| Lycium barbarum L.was first published in"Shen Nong’s Classic of Materia Medica".It is a traditional Chinese medicine commonly used in our country,which also regarded as a functional food.In recent years,with continuous research on L.Barbarum,it has been found that L.Barbarum contains polysaccharides（LBPs）,betaine,phenols,carotenoids,and many other active ingrediets,and has a variety of physiological and pharmacological activities,including immune-enhancement,anti-oxidation,anti-tumor,anti-bacterial,neuroprotection and other effects.2-O-β-D-Glucopyranosyl-L-ascorbic acid（AA-2βG）,a novel stable ascorbic acid（AA）analogue first purified from L.Barbarum,is contained in the dried L.Barbarum fruit in about 0.5%.Previous studies have shown that AA-2βG extracted from L.Barbarum exerts antioxidant,anti-tumor and immunomodulatory physiological effects.In addition,a growing body of evidence that dietary ingredients can alter the structure of gut microbiota,which subsequently have a significant impact on host health.AA-2βG,as a natural AA analogue,its effects on gut microbiota is still rarely reported at present.Therefore,in this study,L.Barbarum was utilized as the raw material in the present study,and AA-2βG was isolated,purified,identified,and combined with animal model to study its anti-inflammatory activity and its effects on gut microbiota.This study provides a new scientific basis for revealing the anti-inflammatory mechanism of L.Barbarum,and provides a valuable theoretical basis for the application of AA-2βG as a stable AA derivative in the fields of medicine,food and health products.The results of the study are as follows:1.Extraction,purification,and structural identification of AA-2βGIn this section,the dried fruits of L.barbarum were extracted with 30%（v/v）aqueous ethanol solution.The resulting extracts were concentrated,and the residue was then purified by Dowex 1-X8 anion exchange resin column.The anion-exchange resin purified fractions were purified by AKTA semi-preparative chromatography（YMC-Pack ODS-A C18 column）to obtain higher purity fractions（99%）.Combined with the data of HPLC,matrix-assisted laser desorption ionization time-of-flight mass spectrometry（MALDI-TOF-MS）,nuclear magnetic resonance（NMR）spectrometry(1H-and 13C-NMR)and the related reports,the purified component was identified as AA-2βG.2.2-O-β-D-glucopyranosyl-L-ascorbic acid（AA-2βG）modulates gut microbiota and palliates colitis in dextran sodium sulfate-induced colitis in C57BL/6J mice.In this chapter,the effects of AA-2βG on the amelioration of colitis C57BL/6J mice induced with dextran sodium sulfate（DSS）and the modulating of gut microbiota were investigated.The results revealed that AA-2βG was demonstrated to have a mitigating therapeutic effect on IBD by various physical signs restoration（body weight,solid fecal weight and colon length were increased,and DAI score was decreased）.The concentration and the m RNA expression levels of pro-inflammatory cytokines（IL-6,IFN-γand TNF-α）were decreased by the treatment with AA-2βG.Also,AA-2βG showed intestinal anti-inflammatory effects,evidenced by promotion of the intestinal barrier function by histological and immunofluorescence analysis（proteins including ZO-1,Occludin and Claudin-1 were increased）.Moreover,the key bacteria related to IBD were found to be Porphyromonadaceae,Prevotellaceae,Rikenellaceae,Parasutterella,Parabacteroides,and Clostridium using 16S r RNA.The current results indicated that AA-2βG might treat IBD through the regulation of gut microbiota,suggesting that AA-2βG has the potential to be used as a dietary supplement in IBD.3.AA-2βG ameliorates high fructose-induced neuroinflammation in mice through regulating gut microbiota and improving intestinal barrier.In this section,the effect of AA-2βG on neuroinflammation will be evaluated by mice model of neuroinflammation induced by high fructose diet.Here,our data indicated that AA-2βG prevented HFrD-induced cognitive deficits in Morris water maze（MWM）test.In the brain,AA-2βG alleviated neuron loss or damage,countered the activation of glial cells（microglia and astrocytes）and neuroinflammatory response（upregulation of pro-inflammatory mediators m RNA expression）.AA-2βG could significantly inhibit HFrD-induced loss of MUC1 and tight junction protein,decreased plasma FITC-Dextran concentration,and enhanced the gut barrier integrity.AA-2βG also predominantly decreased lipopolysaccharide（LPS）entry into the circulation,and decreased systemic inflammation.Additionally,AA-2βG intervention significantly modulated gut dysbiosis in HFrD mice through elevating the relative abundance of Lactobacillus and Akkermansia while reducing the abundance of Alistipes using16S r RNA analysis.Further,the neuroprotective effects of AA-2βG were gut microbiota dependent,at least in part,as proved by broad-spectrum antibiotic intervention experiment.Thus,all these findings thus elucidated that AA-2βG possibly contributed to the inhibition of hippocampal neuroinflammation in HFrD-fed mice via modulating gut microbiome and preventing leaky gut.4.Effects of fecal bacteria transplantation on high-fructose-induced neuroinflammation in mice.In this chapter,horizontal fecal transferred from HFrD mice and AA mice are respectively referred as HFrD receivers（HFD→HFD）and AA receivers（AA→HFD）by using fecal transplantation technology.After 8-week of colonization,horizontal fecal transfer from AA-2βG mice（AA→HFrD）demonstrated similar cognitive protective effects as observed in the AA group mice.Fecal transplantation of AA-2βG also predominantly enhanced the gut barrier integrity,decreased plasma FITC-Dextran concentration,decreased lipopolysaccharide（LPS）entry into the circulation,which subsequently countered the activation of glial cells（microglia and astrocytes）and neuroinflammatory response（upregulation of pro-inflammatory mediators m RNA expression）.Additionally,in line with the AA group,fecal transfer from the AA group（AA→HFrD）also displayed an increased in relative abundances of Lactobacillus genus and Akkermansia＿muciniphila species,indicating that FMT from AA group recapitulated microbial as observed in their donor mice.In general,these neuro-protection effects are transmissible to HFrD-fed mice through horizontal feces transplantation,indicating that the effects of AA-2βG mediated by the gut microbiota and its subsequently effects on the host cognitive. |
