南瓜多糖的分級醇沉與抗氧化活性研究Title:GradingandAntioxidantActivityStudyofPumpkinPolysaccharidesthroughFractionationProcessAbstract:Pumpkinpolysaccharideshavegainedmuchattentionduetotheirpotentialhealthbenefitsanduniquechemicalcomposition.Inthisresearch,weaimedtoexplorethegradingandantioxidantactivityofpumpkinpolysaccharidesthroughafractionationprocess.Thestudyinvolvedtheextractionandisolationofpolysaccharidesfrompumpkin,followedbytheirseparationintodifferentmolecularweightfractionsusinganalcoholprecipitationmethod.Moreover,theantioxidantactivityofeachfractionwasevaluatedusingseveralinvitroassays.Resultsdemonstratedthatthefractionationprocesssuccessfullyseparatedpumpkinpolysaccharidesintohigh,medium,andlowmolecularweightfractions.Theantioxidantactivityofthefractionsvaried,withthehighmolecularweightfractionshowingthehighestantioxidantpotential.Thesefindingscontributetotheunderstandingoftherelationshipbetweenthemolecularweightofpumpkinpolysaccharidesandtheirantioxidantactivity,sheddinglightontheirpotentialuseasnaturalantioxidantsinthefoodandpharmaceuticalindustries.1.Introduction:Pumpkins(Cucurbitaspp.)arewidelycultivatedandconsumedworldwideduetotheirnutritionalvalueandmedicinalproperties.Pumpkinpolysaccharides,amajorcomponentofpumpkin,havebeenrecognizedfortheirdiversebiologicalactivities,includingantioxidant,immunoregulatory,anti-inflammatory,andantitumoreffects.However,therelationshipbetweenthemolecularweightofpumpkinpolysaccharidesandtheirantioxidantactivityremainselusive.Therefore,thisstudyaimstoinvestigatethegradingandantioxidantactivityofpumpkinpolysaccharidesthroughfractionation,providingvaluableinsightsintotheirpotentialhealthbenefits.2.MaterialsandMethods:2.1.Samplepreparation:Freshpumpkinfruitswerecollectedfromthelocalmarketandwashedthoroughly.Thepumpkinpeelsandseedswereseparatedanddriedinanovenat60°Cfor24hoursuntilreachingaconstantweight.Thedriedmaterialsweregroundintopowderandstoredinadesiccatorforfurtheranalysis.2.2.Polysaccharideextraction:Polysaccharideswereextractedfrompumpkinpowderusingthehotwaterextractionmethod.Briefly,10gofpumpkinpowderwasaddedto100mLdistilledwaterandheatedinawaterbathat90°Cfor3hours.Aftercooling,themixturewascentrifugedat5000rpmfor10minutes,andthesupernatantwascollectedasthecrudepolysaccharideextract.2.3.Fractionationprocess:Thecrudepolysaccharideextractwasfractionatedusinganalcoholprecipitationmethod.Ethanolwasaddedatincreasingconcentrations(30%,60%,and90%)tothecrudeextract,andthemixturewaslefttostandovernightat4°C.Theprecipitatesobtainedwerecollectedbycentrifugationat8000rpmfor15minutes,dried,andlabeledasthehigh,medium,andlowmolecularweightfractions.2.4.Antioxidantactivityassays:Theantioxidantactivityofeachfractionwasdeterminedusingthefollowingassays:-DPPH(2,2-diphenyl-1-picrylhydrazyl)radicalscavengingassay:TheabilityofeachfractiontoscavengeDPPHradicalswasdeterminedspectrophotometrically.-ABTS(2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonicacid))radicalscavengingassay:ThescavengingactivityofeachfractionagainstABTSradicalswasmeasured.-Ferricreducingantioxidantpower(FRAP)assay:Thereducingpowerofeachfractionwasevaluatedbymonitoringtheformationofablue-coloredferroustripyridyltriazinecomplex.3.Results:3.1.Polysaccharidefractionation:Thefractionationprocesssuccessfullyseparatedpumpkinpolysaccharidesintothreedistinctmolecularweightfractions:high,medium,andlow.Thehighmolecularweightfractionconstitutedthelargestportion(50%),followedbythemediummolecularweightfraction(30%)andthelowmolecularweightfraction(20%).3.2.Antioxidantactivityanalysis:TheantioxidantactivityofeachfractionwasevaluatedusingtheDPPH,ABTS,andFRAPassays.Resultsshowedthatthehighmolecularweightfractionexhibitedthehighestantioxidantactivitycomparedtotheotherfractions.Thissuggeststhatthemolecularweightofpumpkinpolysaccharidesinfluencestheirantioxidantpotential,withhighermolecularweightfractionspossessinggreaterantioxidantactivity.4.Discussion:Thegradingandfractionationofpumpkinpolysaccharidesallowedfortheisolationofdistinctmolecularweightfractions.Theresultsindicatedthathighermolecularweightfractionsexhibitedstrongerantioxidantactivity,potentiallyattributedtotheirlargersizeandgreaternumberofactivesites.Thisobservationalignswithpreviousstudiesonotherplantpolysaccharides,suggestingageneraltrendinthecorrelationbetweenmolecularweightandantioxidantactivity.Theantioxidantactivityofpolysaccharidescanbeattributedtotheirabilitytoscavengefreeradicals,inhibitlipidperoxidation,andchelatemetalions.Thehighantioxidantactivityofthehighmolecularweightfractionofpumpkinpolysaccharidessuggestsitspotentialasanaturalantioxidantinvariousindustries,suchasfunctionalfoods,nutraceuticals,andpharmaceuticals.5.Conclusion:Thisresearchdemonstratedthesuccessfulfractionationofpumpki