Quercetinisaherbalflavonoidderivedfromvariousfoodsofplantoriginandplaysaroleinanti-inflammation.Althoughanumberofresearchesinthefieldhavebeendone,themechanismofanti-inflammatoryeffectofquercetinshouldbefurtherclarified.Inthepresentstudy,weinvestigatedtheeffectsofquercetinonIL-6productionbyLPS-stimulatedneutrophilsinhuman.Neutrophilswerewerepre-treatedwithquercetinatthefinalconcentrationsofrangingfrom0-80μMfor30min,ornottreated,andthenincubatedinthepresenceorabsenceoflipopolysaccharide(LPS)atafinalconcentrationof100ng/mlforindicatedtime.ThesecretionlevelofIL-6intheculturesupernatantswasassayedbyELISA,theintracellularlevelofIL-6wasdetectedbyflowcytometryandtheexpressionofIL-6mRNAwasanalyzedbyRT-PCR.TheexperimentresultsshowedthatneutrophilsculturedwithmediumorquercetinalonedidnotexpressIL-6,butLPS(100ng/ml)inducedIL-6expressionofneutrophils.However,afterpre-treatmentofneutrophilswithquercetin(40μM)for30min,theinducibleeffectsofLPSontheincreaseofIL-6secretion,intracellularIL-6levelandIL-6mRNAexpressionbyneutrophilswereabrogated.IL-6isoneoftheimportantpro-inflammatoryfactors,especiallyinearlyphageofinflammation.Thus,ourdatasuggestedthatquercetinmightexertitsanti-inflammatoryeffectthroughnegativelymodulatingpro-inflammatoryfactors,suchasIL-6.TheinhibitoryeffectsofquercetinonIL-6productionbyneutrophilsmayprovideatheoreticalbasisonfuturetherapyofinflammation.
