Viscosities and densities at several temperatures from 293.15 K to 313.15K are reported for L-ascorbic acid in aqueous glucose and sucrose solutions at different concentrations. The parameters of density, viscosity co...Viscosities and densities at several temperatures from 293.15 K to 313.15K are reported for L-ascorbic acid in aqueous glucose and sucrose solutions at different concentrations. The parameters of density, viscosity coefficient B and partial molar volume are calculated by regression. The experimental results show that densities and viscosities decrease as temperature increases at the same solute and solvent (glucose and sucrose aqueous solution) concentrations, and increase with concentration of glucose and sucrose at the same solute concentration and temperature. B increases with concentration of glucose and sucrose and temperature. L-ascorbic acid is structure-breaker or structure-making for the glucose and sucrose aqueous solutions. Furthermore, the solute-solvent interactions in ternary systems of water-glucose-electrolyte and water-sucrose-electrolyte are discussed.展开更多
In the current studies a miniature silicon wafer fuel cell(FC) using L-ascorbic acid as fuel was developed. The cell employs L-ascorbic acid and air as reactants and a thin polymer electrolyte as a separator. Inductiv...In the current studies a miniature silicon wafer fuel cell(FC) using L-ascorbic acid as fuel was developed. The cell employs L-ascorbic acid and air as reactants and a thin polymer electrolyte as a separator. Inductively coupled plasma(ICP) silicon etching was employed to fabricate high aspect-ratio columns on the silicon substrate to increase the surface area. A thin platinum layer deposited directly on the silicon surface by the sputtering was used as the catalyst layer for L-ascorbic acid electro-oxidation. Cyclic voltammetry shows that the oxidation of L-ascorbic acid on the sputtered platinum layer is irreversible and that the onset potentials for the oxidation of L-ascorbic acid are from 0.27 V to 0.35 V versus an Ag/AgCl reference electrode. It is found that at the room temperature,with 1 mol/L L-ascorbic acid/PBS(phosphate buffered solution) solution pumped to the anode at 1 ml/min flow rate and air spontaneously diffusing to the cathode as the oxidant,the maximum output power density of the cell was 1.95 mW/cm2 at a current density of 10 mA/cm2.展开更多
L-ascorbic acid is a water soluble vitamin (vitamin C) widely used as an additive in foods and cosmetics. It has high instability against certain environmental factors;the main cause of its deterioration is oxidation....L-ascorbic acid is a water soluble vitamin (vitamin C) widely used as an additive in foods and cosmetics. It has high instability against certain environmental factors;the main cause of its deterioration is oxidation. Microencapsulation is an effective protection technique of L-ascorbic acid from its degradation reactions. This work is focused on the encapsulation of L-ascorbic acid by spray drying technique using sodium alginate as wall material. The microcapsules morphology was observed by scanning electron microscopy (SEM) and the encapsulation efficiency was determined by spectrophotometric analysis. Results showed that encapsulation efficiency was of 93.48% and after 30 days was of 92.55%;differences were not significant, so that the stability of L-ascorbic acid was not affected. Encapsulation yields obtained were low, at around 30%, but the microcapsules morphology obtained is spherical.展开更多
Objective:To study the effect of L-ascorbic acid supplementation on the in vitro development of buffalo embryos and evaluate the relative mRNA abundance of some pro-apoptotic,anti-apoptotic,and embryonic development-r...Objective:To study the effect of L-ascorbic acid supplementation on the in vitro development of buffalo embryos and evaluate the relative mRNA abundance of some pro-apoptotic,anti-apoptotic,and embryonic development-related genes.Methods:In experiment 1,we evaluated the effect of the addition of 0(control),50,and 100μM L-ascorbic acid to the in vitro maturation medium on the developmental competence in terms of blastocyst rate and relative mRNA abundance of some pro-apoptotic(BAX,BID),anti-apoptotic(BCL-XL,MCL1),and embryonic development(GDF9,BMP15)related genes.Based on the results,we chose 50μM as the suitable dose of L-ascorbic acid for the subsequent experiments.We further evaluated the blastocyst rates following the addition of 50μM L-ascorbic acid to the in vitro culture medium(experiment 2),and in vitro maturation and in vitro culture media(experiment 3).In all three experiments,the maturation and culture media devoid of L-ascorbic acid served as the control group.Results:The blastocyst rate after adding 50μM L-ascorbic acid to the in vitro maturation medium was significantly higher than the control group(P<0.05),whereas 100μM L-ascorbic acid exhibited a negative effect on the blastocyst rate.The blastocyst rates for embryos cultured in 50μM L-ascorbic acid in the in vitro culture medium alone and both in vitro maturation and in vitro culture media were significantly higher than their corresponding control groups(P<0.05).The relative mRNA abundance of BAX significantly decreased in blastocysts produced after the addition of 50μM L-ascorbic acid as compared with the control group(P<0.05),whereas,for MCL1,it significantly decreased in blastocysts produced after the addition of 100μM L-ascorbic acid(P<0.05).Conclusions:The supplementation of 50μM L-ascorbic acid to in vitro maturation and in vitro culture media supports in vitro embryonic development in buffaloes by improving developmental competence and altering the expression of apoptosis-related genes.展开更多
The title compound 5,6-O-（4-bromophenyl）-L-ascorbic acid （C13H11BrO6, Mr = 343.13） has been synthesized and its structure was characterized by IR, 1H NMR and single-crystal X-ray diffraction. The product is a mixt...The title compound 5,6-O-（4-bromophenyl）-L-ascorbic acid （C13H11BrO6, Mr = 343.13） has been synthesized and its structure was characterized by IR, 1H NMR and single-crystal X-ray diffraction. The product is a mixture of two diastereomer compounds （a （7S） and b （7R））. The crystal of a （7S） belongs to orthorhombic system, space group P212121 with a = 6.5362（10）, b = 7.8226（11）, c = 25.294（4） ？, V = 1293.3（3） ？3, Z = 4, Dc = 1.762 g/cm3, μ（MoKα） = 3.202 mm-1, F（000） = 688, R = 0.0235 and wR （I 〉 2σ（I）） = 0.0566. The hydrogen bonding interactions link the molecules to form a three-dimensional system. In addition, 5,6-O-（4-bromophenyl）-L-ascorbic acid （BPAA） exhibits strong free-radical scavenging activities in vitro against 2,2-diphenyl-1-picrylhy- drazyl and superoxide anion. BPAA should be investigated further as a worthy antioxidant.展开更多
A small focused library which comprised of L-AA lactone derivatives was built with a facile method.This reported method was optimized by modifying the acidity of the solvent.As a result,12 L-AA lactones were synthesiz...A small focused library which comprised of L-AA lactone derivatives was built with a facile method.This reported method was optimized by modifying the acidity of the solvent.As a result,12 L-AA lactones were synthesized.Among these lactones,lactones 8–12 were new compounds.The cytotoxicity of these synthetic compounds were investigated.展开更多
Conductive polyacrylonitrile fibers were prepared by electroless copper plating under weak alkaline conditions,with L-ascorbic acid as reducing agent.The influences of CuSO_(4)·5H_(2)O,L-ascorbic acid,2,2′-bipyr...Conductive polyacrylonitrile fibers were prepared by electroless copper plating under weak alkaline conditions,with L-ascorbic acid as reducing agent.The influences of CuSO_(4)·5H_(2)O,L-ascorbic acid,2,2′-bipyridine and K_(4)Fe(CN)_(6) concentration on the conductivity and mass gain percentage of the fibers were studied.The morphological structure of the fibers was characterized by scanning electron microscopy(SEM),and the mechanical properties of the fibers were analyzed through the mechanical property test.The results showed that the optimal reaction conditions were as follows:26 g/L CuSO_(4)·5H_(2)O,26 g/L L-ascorbic acid,12 mg/L 2,2′-bipyridine,7 mg/L K 4Fe(CN)6,and 38℃.The volume resistivity of the conductive PAN fibers prepared by the process was only 3.84×10^(-3)Ω·cm.展开更多
Western diet(rich in highly refined sugar and fat)can induce a range of metabolic dysfunctions in animals and humans,including neuroinflammation and cognitive function decline.Neuroinflammation and cognitive impairmen...Western diet(rich in highly refined sugar and fat)can induce a range of metabolic dysfunctions in animals and humans,including neuroinflammation and cognitive function decline.Neuroinflammation and cognitive impairment,two critical pathological characteristics of Alzheimer’s disease,have been closely associated with microbial alteration via the gut-brain axis.Thus,the present study aimed to investigate the influence of 2-O-β-D-glucopyranosyl-L-ascorbic acid(AA-2βG)isolated from the fruits of Lycium barbarum on preventing the high-fructose diet(HFrD)induced neuroinflammation in mice.It was found that AA-2βG prevented HFr D-induced cognitive deficits.AA-2βG also predominantly enhanced the gut barrier integrity,decreased lipopolysaccharide entry into the circulation,which subsequently countered the activation of glial cells and neuroinflammatory response.These beneficial effects were transmissible by horizontal fecal microbiome transplantation,transferring from AA-2βG fed mice to HFr D fed mice.Additionally,AA-2βG exerted neuroprotective effects involving the enrichment of Lactobacillus and Akkermansia,potentially beneficial intestinal bacteria.The present study provided the evidence that AA-2βG could improve indices of cognition and neuroinflammmation via modulating gut dybiosis and preventing leaky gut.As a potential functional food ingredient,AA-2βG may be applied to attenuate neuroinflammation associated with Western-style diets.展开更多
We studied the first oxidation product of vitamin C, the dehydro-L-ascorbic acid dimer and characterized it by infrared and Raman spectroscopies in the solid phase. The Density functional theory was used to study its ...We studied the first oxidation product of vitamin C, the dehydro-L-ascorbic acid dimer and characterized it by infrared and Raman spectroscopies in the solid phase. The Density functional theory was used to study its structure and vibrational properties. These calculations gave us a precise knowledge of the normal modes of vibration taking into account that the molecule comprises a system of five fused rings; non planar γ-lactone and furonose rings are attached to a central dioxan ring in the twisted boat conformation. The calculated harmonic vibrational frequencies are consistent with the experimental vibrational spectra. An assignment of the observed spectral features is proposed. The shift of the band located in the infrared spectrum of the ascorbic acid from 3409 cm^-1 to 3299 cml and the remarkable increase in the band intensity at 1784 cm^-1 evidences the acid decomposition into its first product, the dehydro-L-ascorbic acid. The theoretical vibrational calculations allowed us to obtain a set of scaled force constants. The nature of the different -γ-lactone, furanose and dioxan rings and their topological properties were investigated by means of natural bond orbital and Bader＇s atoms in the molecule theory, respectively.展开更多
Objective:To evaluate the alteration of chemical behavior of L-ascorbic acid(vitamin C) with metal ion(nickel) at different pH solutions in vitro.Methods:Spectra of pure aqueous solution of L-ascorbic acid(E mark) com...Objective:To evaluate the alteration of chemical behavior of L-ascorbic acid(vitamin C) with metal ion(nickel) at different pH solutions in vitro.Methods:Spectra of pure aqueous solution of L-ascorbic acid(E mark) compound and NiSO_4(H_2O)(sigma USA) were evaluated by UV visible spectrophotometer.Spectral analysis of L-ascorbic acid and nickel at various pH(2.0, 7.0,7.4 and 8.6) at room temperature of 29℃ was recorded.In this special analysis,combined solution of L-ascorbic acid and nickel sulfate at different pH was also recorded.Results:The result revealed that λ_(max)(peak wavelength of spectra) of L-ascorbic acid at pH 2.0 was 289.0 run whereas at neutral pH 7.0,λ_(max) was 29S.4 run.In alkaline pH 8.6,λ_(max) was 295.4 nm and at pH 7.4 the λ_(max) of L-ascorbic acid remained the same as 295.4 nm.Nickel solution at acidic pH 2.0 was 394.5 nm,whereas at neutral pH 7.0 and pH 7.4 were the same as 394.5 nm.But at alkaline pH 8.6,λ_(max) value of nickel sulfate became 392.0 nm.The combined solution of L-ascorbic acid and nickel sulfate(6 mg/mL each) at pH 2.0 showed 292.5 nm and 392.5 nm,respectively whereas at pH 7.0,L-ascorbic acid showed 296.5 nm and nickel sulfate showed 391.5 nm.At pH 7.4,L-ascorbic acid showed 297.0 nm and nickel sulfate showed 394.0 nm in the combined solution whereas at pH 8.6(alkaline) L-ascorbic acid and nickel sulfate were showing 297.0 and 393.5 nm,respectively. Conclusions:Results clearly indicate an altered chemical behavior of L-ascorbic acid either alone or in combination with nickel sulfate in vitro at different pH.Perhaps oxidation of L-ascorbic acid to L-dehydro ascorbic acid via the free radical(HSc*) generation from the reaction of H,ASc + Ni(Ⅱ) is the cause of such alteration of λ_(max),value of L-ascorbic acid in the presence of metal nickel.展开更多
The electroanalysis of dopamine (DA) and ascorbic acid (AA) by square wave voltammetry has been performed at a modified carbon paste electrode with macrocyclic ligand 1, 4, 8, 11-tetraazacyclotetradecane (cyclam) and ...The electroanalysis of dopamine (DA) and ascorbic acid (AA) by square wave voltammetry has been performed at a modified carbon paste electrode with macrocyclic ligand 1, 4, 8, 11-tetraazacyclotetradecane (cyclam) and monolayer of Ni (II) cyclam. In pH 7.2 buffer solutions, the electrostatic reaction of AA with di-positive monolayer shifts the oxidation potential to less positive potential, while the electrostatic repulsion of DA with the monolayer shifts the oxidation potential of DA to more positive potential. The separation between the oxidation peaks of AA and DA at the present di-positive monolayer modified electrode (252 mV) was larger than that (187 mV) at the cyclam modified electrode. In addition, the catalytic oxidation of AA by oxidized DA has been advantageously eliminated at the modified carbon paste electrode with cyclam and Ni (II) cyclam complex. Thus, the determination of DA in the presence of an excess of AA is possible with the present modified electrodes.展开更多
Coating protects substances such as L-ascorbic acid from natural processes like oxidation. In this study, L-ascorbic acid was coated by fluid bed technology. A pH-dependent polymer was used as a coating material in or...Coating protects substances such as L-ascorbic acid from natural processes like oxidation. In this study, L-ascorbic acid was coated by fluid bed technology. A pH-dependent polymer was used as a coating material in order to release L-ascorbic acid (dissolution above pH 5.5) under conditions closest to the skin’s natural condition. Different techniques were used to determine the coating (SEM and size distribution) and to evaluate the percentage of coated L-ascorbic acid and its diffusion through the skin.展开更多
The fruit of chestnut rose(Rosa roxburghii Tratt.)contains exceptionally high levels of L-ascorbic acid(AsA)(∼1762 mg/100 g fresh weight),approximately 40-fold higher than those found in sweet orange(Citrus sinensis)...The fruit of chestnut rose(Rosa roxburghii Tratt.)contains exceptionally high levels of L-ascorbic acid(AsA)(∼1762 mg/100 g fresh weight),approximately 40-fold higher than those found in sweet orange(Citrus sinensis),which is well known for its high AsA content.However,the molecular mechanisms driving such high accumulation in chestnut rose remain unclear.Here,we report that the genes R.roxburghii PECTIN METHYLESTERASE(RroxPME),D-GALACTURONATE REDUCTASE(RroxGalUR),and DEHYDROASCORBATE REDUCTASE 2(RroxDHAR2)play crucial roles in AsA accumulation in chestnut rose fruit.By comparing R.roxburghii with the closely related Rosa multiflora,which has low AsA concentrations,we identified a 545-bp insertion in the promoter of RroxGalUR.We found that TRANSPARENT TESTA GLABRA 2(RroxTTG2),a well-known key regulator of trichome development,binds to the W-box-containing inserted region of the RroxGalUR promoter as well as the promoters of RroxPME and RroxDHAR2.In contrast,in sweet orange,CsTTG2 can bind only to CsPME.Furthermore,RroxTTG2 retains its conserved role in the regulation of trichome development during early fruit development,suggesting its spatiotemporal specificity in regulating both trichome development and AsA biosynthesis.To evaluate the application value of this pathway in other species,we heterologously expressed RroxTTG2,RroxPME,RroxGalUR,and RroxDHAR2 in lettuce(Lactuca sativa L.),which increased AsA concentrations in the transgenic lines by up to 355%(an increase from approximately 2 to 10 mg/100 g fresh weight).This study provides insights into mechanisms underlying AsA accumulation in chestnut rose and the spatiotemporal transcriptional regulation of AsA biosynthesis and trichome development.展开更多
Recent studies have highlighted the effects of various stimuli on the chemical reduction of graphene oxide(GO)through green reductant L-ascorbic acid(L-AA);however,the combination of near ultraviolet(NUV)light to incr...Recent studies have highlighted the effects of various stimuli on the chemical reduction of graphene oxide(GO)through green reductant L-ascorbic acid(L-AA);however,the combination of near ultraviolet(NUV)light to increase the reduction rate has yet to be thoroughly explored.In this study,drop-casted GO films were subjected to chemical reduction through L-AA with various levels of exposure under 405 nm NUV radiation.The structure and uniformity of GO stackings that form the film were characterized through scanning electron microscopy(SEM)and wide-angle x-ray scattering(WAXS).Additionally,WAXS was used to track the removal of oxygen-containing functional groups along with Fourier-transform infrared(FT-IR)spectroscopy and x-ray photoelectron spectroscopy(XPS)as a function of L-AA and NUV light exposure times.XPS results demonstrated that the interaction between L-AA and NUV exposure has a significant effect on the reduction of films.Furthermore,the results that yielded the highest reduction(C-C bond concentration of 60.7%)were the longest L-AA and NUV light exposure times(48 hours and 3 hours,respectively).This report provides a study on the effects of NUV on the green reduction of GO films through L-AA with potential application in solar energy and chemical sensing applications.展开更多
Retinoic acid(RA)and 2-phospho-L-ascorbic acid trisodium salt(AscPNa)promote the reprogramming of mouse embryonic fibroblasts to induced pluripotent stem cells.In the current studies,the lower abilities of RA and AscP...Retinoic acid(RA)and 2-phospho-L-ascorbic acid trisodium salt(AscPNa)promote the reprogramming of mouse embryonic fibroblasts to induced pluripotent stem cells.In the current studies,the lower abilities of RA and AscPNa to promote reprogramming in the presence of each other suggested that they may share downstream pathways at least partially.The hypothesis was further supported by the RNA-seq analysis which demonstrated a high-level overlap between RA-activated and AscPNa activated genes during reprogramming.In addition,RA upregulated Glut1/3,facilitated the membrane transportation of dehydroascorbic acid,the oxidized form of L-ascorbic acid,and subsequently maintained intracellular L-ascorbic acid at higher level and for longer time.On the other hand,AscPNa facilitated the mesenchymal-epithelial transition during reprogramming,downregulated key mesenchymal transcriptional factors like Zeb1 and Twist1,subsequently suppressed the expression of Cyp26a1/b1 which mediates the metabolism of RA,and sustained the intracellular level of RA.Furthermore,the different abilities of RA and AscPNa to induce mesenchymal-epithelial transition,pluripotency,and neuronal differentiation explain their complex contribution to reprogramming when used individually or in combination.Therefore,the current studies identified a positive feedback between RA and AscPNa,or possibility between vitamin A and C,and further explored their contributions to reprogramming.展开更多
Three copper(Ⅱ),nickel and cadmium(Ⅱ)complexes,namely[Cu_(2)(μ-H2dbda)2(phen)2]·2H_(2)O(1),[Ni(μ-H2dbda)(μ-bpb)(H_(2)O)2]n(2),and[Cd(μ-H2dbda)(μ-bpa)]n(3),have been constructed hydrothermally using H4dbda(...Three copper(Ⅱ),nickel and cadmium(Ⅱ)complexes,namely[Cu_(2)(μ-H2dbda)2(phen)2]·2H_(2)O(1),[Ni(μ-H2dbda)(μ-bpb)(H_(2)O)2]n(2),and[Cd(μ-H2dbda)(μ-bpa)]n(3),have been constructed hydrothermally using H4dbda(4,4'-dihydroxy-[1,1'-biphenyl]-3,3'-dicarboxylic acid),phen(1,10-phenanthroline),bpb(1,4-bis(pyrid-4-yl)benzene),bpa(bis(4-pyridyl)amine),and copper,nickel and cadmium chlorides at 160℃.The products were isolated as stable crystalline solids and were characterized by IR spectra,elemental analyses,thermogravimetric analyses,and singlecrystal X-ray diffraction analyses.Single-crystal X-ray diffraction analyses revealed that three complexes crystallize in the monoclinic P21/n,tetragonal I42d,and orthorhombic P21212 space groups.The complexes exhibit molecular dimers(1)or 2D metal-organic networks(2 and 3).The catalytic performances in the Knoevenagel reaction of these complexes were investigated.Complex 1 exhibits an effective catalytic activity and excellent reusability as a heterogeneous catalyst in the Knoevenagel reaction at room temperature.CCDC:2463800,1;2463801,2;2463802,3.展开更多
A novel spectrofluorimetric method for the determination of L ascorbic acid is proposed. It is based on the inhibition of L ascorbic acid on the formation of 2,3 diaminophenazine, which is an oxidation product of ...A novel spectrofluorimetric method for the determination of L ascorbic acid is proposed. It is based on the inhibition of L ascorbic acid on the formation of 2,3 diaminophenazine, which is an oxidation product of o phenylenediamine catalyzed by laccase .The fluorescence (at λ ex /λ em =464 nm /530 nnm) was enhanced strongly in the presence of organic media . The mechanism of o phenylenediamine oxidation reaction catalyzed by laccase in the presence of L ascorbic acid is discussed .L ascorbic acid is determined in the ethanol, 1,4 dioxane and acetone over the linear range of 4.0×10 -7 ～1.2×10 -4 mol/L, 4.0×10 -7 ～ 8.0×10 -5 mol/L and 4.0×10 -7 ～1.0×10 -4 mol/L with a detection limit of 1.20×10 -8 mol/L,1.19×10 -8 mol/L and 1.24×10 -8 mol/L, respectively. The method has been successfully applied to the simple and rapid determination of L ascorbic acid in pharmaceuticals and milk powder.展开更多
Lysophosphatidic acid(LPA)is a pleiotropic lipid agonist essential for functions of the central nervous system(CNS).It is abundant in the developing and adult brain while its concentration in biological fluids,includi...Lysophosphatidic acid(LPA)is a pleiotropic lipid agonist essential for functions of the central nervous system(CNS).It is abundant in the developing and adult brain while its concentration in biological fluids,including cerebrospinal fluid,varies significantly(Figure 1Α;Yung et al.,2014).LPA actually corresponds to a variety of lipid species that include different stereoisomers with either saturated or unsaturated fatty acids bearing likely differentiated biological activities(Figure 1Α;Yung et al.,2014;Hernández-Araiza et al.,2018).展开更多
Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electro...Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electrocatalytic oxidations of saturated alcohols(C_(1)-C_(6))to selectively form formate using Ni Co hydroxide(Ni Co-OH)derived Ni Co_(2)O_(4)solid-acid electrocatalysts with balanced Lewis acid(LASs)and Brønsted acid sites(BASs).Thermal treatment transforms BASs-rich(89.6%)Ni Co-OH into Ni Co_(2)O_(4)with nearly equal distribution of LASs(53.1%)and BASs(46.9%)which synergistically promote adsorption and activation of OH-and alcohol molecules for enhanced oxidation activity.In contrast,BASs-enriched Ni Co-OH facilitates formation of higher valence metal sites,beneficial for water oxidation.The combined experimental studies and theoretical calculation imply the oxidation ability of C1-C6alcohols increases as increased number of hydroxyl groups and decreased HOMO-LUMO gaps:methanol(C_(1))<ethylene glycol(C_(2))<glycerol(C3)<meso-erythritol(C4)<xylitol(C5)<sorbitol(C6),while the formate selectivity shows the opposite trend from 100 to 80%.This study unveils synergistic roles of LASs and BASs,as well as hydroxyl group effect in electro-upgrading of alcohols using solid-acid electrocatalysts.展开更多
Short-chain fatty acids,metabolites produced by the fermentation of dietary fiber by gut microbiota,have garnered significant attention due to their correlation with neurodegenerative diseases,particularly Parkinson’...Short-chain fatty acids,metabolites produced by the fermentation of dietary fiber by gut microbiota,have garnered significant attention due to their correlation with neurodegenerative diseases,particularly Parkinson’s disease.In this review,we summarize the changes in short-chain fatty acid levels and the abundance of short-chain fatty acid-producing bacteria in various samples from patients with Parkinson’s disease,highlighting the critical role of gut homeostasis imbalance in the pathogenesis and progression of the disease.Focusing on the nervous system,we discuss the molecular mechanisms by which short-chain fatty acids influence the homeostasis of both the enteric nervous system and the central nervous system.We identify key processes,including the activation of G protein-coupled receptors and the inhibition of histone deacetylases by short-chain fatty acids.Importantly,structural or functional disruptions in the enteric nervous system mediated by these fatty acids may lead to abnormalα-synuclein expression and gastrointestinal dysmotility,which could serve as an initiating event in Parkinson’s disease.Furthermore,we propose that short-chain fatty acids help establish communication between the enteric nervous system and the central nervous system via the vagal nerve,immune circulation,and endocrine signaling.This communication may shed light on their potential role in the transmission ofα-synuclein from the gut to the brain.Finally,we elucidate novel treatment strategies for Parkinson’s disease that target short-chain fatty acids and examine the challenges associated with translating short-chain fatty acid-based therapies into clinical practice.In conclusion,this review emphasizes the pivotal role of short-chain fatty acids in regulating gut-brain axis integrity and their significance in the pathogenesis of Parkinson’s disease from the perspective of the nervous system.Moreover,it highlights the potential value of short-chain fatty acids in early intervention for Parkinson’s disease.Future research into the molecular mechanisms of short-chain fatty acids and their synergistic interactions with other gut metabolites is likely to advance the clinical translation of innovative short-chain fatty acid-based therapies for Parkinson’s disease.展开更多
基金Supported by the Educational Department Doctor Foundation of China(No.2000005608).
文摘Viscosities and densities at several temperatures from 293.15 K to 313.15K are reported for L-ascorbic acid in aqueous glucose and sucrose solutions at different concentrations. The parameters of density, viscosity coefficient B and partial molar volume are calculated by regression. The experimental results show that densities and viscosities decrease as temperature increases at the same solute and solvent (glucose and sucrose aqueous solution) concentrations, and increase with concentration of glucose and sucrose at the same solute concentration and temperature. B increases with concentration of glucose and sucrose and temperature. L-ascorbic acid is structure-breaker or structure-making for the glucose and sucrose aqueous solutions. Furthermore, the solute-solvent interactions in ternary systems of water-glucose-electrolyte and water-sucrose-electrolyte are discussed.
基金the National Natural Science Foundation of China (No. 30670535)the Program for New Century Excellent Talents in University (No. NCET-07-0752), China
文摘In the current studies a miniature silicon wafer fuel cell(FC) using L-ascorbic acid as fuel was developed. The cell employs L-ascorbic acid and air as reactants and a thin polymer electrolyte as a separator. Inductively coupled plasma(ICP) silicon etching was employed to fabricate high aspect-ratio columns on the silicon substrate to increase the surface area. A thin platinum layer deposited directly on the silicon surface by the sputtering was used as the catalyst layer for L-ascorbic acid electro-oxidation. Cyclic voltammetry shows that the oxidation of L-ascorbic acid on the sputtered platinum layer is irreversible and that the onset potentials for the oxidation of L-ascorbic acid are from 0.27 V to 0.35 V versus an Ag/AgCl reference electrode. It is found that at the room temperature,with 1 mol/L L-ascorbic acid/PBS(phosphate buffered solution) solution pumped to the anode at 1 ml/min flow rate and air spontaneously diffusing to the cathode as the oxidant,the maximum output power density of the cell was 1.95 mW/cm2 at a current density of 10 mA/cm2.
文摘L-ascorbic acid is a water soluble vitamin (vitamin C) widely used as an additive in foods and cosmetics. It has high instability against certain environmental factors;the main cause of its deterioration is oxidation. Microencapsulation is an effective protection technique of L-ascorbic acid from its degradation reactions. This work is focused on the encapsulation of L-ascorbic acid by spray drying technique using sodium alginate as wall material. The microcapsules morphology was observed by scanning electron microscopy (SEM) and the encapsulation efficiency was determined by spectrophotometric analysis. Results showed that encapsulation efficiency was of 93.48% and after 30 days was of 92.55%;differences were not significant, so that the stability of L-ascorbic acid was not affected. Encapsulation yields obtained were low, at around 30%, but the microcapsules morphology obtained is spherical.
基金funded by the National Agriculture Innovation Project Grant to Suresh Kumar Singla(C 2-1-(5)/2007)Manmohan Singh Chauhan(C-2067 and 075).
文摘Objective:To study the effect of L-ascorbic acid supplementation on the in vitro development of buffalo embryos and evaluate the relative mRNA abundance of some pro-apoptotic,anti-apoptotic,and embryonic development-related genes.Methods:In experiment 1,we evaluated the effect of the addition of 0(control),50,and 100μM L-ascorbic acid to the in vitro maturation medium on the developmental competence in terms of blastocyst rate and relative mRNA abundance of some pro-apoptotic(BAX,BID),anti-apoptotic(BCL-XL,MCL1),and embryonic development(GDF9,BMP15)related genes.Based on the results,we chose 50μM as the suitable dose of L-ascorbic acid for the subsequent experiments.We further evaluated the blastocyst rates following the addition of 50μM L-ascorbic acid to the in vitro culture medium(experiment 2),and in vitro maturation and in vitro culture media(experiment 3).In all three experiments,the maturation and culture media devoid of L-ascorbic acid served as the control group.Results:The blastocyst rate after adding 50μM L-ascorbic acid to the in vitro maturation medium was significantly higher than the control group(P<0.05),whereas 100μM L-ascorbic acid exhibited a negative effect on the blastocyst rate.The blastocyst rates for embryos cultured in 50μM L-ascorbic acid in the in vitro culture medium alone and both in vitro maturation and in vitro culture media were significantly higher than their corresponding control groups(P<0.05).The relative mRNA abundance of BAX significantly decreased in blastocysts produced after the addition of 50μM L-ascorbic acid as compared with the control group(P<0.05),whereas,for MCL1,it significantly decreased in blastocysts produced after the addition of 100μM L-ascorbic acid(P<0.05).Conclusions:The supplementation of 50μM L-ascorbic acid to in vitro maturation and in vitro culture media supports in vitro embryonic development in buffaloes by improving developmental competence and altering the expression of apoptosis-related genes.
基金financially supported by the Scientific Research Fund of Hunan Provincial Education Department(No.16B104)the Opening Project of Key Laboratory of Comprehensive Utilization of Advantage Plants Resources in Hunan South(No.XNZW16C01)the Scientific Research Fund of Hunan University of Science and Engineering(No.16XKY063)
文摘The title compound 5,6-O-（4-bromophenyl）-L-ascorbic acid （C13H11BrO6, Mr = 343.13） has been synthesized and its structure was characterized by IR, 1H NMR and single-crystal X-ray diffraction. The product is a mixture of two diastereomer compounds （a （7S） and b （7R））. The crystal of a （7S） belongs to orthorhombic system, space group P212121 with a = 6.5362（10）, b = 7.8226（11）, c = 25.294（4） ？, V = 1293.3（3） ？3, Z = 4, Dc = 1.762 g/cm3, μ（MoKα） = 3.202 mm-1, F（000） = 688, R = 0.0235 and wR （I 〉 2σ（I）） = 0.0566. The hydrogen bonding interactions link the molecules to form a three-dimensional system. In addition, 5,6-O-（4-bromophenyl）-L-ascorbic acid （BPAA） exhibits strong free-radical scavenging activities in vitro against 2,2-diphenyl-1-picrylhy- drazyl and superoxide anion. BPAA should be investigated further as a worthy antioxidant.
基金This work was financially supported by the National Natural Science Foundation of China(No.U0932602)the National Basic Research Program of China(973 Program No.2011CB915503).
文摘A small focused library which comprised of L-AA lactone derivatives was built with a facile method.This reported method was optimized by modifying the acidity of the solvent.As a result,12 L-AA lactones were synthesized.Among these lactones,lactones 8–12 were new compounds.The cytotoxicity of these synthetic compounds were investigated.
文摘Conductive polyacrylonitrile fibers were prepared by electroless copper plating under weak alkaline conditions,with L-ascorbic acid as reducing agent.The influences of CuSO_(4)·5H_(2)O,L-ascorbic acid,2,2′-bipyridine and K_(4)Fe(CN)_(6) concentration on the conductivity and mass gain percentage of the fibers were studied.The morphological structure of the fibers was characterized by scanning electron microscopy(SEM),and the mechanical properties of the fibers were analyzed through the mechanical property test.The results showed that the optimal reaction conditions were as follows:26 g/L CuSO_(4)·5H_(2)O,26 g/L L-ascorbic acid,12 mg/L 2,2′-bipyridine,7 mg/L K 4Fe(CN)6,and 38℃.The volume resistivity of the conductive PAN fibers prepared by the process was only 3.84×10^(-3)Ω·cm.
基金the financial support from the Key Research and Development Program of Ningxia Hui Autonomous Region of China(2021BEF02008)the National Natural Science Foundation of China(32272330)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Western diet(rich in highly refined sugar and fat)can induce a range of metabolic dysfunctions in animals and humans,including neuroinflammation and cognitive function decline.Neuroinflammation and cognitive impairment,two critical pathological characteristics of Alzheimer’s disease,have been closely associated with microbial alteration via the gut-brain axis.Thus,the present study aimed to investigate the influence of 2-O-β-D-glucopyranosyl-L-ascorbic acid(AA-2βG)isolated from the fruits of Lycium barbarum on preventing the high-fructose diet(HFrD)induced neuroinflammation in mice.It was found that AA-2βG prevented HFr D-induced cognitive deficits.AA-2βG also predominantly enhanced the gut barrier integrity,decreased lipopolysaccharide entry into the circulation,which subsequently countered the activation of glial cells and neuroinflammatory response.These beneficial effects were transmissible by horizontal fecal microbiome transplantation,transferring from AA-2βG fed mice to HFr D fed mice.Additionally,AA-2βG exerted neuroprotective effects involving the enrichment of Lactobacillus and Akkermansia,potentially beneficial intestinal bacteria.The present study provided the evidence that AA-2βG could improve indices of cognition and neuroinflammmation via modulating gut dybiosis and preventing leaky gut.As a potential functional food ingredient,AA-2βG may be applied to attenuate neuroinflammation associated with Western-style diets.
文摘We studied the first oxidation product of vitamin C, the dehydro-L-ascorbic acid dimer and characterized it by infrared and Raman spectroscopies in the solid phase. The Density functional theory was used to study its structure and vibrational properties. These calculations gave us a precise knowledge of the normal modes of vibration taking into account that the molecule comprises a system of five fused rings; non planar γ-lactone and furonose rings are attached to a central dioxan ring in the twisted boat conformation. The calculated harmonic vibrational frequencies are consistent with the experimental vibrational spectra. An assignment of the observed spectral features is proposed. The shift of the band located in the infrared spectrum of the ascorbic acid from 3409 cm^-1 to 3299 cml and the remarkable increase in the band intensity at 1784 cm^-1 evidences the acid decomposition into its first product, the dehydro-L-ascorbic acid. The theoretical vibrational calculations allowed us to obtain a set of scaled force constants. The nature of the different -γ-lactone, furanose and dioxan rings and their topological properties were investigated by means of natural bond orbital and Bader＇s atoms in the molecule theory, respectively.
基金financially supported by Defence Institute ofPhysiology and Allied Sciences,Government of India,New Delhi[grant No.TC/292/TASK-116(KDS)/DIPAS/2006]
文摘Objective:To evaluate the alteration of chemical behavior of L-ascorbic acid(vitamin C) with metal ion(nickel) at different pH solutions in vitro.Methods:Spectra of pure aqueous solution of L-ascorbic acid(E mark) compound and NiSO_4(H_2O)(sigma USA) were evaluated by UV visible spectrophotometer.Spectral analysis of L-ascorbic acid and nickel at various pH(2.0, 7.0,7.4 and 8.6) at room temperature of 29℃ was recorded.In this special analysis,combined solution of L-ascorbic acid and nickel sulfate at different pH was also recorded.Results:The result revealed that λ_(max)(peak wavelength of spectra) of L-ascorbic acid at pH 2.0 was 289.0 run whereas at neutral pH 7.0,λ_(max) was 29S.4 run.In alkaline pH 8.6,λ_(max) was 295.4 nm and at pH 7.4 the λ_(max) of L-ascorbic acid remained the same as 295.4 nm.Nickel solution at acidic pH 2.0 was 394.5 nm,whereas at neutral pH 7.0 and pH 7.4 were the same as 394.5 nm.But at alkaline pH 8.6,λ_(max) value of nickel sulfate became 392.0 nm.The combined solution of L-ascorbic acid and nickel sulfate(6 mg/mL each) at pH 2.0 showed 292.5 nm and 392.5 nm,respectively whereas at pH 7.0,L-ascorbic acid showed 296.5 nm and nickel sulfate showed 391.5 nm.At pH 7.4,L-ascorbic acid showed 297.0 nm and nickel sulfate showed 394.0 nm in the combined solution whereas at pH 8.6(alkaline) L-ascorbic acid and nickel sulfate were showing 297.0 and 393.5 nm,respectively. Conclusions:Results clearly indicate an altered chemical behavior of L-ascorbic acid either alone or in combination with nickel sulfate in vitro at different pH.Perhaps oxidation of L-ascorbic acid to L-dehydro ascorbic acid via the free radical(HSc*) generation from the reaction of H,ASc + Ni(Ⅱ) is the cause of such alteration of λ_(max),value of L-ascorbic acid in the presence of metal nickel.
文摘The electroanalysis of dopamine (DA) and ascorbic acid (AA) by square wave voltammetry has been performed at a modified carbon paste electrode with macrocyclic ligand 1, 4, 8, 11-tetraazacyclotetradecane (cyclam) and monolayer of Ni (II) cyclam. In pH 7.2 buffer solutions, the electrostatic reaction of AA with di-positive monolayer shifts the oxidation potential to less positive potential, while the electrostatic repulsion of DA with the monolayer shifts the oxidation potential of DA to more positive potential. The separation between the oxidation peaks of AA and DA at the present di-positive monolayer modified electrode (252 mV) was larger than that (187 mV) at the cyclam modified electrode. In addition, the catalytic oxidation of AA by oxidized DA has been advantageously eliminated at the modified carbon paste electrode with cyclam and Ni (II) cyclam complex. Thus, the determination of DA in the presence of an excess of AA is possible with the present modified electrodes.
文摘Coating protects substances such as L-ascorbic acid from natural processes like oxidation. In this study, L-ascorbic acid was coated by fluid bed technology. A pH-dependent polymer was used as a coating material in order to release L-ascorbic acid (dissolution above pH 5.5) under conditions closest to the skin’s natural condition. Different techniques were used to determine the coating (SEM and size distribution) and to evaluate the percentage of coated L-ascorbic acid and its diffusion through the skin.
基金supported by a National Natural Science Foundation of China grant to Q.X.(nos.32494781 and 32525008)the Key Project of Hubei Provincial Natural Science Foundation grant to Q.X.(2025AFA006)+1 种基金the Foundation of Hubei Hongshan Laboratory grants to Q.X.and X.W.(nos.2021hszd016 and 2022hsqd010,respectively)a National Natural Science Foundation of China Youth Science Fund grant to G.L.(no.32302490).
文摘The fruit of chestnut rose(Rosa roxburghii Tratt.)contains exceptionally high levels of L-ascorbic acid(AsA)(∼1762 mg/100 g fresh weight),approximately 40-fold higher than those found in sweet orange(Citrus sinensis),which is well known for its high AsA content.However,the molecular mechanisms driving such high accumulation in chestnut rose remain unclear.Here,we report that the genes R.roxburghii PECTIN METHYLESTERASE(RroxPME),D-GALACTURONATE REDUCTASE(RroxGalUR),and DEHYDROASCORBATE REDUCTASE 2(RroxDHAR2)play crucial roles in AsA accumulation in chestnut rose fruit.By comparing R.roxburghii with the closely related Rosa multiflora,which has low AsA concentrations,we identified a 545-bp insertion in the promoter of RroxGalUR.We found that TRANSPARENT TESTA GLABRA 2(RroxTTG2),a well-known key regulator of trichome development,binds to the W-box-containing inserted region of the RroxGalUR promoter as well as the promoters of RroxPME and RroxDHAR2.In contrast,in sweet orange,CsTTG2 can bind only to CsPME.Furthermore,RroxTTG2 retains its conserved role in the regulation of trichome development during early fruit development,suggesting its spatiotemporal specificity in regulating both trichome development and AsA biosynthesis.To evaluate the application value of this pathway in other species,we heterologously expressed RroxTTG2,RroxPME,RroxGalUR,and RroxDHAR2 in lettuce(Lactuca sativa L.),which increased AsA concentrations in the transgenic lines by up to 355%(an increase from approximately 2 to 10 mg/100 g fresh weight).This study provides insights into mechanisms underlying AsA accumulation in chestnut rose and the spatiotemporal transcriptional regulation of AsA biosynthesis and trichome development.
基金This work was supported by the National Nuclear Security Administration[DE-NA-0003865]National Science Foundation[1848741,HRD-1810898].
文摘Recent studies have highlighted the effects of various stimuli on the chemical reduction of graphene oxide(GO)through green reductant L-ascorbic acid(L-AA);however,the combination of near ultraviolet(NUV)light to increase the reduction rate has yet to be thoroughly explored.In this study,drop-casted GO films were subjected to chemical reduction through L-AA with various levels of exposure under 405 nm NUV radiation.The structure and uniformity of GO stackings that form the film were characterized through scanning electron microscopy(SEM)and wide-angle x-ray scattering(WAXS).Additionally,WAXS was used to track the removal of oxygen-containing functional groups along with Fourier-transform infrared(FT-IR)spectroscopy and x-ray photoelectron spectroscopy(XPS)as a function of L-AA and NUV light exposure times.XPS results demonstrated that the interaction between L-AA and NUV exposure has a significant effect on the reduction of films.Furthermore,the results that yielded the highest reduction(C-C bond concentration of 60.7%)were the longest L-AA and NUV light exposure times(48 hours and 3 hours,respectively).This report provides a study on the effects of NUV on the green reduction of GO films through L-AA with potential application in solar energy and chemical sensing applications.
基金This work was supported by the National Natural Science Foundation of China(Grant No.31671475,U1601228,31900699,and 81702445)the Strategic Priority Research Program of Chinese Academy of Sciences,No.XDA16010305+3 种基金the Key Research Program of Frontier Sciences of Chinese Academy of Sciences,No.QYZDB-SSW-SMC031the International Partnership Program of Chinese Academy of Sciences,No.154144KYSB20190034the Key Research&Development Program of Guangzhou Regenerative Medicine and Health Guangdong Laboratory(Grant No.2018GZR110104008)the Science and Technology Planning Project of Guangdong Province(Grant No.2017B030314056)。
文摘Retinoic acid(RA)and 2-phospho-L-ascorbic acid trisodium salt(AscPNa)promote the reprogramming of mouse embryonic fibroblasts to induced pluripotent stem cells.In the current studies,the lower abilities of RA and AscPNa to promote reprogramming in the presence of each other suggested that they may share downstream pathways at least partially.The hypothesis was further supported by the RNA-seq analysis which demonstrated a high-level overlap between RA-activated and AscPNa activated genes during reprogramming.In addition,RA upregulated Glut1/3,facilitated the membrane transportation of dehydroascorbic acid,the oxidized form of L-ascorbic acid,and subsequently maintained intracellular L-ascorbic acid at higher level and for longer time.On the other hand,AscPNa facilitated the mesenchymal-epithelial transition during reprogramming,downregulated key mesenchymal transcriptional factors like Zeb1 and Twist1,subsequently suppressed the expression of Cyp26a1/b1 which mediates the metabolism of RA,and sustained the intracellular level of RA.Furthermore,the different abilities of RA and AscPNa to induce mesenchymal-epithelial transition,pluripotency,and neuronal differentiation explain their complex contribution to reprogramming when used individually or in combination.Therefore,the current studies identified a positive feedback between RA and AscPNa,or possibility between vitamin A and C,and further explored their contributions to reprogramming.
文摘Three copper(Ⅱ),nickel and cadmium(Ⅱ)complexes,namely[Cu_(2)(μ-H2dbda)2(phen)2]·2H_(2)O(1),[Ni(μ-H2dbda)(μ-bpb)(H_(2)O)2]n(2),and[Cd(μ-H2dbda)(μ-bpa)]n(3),have been constructed hydrothermally using H4dbda(4,4'-dihydroxy-[1,1'-biphenyl]-3,3'-dicarboxylic acid),phen(1,10-phenanthroline),bpb(1,4-bis(pyrid-4-yl)benzene),bpa(bis(4-pyridyl)amine),and copper,nickel and cadmium chlorides at 160℃.The products were isolated as stable crystalline solids and were characterized by IR spectra,elemental analyses,thermogravimetric analyses,and singlecrystal X-ray diffraction analyses.Single-crystal X-ray diffraction analyses revealed that three complexes crystallize in the monoclinic P21/n,tetragonal I42d,and orthorhombic P21212 space groups.The complexes exhibit molecular dimers(1)or 2D metal-organic networks(2 and 3).The catalytic performances in the Knoevenagel reaction of these complexes were investigated.Complex 1 exhibits an effective catalytic activity and excellent reusability as a heterogeneous catalyst in the Knoevenagel reaction at room temperature.CCDC:2463800,1;2463801,2;2463802,3.
文摘A novel spectrofluorimetric method for the determination of L ascorbic acid is proposed. It is based on the inhibition of L ascorbic acid on the formation of 2,3 diaminophenazine, which is an oxidation product of o phenylenediamine catalyzed by laccase .The fluorescence (at λ ex /λ em =464 nm /530 nnm) was enhanced strongly in the presence of organic media . The mechanism of o phenylenediamine oxidation reaction catalyzed by laccase in the presence of L ascorbic acid is discussed .L ascorbic acid is determined in the ethanol, 1,4 dioxane and acetone over the linear range of 4.0×10 -7 ～1.2×10 -4 mol/L, 4.0×10 -7 ～ 8.0×10 -5 mol/L and 4.0×10 -7 ～1.0×10 -4 mol/L with a detection limit of 1.20×10 -8 mol/L,1.19×10 -8 mol/L and 1.24×10 -8 mol/L, respectively. The method has been successfully applied to the simple and rapid determination of L ascorbic acid in pharmaceuticals and milk powder.
基金supported by the Hellenic Foundation for Research and Innovation,HFRI,“2nd Call for HFRI Research Projects to support Faculty Members&Researchers”Project 02667 to GL.
文摘Lysophosphatidic acid(LPA)is a pleiotropic lipid agonist essential for functions of the central nervous system(CNS).It is abundant in the developing and adult brain while its concentration in biological fluids,including cerebrospinal fluid,varies significantly(Figure 1Α;Yung et al.,2014).LPA actually corresponds to a variety of lipid species that include different stereoisomers with either saturated or unsaturated fatty acids bearing likely differentiated biological activities(Figure 1Α;Yung et al.,2014;Hernández-Araiza et al.,2018).
基金the financial support from the National Natural Science Foundation of China(52172110,52472231,52311530113)Shanghai"Science and Technology Innovation Action Plan"intergovernmental international science and technology cooperation project(23520710600)+1 种基金Science and Technology Commission of Shanghai Municipality(22DZ1205600)the Central Guidance on Science and Technology Development Fund of Zhejiang Province(2024ZY01011)。
文摘Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electrocatalytic oxidations of saturated alcohols(C_(1)-C_(6))to selectively form formate using Ni Co hydroxide(Ni Co-OH)derived Ni Co_(2)O_(4)solid-acid electrocatalysts with balanced Lewis acid(LASs)and Brønsted acid sites(BASs).Thermal treatment transforms BASs-rich(89.6%)Ni Co-OH into Ni Co_(2)O_(4)with nearly equal distribution of LASs(53.1%)and BASs(46.9%)which synergistically promote adsorption and activation of OH-and alcohol molecules for enhanced oxidation activity.In contrast,BASs-enriched Ni Co-OH facilitates formation of higher valence metal sites,beneficial for water oxidation.The combined experimental studies and theoretical calculation imply the oxidation ability of C1-C6alcohols increases as increased number of hydroxyl groups and decreased HOMO-LUMO gaps:methanol(C_(1))<ethylene glycol(C_(2))<glycerol(C3)<meso-erythritol(C4)<xylitol(C5)<sorbitol(C6),while the formate selectivity shows the opposite trend from 100 to 80%.This study unveils synergistic roles of LASs and BASs,as well as hydroxyl group effect in electro-upgrading of alcohols using solid-acid electrocatalysts.
基金supported by the National Key R&D Program of China,No.2021YFC2501200(to PC).
文摘Short-chain fatty acids,metabolites produced by the fermentation of dietary fiber by gut microbiota,have garnered significant attention due to their correlation with neurodegenerative diseases,particularly Parkinson’s disease.In this review,we summarize the changes in short-chain fatty acid levels and the abundance of short-chain fatty acid-producing bacteria in various samples from patients with Parkinson’s disease,highlighting the critical role of gut homeostasis imbalance in the pathogenesis and progression of the disease.Focusing on the nervous system,we discuss the molecular mechanisms by which short-chain fatty acids influence the homeostasis of both the enteric nervous system and the central nervous system.We identify key processes,including the activation of G protein-coupled receptors and the inhibition of histone deacetylases by short-chain fatty acids.Importantly,structural or functional disruptions in the enteric nervous system mediated by these fatty acids may lead to abnormalα-synuclein expression and gastrointestinal dysmotility,which could serve as an initiating event in Parkinson’s disease.Furthermore,we propose that short-chain fatty acids help establish communication between the enteric nervous system and the central nervous system via the vagal nerve,immune circulation,and endocrine signaling.This communication may shed light on their potential role in the transmission ofα-synuclein from the gut to the brain.Finally,we elucidate novel treatment strategies for Parkinson’s disease that target short-chain fatty acids and examine the challenges associated with translating short-chain fatty acid-based therapies into clinical practice.In conclusion,this review emphasizes the pivotal role of short-chain fatty acids in regulating gut-brain axis integrity and their significance in the pathogenesis of Parkinson’s disease from the perspective of the nervous system.Moreover,it highlights the potential value of short-chain fatty acids in early intervention for Parkinson’s disease.Future research into the molecular mechanisms of short-chain fatty acids and their synergistic interactions with other gut metabolites is likely to advance the clinical translation of innovative short-chain fatty acid-based therapies for Parkinson’s disease.
