Four new dammarane-type triterpenes derivatives from hydrolyzate of total Gynostemma pentaphyllum saponins and their bioactivities

Gypenoside XLIX alleviates acute liver injury: Emphasis on NF-κB/PPAR-α/NLRP3 pathways

Liver is one of the vital organs in the human body and liver injury will have a very serious impact on human damage. Gypenoside XLIX is a PPAR-α activator that inhibits the activation of the NF-κB signaling pathway. The components of XLIX have pharmacological effects such as cardiovascular protection, antihypoxia, anti-tumor and anti-aging. In this study, we used cecum ligation and puncture (CLP) was used to induce in vivo mice hepatic injury, and lipopolysaccharide (LPS)-induced inflammation in RAW264.7 cells, evaluated whether Gypenoside XLIX could have a palliative effect on sepsis-induced acute liver injury via NF-κB/PPAR-α/NLRP3. In order to gain insight into these mechanisms, six groups were created in vivo: the Contol group, the Sham group, the CLP group, the CLP + XLIX group (40 mg/kg) and the Sham + XLIX (40 mg/kg) group, and the CLP + DEX (2 mg/kg) group. Three groups were created in vitro: Control, LPS, LPS + XLIX (40 μM). The analytical methods used included H&E staining, qPCR, reactive oxygen species (ROS), oil red O staining, and Western Blot. The results showed that XLIX attenuated hepatic inflammatory injury in mice with toxic liver disease through inhibition of the TLR4-mediated NF-κB pathway, attenuated lipid accumulation through activation of PPAR-α, and attenuated hepatic pyroptosis by inhibiting NLRP3 production. Regarding the imbalance between oxidative and antioxidant defenses due to septic liver injury, XLIX reduced liver oxidative stress-related biomarkers (ALT, AST), reduced ROS accumulation, decreased the amount of malondialdehyde (MDA) produced by lipid peroxidation, and increased the levels of antioxidant enzymes such as glutathione (GSH) and catalase (CAT). Our results demonstrate that XLIX can indeed attenuate septic liver injury. This is extremely important for future studies on XLIX and sepsis, and provides a potential pathway for the treatment of acute liver injury.

Recent Advances in Research on Active Compounds Against Hepatic Fibrosis

BACKGROUND

Almost all chronic liver diseases cause fibrosis, which can lead to cirrhosis and eventually liver cancer. Liver fibrosis is now considered to be a reversible pathophysiological process and suppression of fibrosis is necessary to prevent liver cancer. At present, no specific drugs have been found that have hepatic anti-fibrotic activity.

OBJECTIVE

The research progress of anti-hepatic fibrosis compounds in recent ten years was reviewed to provide a reference for the design and development of anti-hepatic fibrosis drugs.

METHODS

According to the structure of the compounds, they are divided into monocyclic compounds, fused-heterocyclic compounds, and acyclic compounds.

RESULTS

In this article, the natural products and synthetic compounds with anti-fibrotic activity in recent ten years were reviewed, with emphasis on their pharmacological activity and structure-activity relationship (SAR).

CONCLUSION

Most of these compounds are natural active products and their derivatives, and there are few researches on synthetic compounds and SAR studies on natural product.

Gypenoside-14 Reduces Depression via Downregulation of the Nuclear Factor Kappa B (NF-kB) Signaling Pathway on the Lipopolysaccharide (LPS)-Induced Depression Model

Neuroinflammation is a common pathogenetic sign of depression and is closely linked to the development of depression. Many clinical anti-inflammatory drugs act as antidepressants by reducing the neuroinflammatory response. Previous research found that gypenosides and their bioactive compound gypenoside-14 (GP-14) had neuroprotective effects against hypoxia-induced injury and reduced neuroinflammation-related high-altitude cerebral edema. Here we investigated the effects of GP-14 on the lipopolysaccharide (LPS)-induced depression-like behavior model. LPS (0.5 mg/kg) was injected into mice intraperitoneally for 7 consecutive days to induce depression-like behavior, which is considered a model for the exacerbation of depression. GP-14 in the amount of 100 mg/kg was simultaneously administered by gavage for 7 days. In the LPS-induced depression model, GP-14 not only attenuated depression-like behavior but also improved the anxiety-like behavior of the mice. Additionally, GP-14 treatment mitigated learning and cognitive decline in depressed mice. ELISA and immunofluorescence staining results revealed that GP-14 inhibited the upregulation of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6), and suppressed the activation of astrocytes induced with LPS, indicating its potent anti-inflammatory effect. GP-14 pretreatment in C8 cells and primary astrocytes can inhibit the activation of the NF-κB signaling pathway and downregulate the levels of pro-inflammatory factors. In summary, our findings showed that GP-14 had significant anti-inflammation and anti-depression properties; thus, GP-14 could be a promising lead compound for treating depression.

Dammarane-type saponins from Gynostemma pentaphyllum and their cytotoxicities

Heat-processed Gynostemma pentaphyllum has shown strong activity against human lung carcinoma A549 cells. In this study, two dammarane-type saponins together with two known compounds were isolated from the ethanol extract of the heat-processed leaves of G. pentaphyllum. They were identified as 2α,3β,12β-trihydroxydammar-20(22),24-diene-3-O-β-D-glucopyranoside (1, namely damulin E), 2α,3β,12β-trihydroxydammar-20,24-diene-3-O-β-D-glucopyranoside (2, namely damulin F), damulin A (3) and damulin B (4), respectively, using NMR and mass spectra. Damulin E and damulin F showed moderate activity against A549, H1299, T24, SH-SY5Y and K562 cell lines in vitro using CCK-8 assay.

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.

Triterpenoids from the genus Gynostemma: Chemistry and pharmacological activities

ETHNOPHARMACOLOGICAL RELEVANCE

G. pentaphyllum, also known as Jiao-Gu-Lan, has been used traditionally as folk remedies for many diseases, including diabetes mellitus, metabolic syndrome, aging, and neurodegenerative diseases in China and some countries in East and Southeast Asia. It is considered as an "immortality herb" in Guizhou Province, because it was consumed regularly by the elderly native inhabitants. Other species of the same genus Gynostemma such as G. longipes and G. laxum have been used as alternatives to G. pentaphyllum in ethno-medicine in Vietnam and other Asian countries.

AIM OF THE REVIEW

The review aims to summarize up-to-date study results on Gynostemma species, including traditional usage, phytochemical profile, pharmacological activities, and toxicological studies, in order to suggest future research orientation and therapeutic applications on acute and chronic diseases.

MATERIALS AND METHODS

The relevant literature on the genus Gynostemma was gathered from secondary databases (Web of Science and PubMed), books, and official websites. The latest literature cited in this review was published in February 2020.

RESULTS

The genus Gynostemma has been widely used in traditional medicine, mainly for treatment of diabetes, hypertension, obesity, and hepatosteatosis. To date, 328 dammarane-type saponins were isolated and structurally elucidated from Gynostemma species. Crude extracts, saponin-rich fractions (gypenosides), and pure compounds were reported to show a wide range of pharmacological activities in both in vitro and in vivo experiments. The most notable pharmacological effects were anti-cancer, cardioprotective, hepatoprotective, neuroprotective, anti-diabetic, anti-obesity, and anti-inflammatory activities. Toxicological studies were conducted only on G. pentaphyllum, showing that the plant extracts were relatively safe in both acute and long-term toxicity experiments at the given dosage while no toxicological studies were reported for the other species.

CONCLUSIONS

The review summarizes current studies on traditional uses, phytochemistry, biological properties, and toxicology of medicinal Gynostemma species. Till now, the majority of publications still focused only on G. pentaphyllum. However, the promising preliminary data of other Gynostemma species indicated the research potential of this genus, both in phytochemical and pharmacological aspects. Furthermore, clinical data are required to evaluate the efficacy and undesired effects of crude extracts, standard saponin fractions, and pure compounds prepared from Gynostemma medicinal plants.

Amelioration of hepatic steatosis is associated with modulation of gut microbiota and suppression of hepatic miR-34a in Gynostemma pentaphylla (Thunb.) Makino treated mice

Background

Non-alcoholic fatty liver disease (NAFLD) is a chronic and progressive liver disease with an increased risk of morbidity and mortality. However, so far no specific pharmacotherapy has been approved. Gynostemma pentaphylla (Thunb.) Makino (GP) is a traditional Chinese medicine that is widely used against hyperlipemia as well as hyperglycemia. This study aims to evaluate the effect of GP on NAFLD and explore the possible mechanism.

Methods

High-fat-diet induced NAFLD mice model were orally administrated with GP at dose of 11.7 g/kg or equivalent volume of distilled water once a day for 16 weeks. Body weight, food intake and energy expenditure were assessed to evaluate the general condition of mice. The triglycerides, total cholesterol content in the liver and liver histopathology, serum lipid profile and serum insulin level, fecal microbiome, hepatic microRNAs and relative target genes were analyzed.

Results

Mice in GP treatment group displayed improved hepatic triglycerides content with lower lipid droplet in hepatocyte and NAFLD activity score. Besides, GP treatment altered the composition of gut microbiota and the relative abundance of some of the key components that are implicated in metabolic disorders, especially phylum Firmicutes (Eubacterium, Blautia, Clostridium and Lactobacillus). Several hepatic microRNAs were downregulated by GP treatment such as miR-130a, miR-34a, miR-29a, miR-199a, among which the expression miR-34a was altered by more than four-fold compared to that of HFD group (3:14). The correlation analysis showed that miR-34a was strongly related to the change of gut microbiota especially phylum Firmicutes (R = 0.796). Additionally, the target genes of miR-34a (HNF4α, PPARα and PPARα) were restored by GP both in mRNA and protein levels.

Conclusion

Our results suggested that GP modulated the gut microbiota and suppressed hepatic miR-34a, which was associated with the amelioration of hepatic steatosis.

Comparison of the Effects and Inhibitory Pathways of the Constituents from Gynostemma pentaphyllum against LPS-Induced Inflammatory Response

Saponins, the primary phytochemicals contributing to the health properties of G. pentaphyllum were frequently studied. However, compounds responsible for its bioactivities were still poorly understood. The saponin-rich fraction (GPMS), 3- O-[2G-( E)-Coumaroyl-3G- O-β-d-glucosyl-3R- O-β-d-glucosylrutinoside] (KCGG), gypenoside XLVI and gypenoside L were obtained by purification of G. pentaphyllum. The compounds were examined and compared with GPMS for their inhibitory effects on LPS-induced nitric oxide (NO) production. GPMS and KCGG differed in their inhibitory capacities against pro-inflammatory cytokines secretion. GPMS exhibited strong inhibition on inducible nitric oxide synthase (iNOS) and interleukin-6 (IL-6) mRNA expression but weak inhibition on tumor necrosis factor-α (TNF-α) and interleukin-1β mRNA expression. KCGG was better at inhibiting iNOS, IL-6, TNF-α, and cyclooxygenase-2 (COX-2) mRNA expression. GPMS showed similar inhibitory potency on mitogen-activated protein kinase phosphorylation and nuclear factor-κB (NF-κB) activation, as evidenced by their regulatory effects on LPS-induced P65 phosphorylation, NF-κB nuclear translocation, IκBα phosphorylation and degradation, IκKα/β phosphorylation, c-Jun N-terminal kinase phosphorylation, P38 phosphorylation, and COX-2 expression. KCGG was more powerful in inhibiting the NF-κB pathway, suggesting that KCGG might be used in the management of inflammatory-associated diseases in which NF-κB played pivotal roles. Furthermore, KCGG might be mainly responsible for the predominant effects of GPMS.