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

Regulatory mechanisms of Gentiopicroside on human diseases: a brief review

Gentiopicroside (GPS), a single compound isolated from Gentiana lutea L. and the crucial representative of secoiridoid constituent, has been permitted for centuries in traditional Chinese medicine. GPS and its metabolites have been increasingly used in the search for clinical management with therapeutic properties and fewer side effects. The objective of this review was to provide a comprehensive overview of the involvement of molecular pathways in the therapeutic effects of GPS on human diseases and chronic conditions. This study presents a meticulously conducted comprehensive search of the PubMed and Google Scholar databases (from 1983 to 2023), aimed at identifying articles relating to regulatory mechanisms of GPS on human diseases and the pharmacokinetics of GPS. The inclusion criteria were meticulously and precisely defined to encompass original research papers that explicitly focused on elucidating the regulatory mechanisms of GPS in various human diseases through in vitro and animal studies. Notably, these studies were mandated to integrate specific genetic markers or pathways as essential components of their research inquiries. The evaluated pharmacokinetic parameters included maximum plasma concentration (Cmax), time to reach maximum plasma concentration (Tmax), area under the curve (AUC), clearance, and plasma half-life (t1/2). Subsequently, through a rigorous screening process of titles and abstracts, studies conducted in vitro or on animals, as well as those reporting pharmacokinetic data related to drugs other than GPS or language barriers, were systematically excluded. Drawing from the data and studies pertaining to this review, we conducted a thorough and informative analysis of the pharmacological characteristics and biological functions of GPS. These encompassed a wide range of effects, including hepatoprotective, anti-inflammatory, antifibrotic, antioxidant, analgesic, antitumor, and immunomodulatory properties. The analysis provided a comprehensive and insightful understanding of GPS's pharmacological profile and its diverse activities. Enhancing theoretical and experimental methodologies could prove advantageous in expanding the clinical applications of GPS. This could involve optimizing the bioavailability and pharmacokinetics of GPS, uncovering additional biomarkers and potential biotransformation pathways, and investigating its combined effects with standard-of-care medications.

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 promotes the osteogenesis of bone mesenchymal stem cells by modulation of β-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/β‐catenin pathway, effect that was inhibited using the BMP inhibitor Noggin and Wnt/β‐catenin inhibitor DKK1. Silencing the β‐catenin gene and BMP2 gene blocked the osteogenic differentiation induced by GEN in BMSCs. This block was also observed when only β‐catenin was silenced, although the knockout of BMP2 did not affect β‐catenin expression induced by GEN. Therefore, GEN promotes BMSC osteogenesis by regulating β‐catenin‐BMP signalling, providing a novel strategy in the treatment of osteoporosis.

Effects of Gentiopicroside on activation of NLRP3 inflammasome in acute gouty arthritis mice induced by MSU

Acute gouty arthritis is a self-limiting inflammatory disease resulting from the deposition of monosodium urate (MSU) crystals. It has been shown that Gentiopicroside (GPS) possesses anti-inflammatory and analgesic functions. The aim of this study was to parse out whether GPS has an effect on acute gouty arthritis. We established an acute gouty arthritis model by the injection of MSU into the paw, and found that GPS relieves MSU-induced mechanical, thermal hyperalgesia, and paw swelling. Furthermore, GPS down-regulated the release of pro-inflammatory cytokines in paw tissues, including IL-1β, IL-6, IL-18, and TNF-α. The results of H&E staining and MPO activity measurement showed that GPS inhibits neutrophil infiltration. And the over-expressions of NOD-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), and Caspase-1 induced by MSU were inhibited by treatment with GPS. These results revealed that GPS can treat acute gouty arthritis based on anti-inflammatory and analgesic properties in vivo, which might be ascribed to the inhibition on NLRP3 inflammasome. Furthermore, we performed in vitro study to confirm the results of in vivo study. Consistently, the results proved that GPS could inhibit the activation of NLRP3 inflammasome in RAW264.7 macrophages stimulated by LPS-MSU. In conclusion, this study provides an experimental basis for the application of GPS and expands the potential value of GPS in the therapy of acute gouty arthritis.

The Traditional Uses, Phytochemistry, Pharmacology, Toxicology, and Clinical Uses of Metagentiana Rhodantha (Franch.) T.N.Ho and S.W.Liu, an Ethnomedicine in Southwest China

Background: Metagentiana rhodantha (Franch.) T.N.Ho and S.W.Liu (MR) belongs to Gentianales, and it is often called Hong-hua-long-dan in Chinese. Traditionally, it has been used to cure acute icteric hepatitis, sore throat, dysentery, acute gastritis, carbuncle, and furuncle based on traditional Chinese medicine (TCM) concepts. Aim of Study: This review manages to provide a critical and comprehensive analysis on the traditional uses, phytochemistry, pharmacology, toxicology, and clinical uses of MR and to evaluate the therapeutic potential of this plant. Methods: Relevant data mainly literatures on MR were selected from available database. All the papers reviewed provided evidence that the source herbs were reliably identified. Results: The heat-clearing and removing the phlegm, and purging fire and removing toxicity of MR contribute to its dispelling jaundice, and clearing lung heat and cough. The compounds isolated from this plant include iridoids and secoiridoids, phenolic acids, ketones, triterpenoids, flavonoids, benzophenone glycosides, and others. Mangiferin (MAF) is a characteristic substance from this plant. The pharmacological studies show that some extracts and compounds from MR exhibit anti-inflammatory, antinociceptive, antibacterial, hepatoprotective, cardioprotective, and other effects which are associated with the traditional uses of this plant. The toxicological studies suggest that MAF is less toxic in mice and dogs. Nowadays, Chinese patent drugs such as Feilike Jiaonang and Kangfuling Jiaonang containing MR have been used to cure cough, asthma, chronic bronchitis, dysmenorrhea, and appendagitis. Conclusion: Although the current studies provide related research information of MR, it is still necessary to systemically evaluate the chemistry, pharmacology, toxicity, and safety of the extracts or compounds from this plant before clinical trials in the future. In addition, except for lung infection-related diseases, analgesia, anti-tumor, and hypertriglycemia may be new and prior therapeutic scopes of this ethnomedicine in the future.

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 Ameliorates the Progression from Hepatic Steatosis to Fibrosis Induced by Chronic Alcohol Intake

In current study, we aimed to investigate whether the gentiopicroside (GPS) derived from Gentiana manshurica Kitagawa could block the progression of alcoholic hepatic steatosis to fibrosis induced by chronic ethanol intake. C57BL/6 mice were fed an ethanol-containing Lieber-DeCarli diet for 4 weeks. LX-2 human hepatic stellate cells were treated with GPS 1 h prior to transforming growth factor-β (TGF-β) stimulation, and murine hepatocyte AML12 cells were pretreated by GPS 1 h prior to ethanol treatment. GPS inhibited the expression of type I collagen (collagen I), α-smooth muscle actin (α-SMA) and tissue inhibitor of metal protease 1 in ethanol-fed mouse livers with mild fibrosis. In addition, the imbalanced lipid metabolism induced by chronic ethanol-feeding was ameliorated by GPS pretreatment, characterized by the modulation of lipid accumulation. Consistently, GPS inhibited the expression of collagen I and α-SMA in LX-2 cells stimulated by TGF-β. Inhibition of lipid synthesis and promotion of oxidation by GPS were also confirmed in ethanol-treated AML12 cells. GPS could prevent hepatic steatosis advancing to the inception of a mild fibrosis caused by chronic alcohol exposure, suggesting GPS might be a promising therapy for targeting the early stage of alcoholic liver disease.

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.

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.

Gentiopicroside attenuates diabetic retinopathy by inhibiting inflammation, oxidative stress, and NF-κB activation in rat model

Diabetic retinopathy, an inflammatory condition, is one of the devastating complication associated with diabetes that can lead to irreversible blindness. Gentiopicroside (GP), a secoiridoid glycoside, exhibits anti-inflammatory and antioxidant activity. The investigation was carried out to explore whether GP could attenuate diabetic retinopathy in diabetic rats. Diabetes was induced by injecting streptozotocin (STZ) (65 mg/kg) intraperitoneally in 8-weeks-old male rats (200–240 g). The treatment group received GP (20, 40, 80 mg/kg) orally for a duration of 10 weeks in diabetic rats (n = 10), and the diabetic group animals received phosphate buffer solution (n = 20). Effect of GP on cell viability study was performed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Oxidative stress markers, inflammatory mediators, and angiogenic factors were quantified in the retinal tissues of diabetic animals. All data were analyzed by one-way analysis of variance (ANOVA) at P < 0.05. Cytoprotective effect of GP was observed in MTT assay. GP effectively downregulated inflammatory cytokine, nuclear factor κB (NF-κB), tumor necrosis factor-α (TNF-α), interleukin 1 beta (IL-1β), and intercellular adhesion molecules-1 (ICAM-1), and upregulated antioxidant markers glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) in the retina of diabetic rats. GP equilibrated the disturbed angiogenic factors in the diabetic retinal tissues. Results clearly indicated defensive role of GP in the treatment of diabetic retinopathy by inhibition of NF-κB and oxidative stress.

Ultra-diluted Toxicodendron pubescens attenuates pro-inflammatory cytokines and ROS- mediated neuropathic pain in rats

Despite the availability of multiple therapeutic agents, the search for novel pain management of neuropathic pain is still a challenge. Oxidative stress and inflammatory signaling are prominently involved in clinical manifestation of neuropathic pain. Toxicodendron pubescens, popularly known as Rhus Tox (RT) is recommended in alternative medicines as an anti-inflammatory and analgesic remedy. Earlier, we reported anti-inflammatory, anti-arthritic and immunomodulatory activities of Rhus Tox. In continuation, we evaluated antinociceptive efficacy of Rhus Tox in the neuropathic pain and delineated its underlying mechanism. Initially, in-vitro assay using LPS-mediated ROS-induced U-87 glioblastoma cells was performed to study the effect of Rhus Tox on reactive oxygen species (ROS), anti-oxidant status and cytokine profile. Rhus Tox decreased oxidative stress and cytokine release with restoration of anti-oxidant systems. Chronic treatment with Rhus Tox ultra dilutions for 14 days ameliorated neuropathic pain revealed as inhibition of cold, warm and mechanical allodynia along with improved motor nerve conduction velocity (MNCV) in constricted nerve. Rhus Tox decreased the oxidative and nitrosative stress by reducing malondialdehyde (MDA) and nitric oxide (NO) content, respectively along with up regulated glutathione (GSH), superoxide dismutase (SOD) and catalase activity in sciatic nerve of rats. Notably, Rhus Tox treatment caused significant reductions in the levels of tumor necrosis factor (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) as compared with CCI-control group. Protective effect of Rhus Tox against CCI-induced sciatic nerve injury in histopathology study was exhibited through maintenance of normal nerve architecture and inhibition of inflammatory changes. Overall, neuroprotective effect of Rhus Tox in CCI-induced neuropathic pain suggests the involvement of anti-oxidative and anti-inflammatory mechanisms.

Gentiopicroside inhibits RANKL-induced osteoclastogenesis by regulating NF-κB and JNK signaling pathways

Gentiopicroside, a main active component from the traditional Chinese herb medicine Gentiana manshurica Kitag, has been shown to possess anti-arthritis effect. However, the molecular mechanism of gentiopicroside on the osteoclast formation remains unclear. The present study was designed to investigate the effects and mechanisms of gentiopicroside on receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis. The results showed that pre-treatment with gentiopicroside significantly inhibited RANKL-induced osteoclast formation from mouse bone marrow macrophages (BMMs). In addition, we observed that gentiopicroside efficiently suppressed osteoclastogenesis-related marker genes expression in RANKL-stimulated BMMs. Mechanistically, gentiopicroside suppressed RANKL-induced the activation of JNK and NF-κB signaling pathways in BMMs. Taken together, the present study demonstrated that gentiopicroside inhibits RANKL-induced osteoclastogenesis through the inactivation of JNK and NF-κB signaling pathways. Thus, gentiopicroside may be a promising agent for the treatment of osteoporosis.