Biomimetic transformation of gentiopicroside to erythrocentaurin

Biomimetic transformation of gentiopicroside was carded out by β-glucosidase at pH 7.0 for 3 days at 37 ℃. Two products, erythrocentaurin and 5,6-dihydro-5-formyl-6-methyl-1H,3H-pyrano[3,4-c]pyran-1-one were isolated and identified by ^1H NMR, ^13C NMR, UV, IR, MS and elemental analyse. The possible mechanisms were discussed.

Gentiopicroside alleviates alcoholic fatty liver through suppression of P2X7r-Caspapse-1 pathway

Aim To investigate the protective effects of gentiopicroside （GPS） on acute alcohol-induced fatty liver.Methods Mice were treated with ethanol （5 g · kg^-11 of body weight） by gavage every 12 h for a total of three do- ses to induce acute fatty liver. GPS （40 or 80 mg · kg^-1 ） was garaged with ethanol simultaneously for three doses. Administration of GPS significantly prevented the increases of serum ALT and AST caused by ethanol, as well as se- rum and hepatic TG. Results GPS could significantly prevent ethanol-induced hepatic steatosis and necrosis by H＆E and Oil Red O staining. GPS also significantly inhibited lipogenic genes including sterol regulatory element binding transcription factor 1 （ SREBP-1 ）, fatty acid synthase （FASN） and acetyl-CoA carboxylase （ACC） in eth- anol-treated mice. Additionally, GPS possessed the ability to prevent ethanol-induced acute liver steatosis, possibly through inducing the phosphorylation of AMP-activated protein kinase （AMPK） and liver kinase B1 （LKB1）. Af- ter treatment with GPS, peroxisome proliferator-activated receptor eL （PPARoL） protein expression in mouse liver was recovered as that level of normal mice. Ethanol treatment evoked P2X7r and caspase-1 protein expression, while GPS significantly suppressed those protein expressions. GPS may be developed as a potential therapeutic can- didate for ethanol-induced hepatic steatosis and inflammation.

Gentiopicroside targets PAQR3 to activate the PI3K/AKT signaling pathway and ameliorate disordered glucose and lipid metabolism

The obstruction of post-insulin receptor signaling is the main mechanism of insulin-resistant diabetes.Progestin and adipoQ receptor 3(PAQR3),a key regulator of inflammation and metabolism,can negatively regulate the PI3 K/AKT signaling pathway.Here,we report that gentiopicroside(GPS),the main bioactive secoiridoid glycoside of Gentiana manshurica Kitagawa,decreased lipid synthesis and increased glucose utilization in palmitic acid(PA) treated HepG2 cells.Additionally,GPS improved glycolipid metabolism in streptozotocin(STZ) treated high-fat diet(HFD)-induced diabetic mice.Our findings revealed that GPS promoted the activation of the PI3 K/AKT axis by facilitating DNA-binding protein 2(DDB2)-mediated PAQR3 ubiquitinated degradation.Moreover,results of surface plasmon resonance(SPR),microscale thermophoresis(MST) and thermal shift assay(TSA) indicated that GPS directly binds to PAQR3.Results of molecular docking and cellular thermal shift assay(CETSA) revealed that GPS directly bound to the amino acids of the PAQR3 NH2-terminus including Leu40,Asp42,Glu69,Tyr125 and Ser129,and spatially inhibited the interaction between PAQR3 and the PI3 K catalytic subunit(P110α) to restore the PI3 K/AKT signaling pathway.In summary,our study identified GPS,which inhibits PAQR3 expression and directly targets PAQR3 to restore insulin signaling pathway,as a potential drug candidate for the treatment of diabetes.

Anti-inflammatory activities of gentiopicroside against iNOS and COX-2 targets

Objective: To isolate high-purity gentiopicroside from the Chinese herbal Gentiana officinalis and investigate its anti-inflammatory activity against iNOS and COX-2 targets.Methods: The purity and structures of gentiopicroside were determined by HPLC, IR, NMR, and MS. The anti-inflammatory effects of gentiopicroside were investigated by in vivo, in vitro, and molecular experiments.Results: In vitro experiment results showed that gentiopicroside inhibited nitric oxide(NO), prostaglandin E2(PGE2), and interleukin-6(IL-6) production in mouse macrophages RAW 264.7 stimulated by lipopolysaccharide. In vivo experiment found that xylene-induced mouse ear swelling was inhibited by gentiopicroside with an inhibition rate of 34.17%. Molecular docking of cyclooxygenase-2(COX-2) and inducible nitric oxide synthase(i NOS) with gentiopicroside showed that hydrogen bonds(H-bonds) were formed between the sugar fragments in gentiopicroside structure with Tyr355, Ser353, Leu352, Ser530,Arg120, and His90 of COX-2, and Glu377, Asp382, Tyr373, Tyr347, Gln263, Asn370, and Gly371 of i NOS.Thus, gentiopicroside had a lower docking score and displayed satisfactory anti-inflammatory activities.Conclusion: These results suggested that the mechanism of anti-inflammatory activity of gentiopicroside was associated with the downregulation of inflammatory cytokines, such as NO, PGE2, and IL-6, and the suppression of iNOS and COX-2. Therefore, gentiopicroside is a potential and selective iNOS and COX-2 inhibitor.

Synthesis,and anti-inflammatory activities of gentiopicroside derivatives

A series of 26 novel derivatives have been synthesized through structural modification of gentiopicroside,a lead COX-2 inhibitor.And their in vivo and in vitro anti-inflammatory activities have been investigated.The in vitro anti-inflammatory activities were evaluated against NO,PGE2,and IL-6 production in the mouse macrophage cell line RAW264.7 stimulated by LPS.Results showed that most compounds had good inhibitory activity.The in vivo inhibitory activities were further tested against xylene-induced mouse ear swelling.Results demonstrated that several compounds were more active than the parent compound gentiopicroside.The inhibition rate of the most active compound P23(57.26%)was higher than positive control drug celecoxib(46.05%)at dose 0.28 mmol-kg-1.Molecular docking suggested that these compounds might bind to COX-2 and iNOS.Some of them,e.g P7,P14,P16,P21,P23,and P24,had high docking scores in accordance with their potency of the anti-inflammatory activitiy,that downregulation of the inflammatory factors,NO,PGE2,and IL-6,was possibly associated with the suppression of iNOS and COX-2.Therefore,these gentiopicroside derivatives may represent a novel class of COX-2 and iNOS inhibitors.

Chemical fingerprint analysis of Gentianae Radix et Rhizoma by high-performance liquid chromatography

Gentianae Radix et Rhizoma(also called "Longdan" in Chinese)is commonly used for eliminating damp-heat and quenching the fire of liver and gall bladder in traditional Chinese medicine.In this study,a novel and reliable method using high-performance liquid chromatography(HPLC)was developed both for quantitative analysis of four bioactive compounds(loganic acid,swertiamarin,gentiopicroside and sweroside)and chemical fingerprint analysis of "Longdan".In quantitative analysis,four compounds showed good regressions(R^(2)>40.9987)within the test ranges and the recovery of the method was in the range 97.61-102.49%.In fingerprint analysis,ten characteristic peaks were selected to evaluate the similarities of the crude drugs,and the HPLC chromatograms of twenty samples from different regions of China showed similar patterns.The results demonstrated that the combination of the quantitative and chromatographic fingerprint analyses offered an efficient way to evaluate the quality consistency of Gentianae Radix et Rhizoma.

Changes of Secondary Metabolites and Trace Elements in Gentiana macrophylla Flowers: A Potential Medicinal Plant Part

Objective To search for the potential medicinal plant part of Gentiana macrophyllabased on changes of secondary metabolites and trace elements in the flowers of G.macrophylla.Methods HPLC was used to detect the changes of the active constituents（longanic acid,sweroside,gentiopicroside,and swertiamarin）and ICP-AES was used for mineral nutrients in G.macrophylla during flower development.And soluble sugar,starch,crude protein,hemicelluloses,cellulose,and lignin were determined.Results Biomass of flower in full bloom（D2）phase was considerable during flower development,in which the contents of longanic acid and gentiopicroside were at the highest levels with 2.65 and 2.88 times higher than those recorded in Chinese Pharmacopoeia 2010,sweroside and swertiamarin in the flowers were reaching 6.06 and 1.25 times higher than those in roots.Florescence is the most valuable stage during flower development.The concentration of Fe,Mg,K,P,and B was higher in the flowers than that in roots.The accumulation of active constituents in the plant was influenced by the contents of metabolically linked carbon and nitrogen compounds.Conclusion The secondary metabolites,mineral nutrients,and physicochemical indicators are tightly regulated by flower organ development,D2 is an important stage for both biomass and extraction of active constituents such as longanic acid.The flowers of G.macrophylla could be used as a potential medicinal plant part for longanic acid at a high level.

The Distribution,Uses,and Characteristic Components of Gentianaceae Plants in China

Extracts of Gentianaceae herbs have been widely used as food additives,teas,or medicinal remedies for various human diseases and disorders.Iridoids,secoiridoids,and analogs glycosides,mainly include gentiopicroside,sweroside,swertiamarin,and loganic acid,are the characteristic compounds found in the Gentianaceae plants.The uses of the medicinal herbs containing these secoiridoids have been described in Chinese Materia Medica.Herbal extracts containing iridoids,secoiridoids,and analogs could exert protective effects in multiple human tissues and cells.Some of these medicinal herbs have been studied using modern pharmacological means.The results indicate that they have analgesic,liver protective,anti-inflammatory,antiallergic,anti-pathogeny,and anti-bacterial functions.This review was aimed to summarize the use of Gentianaceae herbs for disease treatments and pharmacokinetic characteristics of the active compounds.In so doing,we hope to demonstrate that Gentianaceae herbs and bioactive compounds in them may have abilities to affect inflammation,hepatic metabolism and cell signaling.In addition,we would like to bring this to the attention of the field about the use and study of compounds derived from Gentianaceae herbs.