

Gynostemma pentaphyllum (Thunb.) Makino (GpM) (Jiaogulan) has been widely used in Chinese medicine for the treatment of several diseases, including hepatitis, diabetes and cardiovascular disease. Furthermore, GpM has recently been shown to exhibit potent anti-cancer activities. In this review, we have summarized recent research progress on the anti-cancer activities and mechanisms of action of GpM, as well as determining the material basis for the anti-cancer effects of GpM by searching the PubMed, Web of Science and China National Knowledge Infrastructure databases. The content of this review is based on studies reported in the literature pertaining to the chemical components or anti-cancer effects of GpM up until the beginning of August, 2016. This search of the literature revealed that more than 230 compounds have been isolated from GpM, and that most of these compounds (189) were saponins, which are also known as gypenosides. All of the remaining compounds were classified as sterols, flavonoids or polysaccharides. Various extracts and fractions of GpM, as well as numerous pure compounds isolated from this herb exhibited inhibitory activity towards the proliferation of cancer cells in vitro and in vivo. Furthermore, the results of several clinical studies have shown that GpM formula could have potential curative effects on cancer. Multiple mechanisms of action have been proposed regarding the anti-cancer activities of GpM, including cell cycle arrest, apoptosis, inhibition of invasion and metastasis, inhibition of glycolysis and immunomodulating activities.

In Vitro Anticancer Activity of a Nonpolar Fraction from Gynostemma pentaphyllum (Thunb.) Makino

Gynostemma pentaphyllum (Thunb.) Makino (GpM) has been widely used in traditional Chinese medicine (TCM) for the treatment of various diseases including cancer. Most previous studies have focused primarily on polar fractions of GpM for anticancer activities. In this study, a nonpolar fraction EA1.3A from GpM showed potent growth inhibitory activities against four cancer cell lines with IC50 ranging from 31.62 μg/mL to 38.02 μg/mL. Furthermore, EA1.3A also inhibited the growth of breast cancer cell MDA-MB-453 time-dependently, as well as its colony formation ability. EA1.3A induced apoptosis on MDA-MB-453 cells both dose-dependently and time-dependently as analyzed by flow cytometry and verified by western blotting analysis of apoptosis marker cleaved nuclear poly(ADP-ribose) polymerase (cPARP). Additionally, EA1.3A induced cell cycle arrest in G0/G1 phase. Chemical components analysis of EA1.3A by GC-MS revealed that this nonpolar fraction from GpM contains 10 compounds including four alkaloids, three organic esters, two terpenes, and one catechol substance, and all these compounds have not been reported in GpM. In summary, the nonpolar fraction EA1.3A from GpM inhibited cancer cell growth through induction of apoptosis and regulation of cell cycle progression. Our study shed light on new chemical bases for the anticancer activities of GpM and feasibilities to develop new anticancer agents from this widely used medicinal plant.

Damarane-type Saponins from Gynostemma Longipes and their Cytotoxic Activity

Two new damarane- type saponins, named gylongiposides II-III (1 and 2), along with one known compound, (23 S)-3β,20ζ,21ζ-trihydroxy-19-oxo-21,23-epoxydammar-24-ene 3- O-α-L-rhamnopyranosyl-(1→2)-[β-D-xylopyranosyl-(1→3)]-α-L-arabinopyranoside, were isolated from the leaves of Gynostemma longipes C.Y.Wu. Their structures were determined by 1D- and 2D-NMR and HR-ESI-MS spectra. Compounds 1–3 exhibited moderate activity against four human cancer cell lines, A-549, HT-29, OVCAR, and MCF-7, with IC50 values ranging from 9.8 ± 2.1 to 49.6 ± 2.6 μM.

Oleanane-type saponins from Glochidion glomerulatum and their cytotoxic activities

Eight oleanane-type saponins, glomerulosides A-H, were isolated from leaves of Glochidion glomerulatum. All isolated compounds were evaluated for cytotoxic activity on four human cancer cell lines, A-549, HT-29, OVCAR, and MCF-7. Glomerulosides C and E, which contain a benzoyloxy group at C-22, showed significant cytotoxic activities against the A-549, HT-29, and OVCAR cancer cell lines with IC50 values ranging from 5.9 to 9.8μM. Glomeruloside A showed cytotoxicity on HT-29 and OVCAR cell lines with IC50 values of 7.3 and 6.6μM, respectively. Moreover, glomeruloside B exhibited significant activity on A-549 and HT-29 cancer cell lines with IC50 values of 9.7 and 7.5μM. In contrast, glomerulosides F-H, lacking a benzoyloxy group, showed only moderate cytotoxic activity.

Isolation and Characterization of Dammarane-Type Saponins from Gynostemma pentaphyllum and Their Inhibitory Effects on IL-6-Induced STAT3 Activation

Five new dammarane-type saponins, gypenosides GD1-GD5 (1-5), along with six known saponins (6-11), were isolated from the aerial parts of Gynostemma pentaphyllum using various chromatographic methods. Their structures were elucidated by a combination of spectroscopic and spectrometric data, including 1D and 2D NMR and HRESIMS. All isolates were tested for their inhibitory effects on IL-6-induced STAT3 promoter activity in Hep3B cells. Compounds 1, 9, and 11 displayed potent inhibitory effects, with IC50 values ranging from 0.27 to 0.59 μM.

Novel dammarane saponins from Gynostemma pentaphyllum and their cytotoxic activities against HepG2 cells

Two new dammarane saponins, 2α,3β,12β-trihydroxydammar-20(22),24-diene-3-O-[β-D-glucopyranoxyl(1→2)-β-D-6″-O-acetylglucopyranoside (1, namely damulin C) and 2α,3β,12β-trihydroxydammar-20(21),24-diene-3-O-[β-D-glucopyranoxyl(1→2)-β-D-6″-O-acetylglucopyranoside (2, namely damulin D), were isolated from the ethanol extract of Gynostemma pentaphyllum, which had been heat processed by steaming at 125 °C. The NMR spectroscopic data of the novel saponins were completely assigned by using a combination of 2D NMR experiments including (1)H-(1)H COSY, HSQC, and HMBC. Their cytotoxic activities of human liver adenocarcinoma HepG2 cells were evaluated in vitro. They showed cytotoxicities against HepG2 cell line with IC50 of 40±0.7 and 38±0.5 μg/ml, respectively.

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.

Four new triterpenoid glycosides from the seed residue of Hippophae rhamnoides subsp. sinensis

Four new triterpenoid saponins (1-4) were isolated from the seed residue of Hippophae rhamnoides subsp. sinensis, named 3-O-[β-D-glucopyranosyl(1 → 2)-β-D-glucopyranosyl-(1 → 3)]-[α-L-rhamnopyranosyl-(1 → 2)]-α-L-arabinopyranosyl-13-ene-19-one-28-oic acid 28-O-β-D-glucopyranosyl ester (1), 3-O-[β-D-glucopyranosyl(1 → 2)-β-D-glucopyranosyl-(1 → 3)]-[α-L-rhamnopyranosyl-(1 → 2)]-α-L-arabinopyranosyl-13-ene-19-one-30-hydroxyolean-28-oic acid 28-O-β-D-glucopyranosyl ester (2), 3-O-[β-D-glucopyranosyl(1 → 2)-β-D-glucopyranosyl-(1 → 3)]-[α-L-rhamnopyranosyl-(1 → 2)]-β-D-glucopyranosyl-13-ene-19-one-28-oic acid 28-O-β-D-glucopyranosyl ester (3), and 3-O-[β-D-glucopyranosyl(1 → 2)-β-D-glucopyranosyl-(1 → 3)]-[α-L-rhamnopyranosyl-(1 → 2)]-β-D-glucopyranosyl-13-ene-19-one-30-hydroxyolean-28-oic acid 28-O-β-D-glucopyranosyl ester (4), and their structures were elucidated on the basis of spectroscopic and chemical methods.

Toxicity evaluation of standardized extract of Gynostemma pentaphyllum Makino

ETHNOPHARMACOLOGICAL RELEVANCE

To evaluate the safety of standardized extract of Gynostemma pentaphyllum in rats.

MATERIALS AND METHODS

The water extract of Gynostemma pentaphyllum was prepared and standardized, the dry powder yielded 6% gypenosides. In the acute oral toxicity test, the single oral dose of 5000 mg/kg of Gynostemma pentaphyllum extract was given to female Sprague-Dawley rats. In subchronic toxicity test, the oral dose of 1000 mg/kg/day of the extract was given to rats in treatment and satellite groups for 90 days. Satellite groups of both sexes were kept for additional 28 days after 90-day treatment. Control rats received distilled water.

RESULTS

Standardized extract of Gynostemma pentaphyllum did not cause death or any toxic signs in rats. The daily administration of the extract for 90 days did not produce lethal or harmful effects. Although certain hematological and blood chemistry values (i.e., neutrophil, monocyte, glucose, and serum alkaline phosphatase levels) were found to be statistically different from the control group, however; these values were within the ranges of normal rats.

CONCLUSION

Standardized extract of Gynostemma pentaphyllum did not produce mortality or any abnormality in rats.

Dammarane glycosides from the root of Machilus yaoshansis

Nine new dammarane triterpene glycosides (1-3 and 8-13) and 12 known analogues have been isolated from an ethanol extract of the roots of Machilus yaoshansis. Compounds 1-7 have an uncommon 20,23-dihydroxydammar-24-en-21-oic acid-21,23-lactone moiety that was previously reported in compounds isolated from Gynostemma pentaphyllum. The configurations of the lactone moieties in 1-3 were determined by comparison of the experimental ECD spectra of 1-3 and the hydrolysates, 1a and 1b, with the corresponding calculated ECD spectra. On the basis of NMR and ECD data analysis of 1-7, the previously reported C-20 and C-23 configurations of 4-7 and related derivatives from Gynostemma pentaphyllum were revised. In addition, the application of NMR data and Cotton effects to the determination of the relative and absolute configurations of the γ-lactone moiety in 3β,20,23-trihydroxydammar-24-en-21-oic acid-21,23-lactone derivatives is discussed.

Triterpenoids

This review covers the isolation and structure determination of triterpenoids, including squalene derivatives, protostanes, lanostanes, holostanes, cycloartanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes and saponins; 305 references are cited.

Dammarane-type saponins from Gynostemma pentaphyllum

Seven dammarane glycosides, gypenosides GC1 to GC7, together with ten known compounds, gypenosides V, XIV, XLII-XLVI, gynosaponins TN-1, -2, and gymnemaside VI, were isolated from the methanol extract of the aerial parts of Gynostemma pentaphyllum. Their structures were elucidated by both analysis of 1D and 2D NMR spectra and chemical degradation.