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.

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.

CONTEXTE: Le contour des yeux est une zone sensible. Les cernes affectent les sujets de tout âge et de tout type de peau. Différentes solutions peuvent être proposées, dont les solutions topiques. Cette étude visait a explorer l'effet d'un extrait de Gentiana lutea (GIE) riche en gentiopicroside (65% de matière sèche) sur des paramètres d'oxydation et d'angiogenèse au moyen d'études in vitro et ex-vivo. Une expérimentation clinique a également été réalisée. MÉTHODES: L'effet du GIE a différentes concentrations sur des gènes antioxydants a été évalué in vitro par RT-qPCR après traitement de fibroblastes (NHDF). L'effet de 2.93 µg mL−1 GIE sur la libération de VEGF-A et VEGF-C a également été étudié. Il en est de même pour l'effet de 87.9 µg g mL−1 GIE sur la formation de pseudotubes qui a été évalué dans un système de co-culture de cellules endothéliales (HMVEC-d)- NHDF stimulées ou non avec du VEGF comme facteur pro-angiogénique. Les expressions de la carboxymethyl-lysine et de la glyoxalase-1 ont été quantifiées sur des explants cutanés traites par voie topique avec 147 µg g mL−1 GIE dans des conditions basales et irradiées par UVA. Une étude clinique a été menée sur vingt-deux sujets en utilisant un traitement topique deux fois par jour pendant 14 jours sur le contour des yeux (crème contenant 147 µg g mL−1 GIE contre placebo). L'acquisition d'images 3D et la mesure de la couleur de la peau ont été réalisées a J0 et J14. RÉSULTATS: Le traitement par GIE a augmenté l'expression génétique de NFE2L2 et diminue l'expression de CXCL8. GIE a cible les voies des AGEs et a réduit la formation de pseudotubes. 147 µg g mL−1 GIE gel crème a significativement réduit la rugosité moyenne et le relief de la peau de la paupière supérieure ainsi que la rougeur des cernes après 14 jours d'application. CONCLUSION: En agissant sur la voie des AGEs, du VEGF-A et du VEFG-C, GIE semble permettre un rajeunissement de la peau se traduisant, entre autres, par une diminution des rougeurs. Il serait maintenant intéressant d'évaluer l'efficacité du GIE sur le microbiote de la peau du contour des yeux, la propriété antibactérienne du gentiopicroside étant bien établie.

Gentiopicroside promotes the osteogenesis of bone mesenchymal stem cells by modulation of ß-catenin-BMP2 signalling pathway.

Osteoporosis is characterized by increased bone fragility, and the drugs used at present to treat osteoporosis can cause adverse reactions. Gentiopicroside (GEN), a class of natural compounds with numerous biological activities such as anti-resorptive properties and protective effects against bone loss. Therefore, the aim of this work was to explore the effect of GEN on bone mesenchymal stem cells (BMSCs) osteogenesis for a potential osteoporosis therapy. In vitro, BMSCs were exposed to GEN at different doses for 2 weeks, whereas in vivo, ovariectomized osteoporosis was established in mice and the therapeutic effect of GEN was evaluated for 3 months. Our results in vitro showed that GEN promoted the activity of alkaline phosphatase, increased the calcified nodules in BMSCs and up-regulated the osteogenic factors (Runx2, OSX, OCN, OPN and BMP2). In vivo, GEN promoted the expression of Runx2, OCN and BMP2, increased the level of osteogenic parameters, and accelerated the osteogenesis of BMSCs by activating the BMP pathway and Wnt/ß-catenin pathway, effect that was inhibited using the BMP inhibitor Noggin and Wnt/ß-catenin inhibitor DKK1. Silencing the ß-catenin gene and BMP2 gene blocked the osteogenic differentiation induced by GEN in BMSCs. This block was also observed when only ß-catenin was silenced, although the knockout of BMP2 did not affect ß-catenin expression induced by GEN. Therefore, GEN promotes BMSC osteogenesis by regulating ß-catenin-BMP signalling, providing a novel strategy in the treatment of osteoporosis.

Gentiopicroside ameliorates ovalbumin-induced airway inflammation in a mouse model of allergic asthma via regulating SIRT1/NF-κB signaling pathway.

Allergic asthma is a common airway inflammatory disorder with increasing morbidity and mortality worldwide. Gentiopicroside (GPS) is a secoiridoid glycoside compound that exhibits anti-inflammatory property. However, the effect of GPS on allergic asthma has not been reported yet. In this study, we investigated the role of GPS in a mouse model of ovalbumin (OVA)-induced allergic asthma and explored its potential mechanism. Mice were sensitized with OVA and gavaged with 20, 40, or 80 mg/kg GPS. Administration of GPS decreased lung wet-to-dry weight ratio. Histological analysis of H&E and PAS staining showed that GPS treatment alleviated inflammatory cell infiltration and goblet cell hyperplasia in lung tissue of OVA-sensitized mice. Moreover, GPS inhibited the recruitment of inflammatory cells including total cells, macrophages, eosinophils, lymphocytes and neutrophils and the secretion of T helper type 2 (Th2) cytokines (interleukin (IL)-4, IL-5 and IL-13) in bronchoalveolar lavage fluid (BALF) of OVA-sensitized mice in a dose dependent manner. The levels of OVA-specific immunoglobulin E (IgE) and pro-inflammatory tumor necrosis factor (TNF)-α were also attenuated by GPS treatment. Interestingly, GPS upregulated the expression of silent information regulator 1 (SIRT1) while downregulated the expression of acetyl-nuclear factor kappa B (NF-κB) p65 in lung tissue of OVA-sensitized mice. Furthermore, treatment with an SIRT1 inhibitor (EX-527) partially abolished the inhibitory effect of GPS on OVA-induced airway inflammation, suggesting that the anti-inflammation of GPS might be achieved through regulating SIRT1/NF-κB p65 signaling pathway. These findings indicate that GPS might be a novel drug candidate in the treatment of allergic asthma.

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.

Gentiopicroside activates the bile acid receptor Gpbar1 (TGR5) to repress NF-kappaB pathway and ameliorate diabetic nephropathy.

Our previous studies indicated that the G-protein-coupled bile acid receptor, Gpbar1 (TGR5), inhibits inflammation by inhibiting the NF-κB signalling pathway, eventually attenuating diabetic nephropathy (DN). Gentiopicroside (GPS), the main active secoiridoid glycoside of Gentiana manshurica Kitagawa, has been demonstrated to inhibit inflammation in various diseases via inhibiting the inflammatory signalling pathways. However, whether GPS inhibits the NF-κB signalling pathway by activating TGR5 and regulates the pathological progression of diabetic renal fibrosis requires further investigation. In this study, we found that GPS significantly reversed the downregulation of TGR5 and inhibited the overproduction of fibronectin (FN), transforming growth factor ß1 (TGF-ß1), intercellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) in glomerular mesangial cells (GMCs) exposed to high glucose (HG). Additionally, GPS prevented the phosphorylation and degradation of IκBα, and subsequently inhibited the activation of the NF-κB signalling pathway. Further investigation found that GPS enhanced the stabilization of IκBα by promoting the interaction of ß-arrestin2 with IκBα via TGR5 activation, which contributed to the inhibition of NF-κB signalling pathway. Importantly, the depletion of TGR5 blocked the inhibition of the NF-κB signalling pathway and reversed the downregulation of FN, ICAM-1, VCAM-1 and TGF-ß1 by GPS in HG-induced GMCs. Moreover, GPS increased the TGR5 protein levels and promoted the interaction between IκBα and ß-arrestin2, thereby inhibiting the reduction of IκBα and blocked NF-κB p65 nuclear translocation in the kidneys of STZ-induced diabetic mice. Collectively, these data suggested that GPS regulates the TGR5-ß-arrestin2-NF-κB signalling pathway to prevent inflammation in the kidneys of diabetic mice, and ultimately ameliorates the pathological progression of diabetic renal fibrosis.

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 "Lanhua Longdan" 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″-ß-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.

Gentiopicroside isolated from Gentiana scabra Bge. inhibits adipogenesis in 3T3-L1 cells and reduces body weight in diet-induced obese mice.

Gentiopicroside is a major active component of the Gentiana scabra Bge., which is commonly used as herbal medicine for the treatment of inflammation in Asia. Gentiopicroside significantly down-regulated expression of key adipogenic transcription factors (PPARγ, C/EBPα, SREBP-1c) and dose-dependently inhibited the lipid uptake-related gene (LPL), fatty acid transport-related gene (FABP4) and triglyceride (TG) synthesis-related gene (DGAT2), as well as fatty acid synthesis-related genes (FAS, SCD1), which resulted in reduced intracellular lipid droplet accumulation and TG content in 3T3-L1 cells. Gentiopicroside also down-regulated expression of inflammatory cytokine genes (NFκB1, TNFα, IL6) compared with vehicle. Oral administration of gentiopicroside (50 mg/kg) in mice fed with high-fat diet for 12 weeks resulted in reduced body weight and visceral fat mass compared with the control group. Overall, the results of this study showed that gentiopicroside had positive anti-obesity effects by regulating the expression of adipogenesis/lipogenesis-related genes and inflammatory genes in 3T3-L1, and that it effectively reduced body weight and visceral fat mass in vivo.

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.

Exploration of Hepatoprotective Effect of Gentiopicroside on Alpha-Naphthylisothiocyanate-Induced Cholestatic Liver Injury in Rats by Comprehensive Proteomic and Metabolomic Signatures.

BACKGROUND/AIMS: Cholestasis is the major cause of the accumulation of bile acids and results in liver damage, fibrosis, and failure. A growing number of studies have shown that gentiopicroside is a promising prospect that may protect the liver. However, its therapeutic mechanism has not yet been clarified. This study aimed to explore the effect and mechanism of gentiopicroside in cholestasis induced by alpha-naphthylisothiocyanate. METHODS: We performed isobaric tags for relative and absolute quantification-based quantitative proteomics and metabolomics using liquid chromatography quadruple time-of-fight mass spectrometry and identified the expression of 73 metabolites and 84 proteins associated with cholestasis-related dysfunctions in the metabolism of bile acids, fatty acids, and glycerophospholipids. RESULTS: Integrated analyses of proteomic and metabonomic studies showed altered pathways in cholestasis-induced liver injury involving increased activity of farnesoid X receptor/retinoid X receptor, bile acid biosynthesis, and peroxisome proliferator-activated receptor-α/retinoid X receptor-α. Gentiopicroside could reverse these metabolite, protein, and blood biochemical indices, as well as alleviate liver damage. The progressive changes in the proteins and genes may be correlated with cholestasis and were confirmed by western blot and quantitative realtime polymerase chain reaction. CONCLUSION: Gentiopicroside could be used to protect the liver in the presence of cholestasis.

Gentiopicroside Ameliorates Diabetic Peripheral Neuropathy by Modulating PPAR- Γ/AMPK/ACC Signaling Pathway.

BACKGROUND/AIMS: Gentiopicroside is promising as an important secoiridoid compound against pain. The present study aimed to investigate the analgesic effect and the probable mechanism of Gentiopicroside on Diabetic Peripheral Neuropathy (DPN), and to figure out the association among Gentiopicroside, dyslipidemia and PPAR- γ/AMPK/ACC signaling pathway. METHODS: DPN rat models were established by streptozotocin and RSC96 cells were cultured. Hot, cold and mechanical tactile allodynia were conducted. Blood lipids, nerve blood flow, Motor Nerve Conduction Velocity (MNCV) and Sensory Nerve Conduction Velocity (SNCV) were detected. Gene and protein expression of PPAR- γ/AMPK/ACC pathway was analyzed by reverse transcription-quan titative polymerase chain reaction (RT-qPCR) and Westernblot. Besides, PPAR-γ antagonist GW9662 and agonist rosiglitazone, AMPK antagonist compound C and activator AICAR as well as ACC inhibitor TOFA were used to further confirm the relationship between PPAR-γ and AMPK. RESULTS: The results demonstrated that Gentiopicroside markedly ameliorated hyperalgesia with prolonged paw withdrawal latency to heat and cold stimuli and fewer responses to mechanical allodynia compared with DPN model group. Gentiopicroside regulated dyslipidemia, enhanced nerve blood flow and improved MNCV as well as SNCV. Gentiopicroside suppressed ACC expression through the activation of AMPK and PPAR-γ mediated the activation of AMPK and subsequent inhibition of ACC expression. CONCLUSION: In conclusion, the present study demon strated that Gentiopicroside exerted nerve-protective effect and attenuated experimental DPN by restoring dyslipidmia and improved nerve blood flow through regulating PPAR-γ/AMPK/ACC signal pathway. These results provided a promising potential treatment of DPN.

Gentiopicroside ameliorates bleomycin-induced pulmonary fibrosis in mice via inhibiting inflammatory and fibrotic process.

Pulmonary fibrosis (PF) is a chronic and ultimately fatal interstitial lung disease of various causes. The advent of nintedanib and pirfenidone provides treatment options for PF patients for the first time. However, the adverse effects of the two drugs such as gastrointestinal disorders and hepatic dysfunction often lead to treatment discontinuation. Gentiopicroside (GPS) is a natural secoiridoid glycoside from gentian species of medicinal plants, and has a variety of pharmacological activities, including hepatoprotective and cholagogic, anti-inflammatory, antinociceptive, and smooth muscle relaxing activities. The present study aimed to investigate the therapeutical effects of GPS on bleomycin (BLM)-induced PF in mice. Severe lung inflammation and fibrosis were observed in BLM-treated mice. GPS significantly ameliorated inflammatory and fibrotic responses in lungs of PF mice which were confirmed by histopathological examinations including light microscopy and transmission electron microscopy. Additionally, GPS significantly decreased the levels of inflammatory cytokines including TNF-α and IL-1ß in bronchoalveolar lavage fluid and reduced the content of hydroxyproline in lungs of PF mice. Furthermore, GPS significantly downregulated the expression of TGF-ß1 and CTGF in lungs of PF mice. In vitro, GPS inhibited epithelial-mesenchymal transition of A549 cells stimulated by TGF-ß1, in a dose-dependent manner. Our findings suggest that GPS has the potential as an ideal drug candidate for PF, as it has both anti-inflammatory and anti-fibrotic effects. Alveolar epithelial cells and TGF-ß1 may be the main target cells and molecule of GPS on BLM-induced PF, respectively.

Gentiopicroside abrogates lipopolysaccharide-induced depressive-like behavior in mice through tryptophan-degrading pathway.

Targeting neuroinflammatory disturbances has been acknowledged as a potential strategy for treatment of depressive disorder in humans. Over-activation of tryptophan-degrading pathway by pro-inflammatory cytokines resulted in N-methyl-d-aspartate (NMDA)-mediated excitotoxicity, which is implicated in pathophysiology of depression. Gentiopicroside (Gent) has powerful anti-inflammatory property and exhibits promising antidepressant effect in an animal model of pain/depression dyad by down-regulating GluN2B-containing NMDA receptors. Therefore, the present study aimed to investigate the ability of Gent to abolish depressive-like behavior induced by lipopolysaccharide (LPS) in mice. Acute administration of LPS (0.5 mg/kg, i.p.) increased immobility time in both forced swimming test (FST) and tail suspension test (TST) without affecting spontaneous locomotor activity, indicative of depressive-like behavior. Gent (50 mg/kg, i.p.) administered once a day for three consecutive days prevented the development of depressive-like behavior induced by LPS. The antidepressant-like effect was paralleled with restoration of LPS-induced alterations in brain inflammatory mediators (i.e. IL-1ß and TNF-α). In addition, Gent prevented over-activation of indoleamine 2,3-double oxygen enzyme (IDO) and recovered GluN2B subunit expression in the PFC challenged by LPS. In conclusion, our results suggested that Gent pretreatment provided protection against LPS-induced depressive-like behavior and the effect appeared to be demonstrated, at least partially, by blocking various steps of tryptophan-degrading pathway.

Protective effect of gentiopicroside from Gentiana macrophylla Pall. in ethanol-induced gastric mucosal injury in mice.

Gentiopicroside isolated from gentiana macrophylla Pall. belongs to iridoid glycosides. This study aimed to evaluate the protective effect of gentiopicroside against ethanol-induced gastric mucosal injury in mice. Mice were proactively administrated with gentiopicroside by intragastric administration once a day for 3 consecutive days. On the 3rd day, gastric ulcer in mice was induced with 70% ethanol after the last intragastric administration. The stomach tissues were submitted for evaluation of the severity of gastric mucosal alterations. Gentiopicroside administrated orally ameliorated the severity of gastric mucosal alterations. Oral administration of gentiopicroside significantly increased heat shock protein-70 and glutathione levels and superoxide dismutase activity, normalized epidermal growth factor and vascular endothelial growth factor levels, and decreased the levels of tumour necrosis factor-α, interleukin-6 and malondialdehyde, and myeloperoxidase activity in gastric tissue. These findings demonstrated that gentiopicroside has protective effect against ethanol-induced gastric mucosal injury in mice through the improvements of antioxidative and anti-inflammatory effects, as well as up-regulation of heat shock protein-70 level and normalization of epidermal growth factor and vascular endothelial growth factor levels. The results presented in this study provide some evidence for the development of a novel antigastric ulcer agent.

Gentiopicroside and sweroside from Veratrilla baillonii Franch. 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.

[Effect of D-cellobiose on oral bioavailability of gentiopicroside].

In this study, the effect of D-cellobiose on oral bioavailability of gentiopicroside (GPS) was investigate. The influence of D-cellobiose on GPS was achieved by calculating the residual GPS after being degraded with ß-glucosidase or intestinal flora, and the data demonstrated D-cellobiose could inhibit the degradation of GPS in intestines; in bioavailability experiment, D-cellobiose could significantly improve the oral bioavailability (P<0.05) of GPS at the mass ratio of 1∶5, 1∶10 (GPS-D-cellobiose). D-cellobiose applied in this study may improve the oral bioavailability of GPS through delaying the degradation in intestines.

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.

New analytical method for the study of the metabolism of gentiopicroside in rats after oral administration by LC-TOF-MS following picolinoyl derivatization.

The metabolism of gentiopicroside (GPS) in vivo was studied for the first time by LC-MS following picolinoyl derivatization. Incubation of erythrocentaurin, one of the main in vitro metabolites of GPS by intestinal bacteria, with liver microsome indicated that GPS might be metabolized to a final metabolite 3,4-dihydro-5-(hydroxymethyl)isochroman-1-one (HMIO) in vivo. After hydrolysis with sulfatase, HMIO was successfully detected in rat plasma after oral administration of GPS by LC-MS following picolinoyl derivatization. 4-Methoxyphenyl methanol was used as an internal standard to quantify HMIO in rat plasma. A metabolic pathway of GPS in rats is proposed. The monoterpene compound GPS was found to be metabolized to dihydroisocoumarin, which may be responsible for the pharmacological effect of GPS.