Gentiopicroside improves non-alcoholic steatohepatitis by activating PPARα and suppressing HIF1

Gentiopicroside (GPS) is a highly water-soluble small-molecule drug and the main bioactive secoiridoid glycoside of Gentiana scabra that has been shown to have hepatoprotective effects against non-alcoholic steatohepatitis (NASH), a form of non-alcoholic fatty liver disease (NAFLD) that can progress to cirrhosis and hepatocellular carcinoma. However, the effects of GPS on NASH and the underlying mechanisms remain obscure. Firstly, a high-fat, high-cholesterol (HFHC) diet and a high-sugar solution containing d-fructose and d-glucose were used to establish a non-alcoholic steatohepatitis (NASH) mice model. Secondly, we confirmed GPS supplementation improve metabolic abnormalities and reduce inflammation in NASH mice induced by HFHC and high-sugar solution. Then we used metabolomics to investigate the mechanisms of GPS in NASH mice. Metabolomics analysis showed GPS may work through the Peroxisome Proliferator-Activated Receptor (PPAR) signaling pathway and glycine, serine, and threonine metabolism. Functional metabolites restored by GPS included serine, glycine, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Western blot and qRT-PCR analysis confirmed GPS improve NASH by regulating PPARα and Hypoxia-Inducible Factor-1α (HIF-1α) signaling pathways. In vitro, studies further demonstrated EPA and DHA enhance fatty acid oxidation through the PPARα pathway, while serine and glycine inhibit oxidative stress through the HIF-1α pathway in palmitic acid-stimulated HepG2 cells. Our results suggest GPS's anti-inflammatory and anti-steatosis effects in NASH progression are related to the suppression of HIF-1α through the restoration of L-serine and glycine and the activation of PPARα through increased EPA and DHA.

Gentiopicroside-An Insight into Its Pharmacological Significance and Future Perspectives

Gentiopicroside (GPS) is a leading component of several plant species from the Gentianaceae botanical family. As a compound with plenty of biological activities and a component of herbal drugs, GPS has an important role in the regulation of physiological processes in humans. The results of recently published scientific studies underline a meaningful role of this molecule as an active factor in metabolic pathways and mechanisms, which may have an influence in the treatment of different diseases, including digestive tract disorders, malignant changes, neurological disorders, microbial infections, bone formation disorders, inflammatory conditions, and others. This review aims to collect previously published reports on the biological properties of GPS as a single compound that were confirmed by in vitro and in vivo studies, and to draw attention to the newly discovered role of this bitter-tasting secoiridoid. Thanks to these properties, the research on this substance could be revisited.

Gentiopicroside ameliorates CCl4-induced liver injury in mice by regulating the PPAR-γ/Nrf2 and NF-κB/IκB signaling pathways

OBJECTIVE

This study explored the mechanisms by which gentiopicroside protects against carbon tetrachloride (CCl4)-induced liver injury.

METHODS

Male mice were randomly assigned to the control; CCl4; bifendate 100 mg/kg; or gentiopicroside 25, 50, or 100 mg/kg groups. Both vehicle and drugs were administered intragastrically for 7 days. Mice were administered CCl4 intraperitoneally 1 hour after the last drug dose. After 24 hours, we collected blood and liver samples for testing.

RESULTS

Gentiopicroside significantly reduced serum alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase activities with corresponding reductions in hepatocyte denaturation and necrosis. Gentiopicroside enhanced superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and glutathione levels and reduced heme oxygenase 1 (HO-1) activity and malondialdehyde levels in the liver, and these effects were attributed to peroxisome proliferator-activated receptor (PPAR)-γ/nuclear factor erythroid 2-related factor 2 (Nrf2) activation. Meanwhile, gentiopicroside significantly downregulated HO-1 and upregulated SOD and GSH-Px at the mRNA level in the liver. Furthermore, gentiopicroside significantly suppressed serum tumor necrosis factor-α and interleukin-1β secretion, which was associated with the inhibition of nuclear factor-kappa B (NF-κB)/inhibitor of NF-κB (IκB).

CONCLUSIONS

Gentiopicroside ameliorated CCl4-induced liver injury in mice via the PPAR-γ/Nrf2 and NF-κB/IκB pathways.

In vitro, ex vivo and clinical approaches to evaluate the potential effect of Gentiana lutea extract on skin

BACKGROUND

Dark circles affect subjects of all ages and in all skin types. They can be treated by various methods, particular by topical solutions. This investigation was directed towards exploring the effect of gentiopicroside (GP) on the skin around the eyes. For this, an extract of Gentiana lutea (GIE) containing GP (65% by dry matter) was evaluated on oxidant and angiogenesis parameters using in vitro and ex-vivo studies. A clinical experimentation was also realized.

METHODS

The effect of GIE at different concentrations on antioxidant gene was evaluated in vitro by RT-qPCR after treatment of NHDF. The effect of 2.93 μg mL-1 GIE on the release of VEGF-A and VEGF-C by NHDF was also studied. The effect of 87.9 μg mL-1 GIE was also evaluated on pseudotube formation in a coculture system of normal dermal microvascular endothelial cells (HMVEC-d)-NHDF stimulated or not with VEGF as pro-angiogenic factor. Prior to these assays, preliminary cytotoxicity assays were performed using a standard WST-8 reduction assay. The expressions of carboxymethyl-lysine and glyoxalase-1 were quantified on skin explants topically treated with 147 μg mL-1 GIE in basal and UVA-irradiated conditions. A clinical study was conducted in 22 subjects using topical twice daily for 14 days on eye area (split-face application: cream containing 147 μg mL-1 GIE versus placebo). 3D image acquisition and skin colour measurement were performed at D0 and D14.

RESULTS

Treatment of GIE upregulated the gene expression of NFE2L2 and downregulated the expression of CXCL8. GIE targeted AGEs pathways and reduced the formation of pseudotubes. A total of 147 μg mL-1 GIE gel cream significantly reduced significantly the average roughness and relief of the upper eyelid skin as well as the redness of dark circles after 14 days of application.

CONCLUSION

By acting on the pathway of AGEs, VEGF-A and VEFG-C, GIE seems to allow a rejuvenation of the skin resulting, among others, in a decrease in redness. It now would be interesting to evaluate the efficacy of GIE on skin around eyes microbiota, antibacterial gentiopicroside property being well-established.

Gentiopicroside modulates glucose homeostasis in high-fat-diet and streptozotocin-induced type 2 diabetic mice

Gluconeogenesis is closely related to the occurrence and development of type 2 diabetes mellitus (T2DM). Gentiopicroside (GPS) is the main active secoiridoid glycoside in Gentiana manshurica Kitagawa, which can improve chronic complications associated with diabetes and regulate glucose metabolism. However, the effects and potential mechanisms by which GPS affects T2DM understudied and poorly understood. In this study, we systematically explored the pharmacological effects of GPS on T2DM induced by a high-fat diet (HFD) and streptozotocin (STZ) as well as explored its related mechanisms. The results showed that GPS supplementation discernibly decreased blood glucose levels, food intake and water consumption, ameliorated glucose intolerance, abnormal pyruvate tolerance, insulin resistance and dyslipidemia. Furthermore, GPS discernibly ameliorated pathological morphological abnormalities of the liver and pancreas, reduced hepatic steatosis and maintain the balance between α-cells and β-cells in pancreas. Moreover, GPS significantly inhibited gluconeogenesis, as evidenced by the suppressed protein expression of phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase (G6Pase) in the liver. Additionally, the results of Western blot analysis revealed that GPS increased p-PI3K, p-AKT, and p-FOXO1 expression levels, and decreased FOXO1 expression at protein level in the liver. Furthermore, the results of the immunostaining and Western blot analysis demonstrated that GPS supplementation increased the expression of zonula occludens-1 (ZO-1) and occludin in the ileum. Collectively, these results indicate that GPS may inhibit hepatic gluconeogenesis by regulating the PI3K/AKT/FOXO1 signaling pathway and maintain intestinal barrier integrity, and ultimately improve T2DM. Together, these findings indicate that GPS is a potential candidate drug for the prevention and treatment of T2DM, and the results of our study will provide experimental basis for further exploration of the possibility of GPS as a therapeutic agent for T2DM.

Gentiopicroside Ameliorates Cerebrovascular Angiogenesis, Neuronal Injury and Immune Disorder in Rats with Cerebral Ischemia/Reperfusion Injury via VEGF and Phosphorylated Nrf2 Elevation

BACKGROUND

Cerebral ischemia-reperfusion (CI/R) injury is induction of blood flow restoration after an ischemic stroke. Gentiopicroside (GPC) is the principal active secoiridoid glycoside of Gentiana Manshurica Kitagawa. This research aimed to illuminate the function of GPC and its mechanism in CI/R injury.

METHODS

After CI/R injury models were constructed, GPC (25, 50 or 100 mg/kg) was then administered by gavage to rats. Rats were grouped into Sham, CI/R, CI/R+25 mg/kg GPC, CI/R+50 mg/kg GPC, and CI/R+100 mg/kg GPC. Neuronal cells were exposed to oxygen-glucose deprivation and reperfusion (OGD/R) injury to establish ischemic-like conditions in vitro, and cells were further treated with 25, 50, or 100 μM GPC. Cells were grouped into control, OGD/R, OGD/R+25 μM GPC, OGD/R+50 μM GPC, and OGD/R+100 μM GPC. GPC's function on rat cerebral injury, angiogenesis, oxidative stress, neuronal injury and immune dysfunction in vivo was estimated using hematoxylin-eosin staining, Western blot, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining, commercial kits and enzyme linked-immunosorbent assay. Meanwhile, GPC's mechanism in CI/R injury was examined via Western blot. GPC's function in vitro was estimated via Cell Counting Kit-8 assay, 5-ethynyl-2'-deoxyuridine (EdU) staining, flow cytometry.

RESULTS

GPC alleviated cerebral injury through decreasing cerebral infarction volume, cerebral indexes, brain water contents (p < 0.05). GPC reduced oxidative stress and boosted cerebral angiogenesis in CI/R rats (p < 0.05). Meanwhile, GPC weakened neuronal cell apoptosis, and decreased neuron-specific enolase and S100beta protein levels in CI/R rats. GPC reduced inflammatory cytokines contents in serum and brain tissues of CI/R rats (p < 0.05). Moreover, GPC increased the viability and proliferation in OGD/R-treated neuronal cells, but decreased cell apoptosis (p < 0.05). Mechanistically, GPC upregulated vascular endothelial growth factor (VEGF) and phosphorylated nuclear factor E2-related factor 2 (p-Nrf2) levels in CI/R rat brain tissues (p < 0.05).

CONCLUSIONS

GPC reduced cerebrovascular angiogenesis, neuronal injury and immune disorder in CI/R injury through elevating VEGF and p-Nrf2.

Gentiopicroside-Loaded Chitosan Nanoparticles Inhibit TNF-α-Induced Proliferation and Inflammatory Response in HaCaT Keratinocytes and Ameliorate Imiquimod-Induced Dermatitis Lesions in Mice

Purpose

In this study, we aimed to report the biological characteristics of the first successful synthesis of gentiopicroside-loaded chitosan nanoparticles and to evaluate the therapeutic effects and preliminary mechanisms of gentiopicrin-loaded chitosan on psoriasis-like cell and mouse models.

Methods

Gentiopicroside-loaded chitosan nanoparticles (CHI-GEN) were prepared, and their biological characteristics were evaluated. HaCaT keratinocytes were stimulated with TNF-α to establish a psoriatic keratinocyte model. MTT assay and flow cytometry were used to measure cell viability and apoptosis, respectively. mRNA levels of K17, VEGF A, and IL-6 and IL-23A were detected using qRT-PCR. These tests were used to preliminarily assess the effects of CHI-GEN on keratinocyte proliferation and inflammation. Imiquimod was used to construct a psoriasis-like mice model. The severity of psoriasis was scored based on the psoriasis area severity index (PASI), H&E staining was used to observe the histological changes and the level of inflammation and cell proliferation of skin lesions was evaluated by measuring the mRNA levels of K17, IL-23A, and IL-17A using qRT-PCR.

Results

The average particle size of CHI-GEN nanoparticles was approximately 100 nm, and the zeta potential was 2.69 ± 0.87 mV. The cumulative release was 67.2% in solutions of pH 5.5 at 24 h. GEN reduced TNF-α-induced excessive proliferation of HaCaT keratinocytes and downregulated mRNA levels of K17, VEGF A, and inflammatory cytokines IL-6 and IL-23A, which was more obvious in the CHI-GEN treatment group. Additionally, CHI-GEN significantly improved the severity of skin lesions in psoriasis-like mice and downregulated the mRNA expressions of IL-6, IL-23A, and IL-17A in mice skin lesions.

Conclusion

In conclusion, we successfully prepared gentiopicrin-chitosan nanoparticles. Our results show that these nanoparticles have anti-psoriasis activity, inhibits keratinocyte proliferation and improves symptoms in psoriasis model mice and can be used to develop an effective strategy for the treatment of psoriasis.

Gentiopicroside enhances the protective effect of trimetazidine against myocardial ischemia-reperfusion injury via the AMPK/NLRP3 inflammasome signaling

Myocardial ischemia-reperfusion injury (MI/R) leads to the inevitable clinical consequences of myocardial infarction and subsequent heart failure. Trimetazidine (TMZ), an anti-ischemic agent, exerts protective potential in MI/R but had limited efficacy for some patients. Here we sought to investigate the single and combined application of gentiopicroside (GPS) and TMZ in MI/R. Notably, GPS had little cytotoxicity to cardiomyocytes. GPS attenuated hypoxia/reoxygenation (H/R)-induced cell death, reactive oxygen species production, lactate dehydrogenase and malondialdehyde releases, and antioxidant stress enzyme superoxide dismutase activity, indicating the protective efficacy of GPS against H/R-induced oxidative injury. Importantly, GPS enhanced the protective efficacy of TMZ against H/R-mediated cardiomyocyte injury. Additionally, GPS mitigated the transcription and releases of pro-inflammatory cytokine interleukin-6 and tumor necrosis factor-α in H/R-treated cardiomyocytes, which were enhanced after co-treatment with TMZ. Mechanistically, GPS activated the AMP-activated protein kinase (AMPK) signaling to inhibit H/R-induced NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome, which was further enhanced after costimulation with TMZ. Importantly, blocking the AMPK signaling reversed the protective roles of GPS and its combination with TMZ in H/R-induced oxidative insult and inflammation. In vivo, both GPS and TMZ alleviated the abnormal cardiac structure, cardiomyocyte apoptosis, and cardiac dysfunction in MI/R rats, which were further enhanced after administration with GPS and TMZ together. Furthermore, GPS intensified TMZ-mediated inhibition of oxidative injury, inflammation, and the AMPK/NLRP3 signaling in MI/R rats. Collectively, GPS enhances the protective efficacy of TMZ against MI/R injury through AMPK activation-mediated inhibition of NLRP3 inflammasome signaling, implying a promising therapeutic agent for the treatment of MI/R.

Safety of a feed additive consisting of a tincture derived from the roots of Gentiana lutea L. (gentian tincture) for all animal species (FEFANA asbl)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety of a tincture derived from Gentiana lutea L. (gentian tincture). It is intended to be used as a sensory additive for all animal species. The product is a water/ethanol solution, with a dry matter content of approximately 4.3% and it contains on average 0.0836% polyphenols (of which 0.0463% are flavonoids and 0.0027% xanthones) and 0.0022% gentiopicroside. The additive is intended for use in complete feed or drinking water up to a maximum level of 50 mg tincture/kg for all animal species, except horses, for which the proposed use is 200 mg/kg in complete feed. In a previous assessment, due to the genotoxic potential identified in vitro for xanthones (gentisin and isogentisin) and gentiopicroside the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) could not conclude on the safety of the additive for long-living animals and on risks of genotoxicity and carcinogenicity for dermal exposure of unprotected users. The additive did not raise safety concern for short-living animals, consumers and the environment. The applicant has provided information in the form of literature to address the previously identified genotoxic activity of xanthones and gentiopicroside and the risk for the user. Considering that the literature identified provided no new evidence, the FEEDAP Panel reiterated that it is not in a position to conclude on the safety of the additive for long-living and reproductive animals. No conclusions could be drawn on the potential of the additive to be a dermal/eye irritant or a skin sensitiser. When handling the tincture, exposure of unprotected users to xanthones (gentisin and isogentisin) and gentiopicroside cannot be excluded. Therefore, to reduce the risk, the exposure of the users should be minimised.

Preparation, Characterization, and In Vivo Evaluation of Gentiopicroside-Phospholipid Complex (GTP-PC) and Its Self-Nanoemulsion Drug Delivery System (GTP-PC-SNEDDS)

The objective of the present study was to develop a gentiopicroside-phospholipid complex (GTP-PC) and its self-nanoemulsion drug delivery system (GTP-PC-SNEDDS) to increase the oral bioavailability of gentiopicroside (GTP). The factors affecting the formation of GTP-PC were studied with the complexation efficiency and dissociation rate. The properties of the complex were investigated by means of differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), dissolution, etc. Then, GTP-PC was loaded into SNEDDS by investigating the effects of weight ratios of GTP-PC to blank SNEDDS, preparation technology, dilution media, and dilution multi, based on the screening results of oils, surfactants, and cosurfactants. In rats, GTP, GTP-PC, and GTP-PC-SNEDDS were orally administered at different times, and GTP concentrations were determined using RP-HPLC. The optimal GTP-PC was prepared with tetrahydrofuran as the reaction solvent, GTP:phospholipid = 1:2, and stirring for 4 h. The optimal prescription for GTP-PC-SNEDDS was as follows: Maisin 35-1:Miglycol = 30%, Labrasol:Cremophor EL = 1:4 = 40%, Transcutol P = 30%; Maisin 35-1:Miglycol = 12, and the ratio of GTP-PC to blank was 1:10-then the mixture was stirred at 37 °C for 1 d and then placed for 2 d to form stable GTP-PC-SNEDDS. After oral administration of GTP, GTP-PC and GTP-PC-SNEDDS, and mean plasma GTP concentration-time curves were all in accordance with the single-compartment model. The C_max, AUC_0-∞, and Fr of the three formulations were significantly higher than that of GTP, demonstrating that GTP was metabolized rapidly, and its higher bioavailability could be achieved by the formation of GTP-PC and GTP-PC-SNEDDS. Among the three formations, the bioavailability of GTP-PC-SNEDDS was highest, with approximately 2.6-fold and 1.3-fold of Fr value, compared with GTP-PC (suspension) and GTP-PC (oil solution), respectively. Compared with GTP, GTP-PC and GTP-PC-SNEDDS enhanced the bioavailability of GTP significantly. In the future, this study could serve as a reference for clinical trials using GTP-PC and GTP-PC-SNEDDS.

Development of Lipid-Based Gastroretentive Delivery System for Gentian Extract by Double Emulsion-Melt Dispersion Technique

Gentian (Gentiana lutea L., Gentianaceae) root extract (GRE) is used for the treatment of gastrointestinal disorders. However, its bioactive potential is limited in conventional forms due to the low bioavailability and short elimination half-life of the dominant bioactive compound, gentiopicroside. The aim of study was to encapsulate GRE in the lipid-based gastroretentive delivery system that could provide high yield and encapsulation efficiency, as well as the biphasic release of gentiopicroside from the tablets obtained by direct compression. Solid lipid microparticles (SLM) loaded with GRE were prepared by freeze-drying double (W/O/W) emulsions, which were obtained by a multiple emulsion-melt dispersion technique, with GRE as the inner water phase, Gelucire^® 39/01 or 43/01, as lipid components, with or without the addition of porous silica (Sylysia^® 350) in the outer water phase. Formulated SLM powders were examined by SEM and mercury intrusion porosimetry, as well as by determination of yield, encapsulation efficiency, and flow properties. Furthermore, in vitro dissolution of gentiopicroside, the size of the dispersed systems, mechanical properties, and mucoadhesion of tablets obtained by direct compression were investigated. The results have revealed that SLM with the macroporous structure were formulated, and, consequently, the powders floated immediately in the acidic medium. Formulation with porous silica (Sylysia^® 350) and Gelucire^® 43/01 as a solid lipid was characterized with the high yield end encapsulation efficiency. Furthermore, the mucoadhesive properties of tablets obtained by direct compression of that formulation, as well as the biphasic release of gentiopicroside, presence of nanoassociates in dissolution medium, and optimal mechanical properties indicated that a promising lipid-based gastroretentive system for GRE was developed.

Safety and efficacy of a feed additive consisting of a tincture derived from roots of Gentiana lutea L. (gentian tincture) for use in all animal species (FEFANA asbl)

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of a tincture from the roots of Gentiana lutea L. (gentian tincture) when used as a sensory feed additive for all animal species. The product is a ■■■■■ solution, with a dry matter content of approximately 4.3%. The product contains on average 0.0836% polyphenols (of which 0.0463% are flavonoids and 0.0027% xanthones) and 0.0022% gentiopicroside. The FEEDAP Panel concludes that gentian tincture is safe at the maximum proposed use level of 50 mg/kg complete feed for short-living animals (animals for fattening). The FEEDAP Panel considers that the use in water for drinking is safe provided that the total daily intake of the additive does not exceed the daily amount that is considered safe when consumed via feed. Considering the genotoxic potential of gentiopicroside and xanthones (gentisin and isogentisin), no conclusions can be drawn for long-living animals (companion animals, horses and animals for reproduction). No safety concern would arise for the consumer from the use of gentian tincture up to the highest safe level in animal nutrition. In the absence of data, no conclusions can be drawn on the potential of the tincture to be a dermal/eye irritant or a skin sensitiser. The data available do not allow to conclude on risks of genotoxicity and carcinogenicity for dermal exposure. Use of the tincture derived from G. lutea as a flavour in animal feed is not expected to pose a risk for the environment. Since G. lutea and gentian root extract are recognised to flavour food and their function in feed would be essentially the same as that in food, no further demonstration of efficacy is considered necessary for the tincture under application.

Gentiopicroside prevents alcoholic liver damage by improving mitochondrial dysfunction in the rat model

Gentianae Radix et Rhizoma is a medical plant that is widely cultivated in China, North Korea, Japan, and Russia, and gentiopicroside is one of its major active compounds. In this study, the hepatoprotective activity of gentiopicroside on rats with alcoholic liver damage (ALD) was evaluated using the transaminase and blood lipid levels and antioxidant capacity. The potential mechanism of hepatoprotective effect of gentiopicroside was evaluated by mitochondrial function detection, gas chromatography-mass spectrometry (GC-MS) metabolomic analysis, and anti-apoptosis analysis. Results showed that the gentiopicroside exhibited good hepatoprotective activity on rats with ALD by decreasing the transaminase levels, regulating the blood lipid levels, and increasing the antioxidant capacity. The potential mechanisms were related to regulating mitochondrial dysfunction by recovering mitochondrial membrane potential level, adenosine triphosphate concentration, activities of key enzymes in tricarboxylic acid cycle, and activities of complex I-V, regulating micromolecular metabolism and anti-apoptosis. These findings supported the further exploration of Gentianae Radix et Rhizoma as effective phytotherapy to prevent and treat ALD.

Microbial Biotransformation of Iridoid Glycosides from Gentiana Rigescens by Penicillium Brasilianum

This study aimed to investigate the metabolic effects of endophytic fungi in Gentiana rigescens. From the 100 selected morphospecies, strain 7-2 (Penicillium brasilianum) showed a remarkable biocatalytic activity for gentiopicroside and swertiamarin, yielding seven products, including one new compound, 5-ethylidene-8-hydroxy-4,5,6,8-tetrahydropyrano[3,4-c]pyran-1-one (M04), alongside six known compounds. Gentianine (M01) was the only metabolite of swertiamarin in this study, while the remaining ones were all gentiopicroside metabolites. Among these, five compounds: gentianine (M01), (5S,6S)-5-(hydroxymethyl)-6-methyl-5,6-dihydro-1H,3H-pyrano[3,4-c]pyran-1-one (M02), (5R,6S)-5-(hydroxymethyl)-6-methyl-5,6-dihydro-1H,3H-pyrano[3,4-c]pyran-1-one (M03), 2-(3-formyl-2-oxo-3,6-dihydro-2H-pyran-4-yl)but-3-enoic acid (M06), and 2-oxo-4-(1-oxobut-3-en-2-yl)-3,6-dihydro-2H-pyran-3-carboxylic acid (M07) were similar to gentiopicroside metabolites in humans. Screening the metabolic potential of endophytic fungi in Gentiana rigescens provides an outstanding source for assessing the bioactive metabolites of iridoid glycosides. The above findings suggested that the endophytic fungi of G. rigescens possess multi-enzyme systems that mimic metabolic reactions in mammalian organisms.

[Determination of content of iridoids and flavonoids in Tibetan medicine "Lanhua Longdan" by quantitative analysis of multi-components by single marker (QAMS)]

In this study, the content of iridoids and flavonoids in Tibetan medicine &quot;Lanhua Longdan&quot; was determined simul-taneously by quantitative analysis of multi-components by single marker(QAMS), which was used to verify the feasibility and applicability of the method in the application of Lanhua Longdan quality evaluation. Using HPLC with two typical elements gentiopicroside and isoorientin as the internal reference, the relative correction factor(RCF) between the mand loganin acid, swertiamarin, sweroside, isoscoparin-2″-β-D-glucopyranoside and isoscoparin was determined and then used, to calculate the content of several other components to achieve QAMS. At the same time, the external standard method(ESM) was used to determine the contents of these 7 components in the medicinal materials, and the differences were compared to verify the accuracy and feasibility of QAMS. The results showed that the RCF repeatability is good. There were no significant differences in the determination results of the contents of 12 batches of 4 varieties of Tibetan medicine Lanhua Longdan obtained by QAMS and ESM. Therefore, the QAMS can be used for the quality evaluation of Lanhua Longdan, and provides a reference for the quality evaluation of multi-index components of Lanhua Longdan. The results showed that the content of iridoid and flavonoid in the dried product should not be less than 0.6% and 0.8% respectively.

Anti-Rheumatic Properties of Gentiopicroside Are Associated With Suppression of ROS-NF-κB-NLRP3 Axis in Fibroblast-Like Synoviocytes and NF-κB Pathway in Adjuvant-Induced Arthritis

Rheumatoid arthritis (RA) is among the most prevalent forms of autoimmunity. Gentiopicroside (Gent) is an iridoid glucoside derived from the Gentiana Macrophylla Pall which is used in traditional Chinese medicine to treat RA. The present study was designed to explore the ability of Gent to combat RA and to explore the molecular basis for such anti-RA activity both in vitro using tumor necrosis factor alpha (TNF-α)-stimulated human RA fibroblast-like synoviocytes (RA-FLS) and in vivo using a rat adjuvant-induced arthritis (AIA) model. We found that Gent was able to significantly reduce the swelling of joints and arthritic index scores, with corresponding reductions in synovial inflammatory cell infiltration, synovial hyperplasia, and bone erosion in treated AIA rats. Importantly, Gent 200 mg/kg reduced thymus index in AIA rats, but had no effect on spleen index and body weight, it revealed that Gent was relatively safe at the dose we chose. We further found that Gent was able to suppress the TNF-α-induced proliferation and migration of RA-FLS cells. This suppression was attributed to the ability of Gent to block NOD-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein containing a CARD (ASC), and caspase-1, thereby disrupting the activation of the NLRP3 inflammasome. Consistent with such suppression, Gent led to a significant decrease in IL-1β secretion by treated cells. Furthermore, this reduction in NLRP3 inflammasome activation was also associated with decreases in the activation of nuclear factor (NF-κB), the production of reactive oxygen species (ROS), and the expression of inflammatory IL-6. Together these findings indicate that Gent can suppress the ROS-NF-κB-NLRP3 axis to alleviate RA symptoms.

Bioactivities of Centaurium erythraea (Gentianaceae) Decoctions: Antioxidant Activity, Enzyme Inhibition and Docking Studies

Centaurium erythraea is recommended for the treatment of gastrointestinal disorders and to reduce hypercholesterolemia in ethno-medicinal practice. To perform a top-down study that could give some insight into the molecular basis of these bioactivities, decoctions from C. erythraea leaves were prepared and the compounds were identified by liquid chromatography-high resolution tandem mass spectrometry (LC–MS/MS). Secoiridoids glycosides, like gentiopicroside and sweroside, and several xanthones, such as di-hydroxy-dimethoxyxanthone, were identified. Following some of the bioactivities previously ascribed to C. erythraea, we have studied its antioxidant capacity and the ability to inhibit acetylcholinesterase (AChE) and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR). Significant antioxidant activities were observed, following three assays: free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) reduction; lipoperoxidation; and NO radical scavenging capacity. The AChE and HMGR inhibitory activities for the decoction were also measured (56% at 500 μg/mL and 48% at 10 μg/mL, respectively). Molecular docking studies indicated that xanthones are better AChE inhibitors than gentiopicroside, while this compound exhibits a better shape complementarity with the HMGR active site than xanthones. To the extent of our knowledge, this is the first report on AChE and HMGR activities by C. erythraea decoctions, in a top-down analysis, complemented with in silico molecular docking, which aims to understand, at the molecular level, some of the biological effects ascribed to infusions from this plant.

induce phosphorylation of Akt and suppress Pck1 expression in hepatoma cells

The use of phytochemicals and herbal medicines has accompanied human history. Advances in modern biomedical sciences have allowed us to investigate the functional mechanisms of herbal medicines and phytochemicals. Veratrilla baillonii Franch. has long been used as a medicinal herb in southwestern China. Here, we analyzed the effects of an ethanol extract from V. baillonii (VBFE) on the expression levels of the cytosolic form of the phosphoenolpyruvate carboxykinase gene (Pck1) mRNA and components of the insulin signalling cascade in HL1C hepatoma cells. Compared with the insulin control, VBFE treatment inhibited the expression of Pck1 mRNA in a dose-dependent manner. This was associated with the phosphorylation of Akt and Erk1/2 in a time-dependent manner. Further analysis of the purified components of VBFE indicated that gentiopicroside and sweroside from VBFE, alone and in combination, suppressed Pck1 expression and induced Akt and Erk1/2 phosphorylation. In conclusion, gentiopicroside and sweroside suppress Pck1 expression and induce phosphorylation of components in the insulin signalling cascade. This is the first study to demonstrate that gentiopicroside and sweroside show insulin-mimicking effects on the regulation of Pck1 expression. Further studies are warranted to explore the potential of gentiopicroside and sweroside in the control of blood glucose in animals.

Antinociceptive effects of gentiopicroside on neuropathic pain induced by chronic constriction injury in mice: a behavioral and electrophysiological study

Gentiopicroside (Gent) is promising as an important protective secoiridoid compound against pain. The present study was designed to investigate whether administration of Gent would alleviate the expression of nociceptive behaviors and whether it would cause the relevant electrophysiological changes in a chronic constriction injury (CCI) model of neuropathic pain in mice. Gent was administered from the seventh day after surgery for 8 consecutive days. Behavioral parameters and sciatic functional index were assessed immediately before surgery and on days 7, 8, 10, 12, and 14 post-CCI, and electrophysiological activities of sciatic nerve were recorded immediately after the behavioral test on the last day. The present study has shown that administration of Gent (at a dose of 50 and 100 mg/kg) increased behavioral parameters from day 8 compared with the CCI-NS group. Electrophysiological data indicated that CCI caused a significant reduction in nerve conduction velocities in the sciatic nerves and the amplitudes of compound action potential, while Gent at a dose of 50 or 100 mg/kg caused a significant recovery of electrophysiological changes induced by CCI. Our data indicated that Gent has antinociceptive effects on neuropathic pain induced by CCI.

De Novo Assembly and Characterization of the Transcriptome of the Chinese Medicinal Herb, Gentiana rigescens

Gentiana rigescens is an important medicinal herb in China. The main validated medicinal component gentiopicroside is synthesized in shoots, but is mainly found in the plant's roots. The gentiopicroside biosynthetic pathway and its regulatory control remain to be elucidated. Genome resources of gentian are limited. Next-generation sequencing (NGS) technologies can aid in supplying global gene expression profiles. In this study we present sequence and transcript abundance data for the root and leaf transcriptome of G. rigescens, obtained using the Illumina Hiseq2000. Over fifty million clean reads were obtained from leaf and root libraries. This yields 76,717 unigenes with an average length of 753 bp. Among these, 33,855 unigenes were identified as putative homologs of annotated sequences in public protein and nucleotide databases. Digital abundance analysis identified 3306 unigenes differentially enriched between leaf and root. Unigenes found in both tissues were categorized according to their putative functional categories. Of the differentially expressed genes, over 130 were annotated as related to terpenoid biosynthesis. This work is the first study of global transcriptome analyses in gentian. These sequences and putative functional data comprise a resource for future investigation of terpenoid biosynthesis in Gentianaceae species and annotation of the gentiopicroside biosynthetic pathway and its regulatory mechanisms.