VOL4S NO．8 THEJOURNAL OF ANTIBIOTICS ANEWIMMUNOSUPPRESSIVE CYTOCHALASINISOLATED FROMAPestalotiasp． NEALS．BURRES，UsHAPREMACHANDRAN， PATRICKE．HUMPHREY，MARIANNAJACKSON and RANDAL H．CHEN PharmaceuticalProductsDivision， ResearchandDevelopment， AbbottLaboratories， AbbottPark，Illinois60064，U．S．A． （ReceivedfbrpublicationMarch24，1992） Inthecourseofscreenlngfbrimmunomodulators Wehavediscoveredanewcytochalasinproducedin the fbrmentation broth of a Pestalotia sp．AB 1942R－114．The cytochalasin mycotoxinsinhibit glucosetransportandawidevarietyoffundamental PrOkaryotic and eukaryotic cellular processes mediated by actin microfilaments・1）compounds CloselyrelatedtocytochalasinBbindtotheglucose transporterandactin，Whilemostothercytochala－ Sinsbindpreftrentiallytoactinsites・2）cytochalasins thatbindmonomericactinuncoupleintrinsicactin ATPase activltyfrom polymerization andinhibit boththerateofpolymerizationandtheinteraction Ofactinfilamentsinsolution，reSultinglninhibition Ofcellularmotilityandchangesinmorphology・1，3，4） In addition，CytOChalasinsinterfbre withimmune function，With e鮎ctsincludinginhibition of antigen－induced B－Cell activation，5）inhibition of macrophage－lymphocyteinteractionsdurlngantlgen recognition，6）andsuppressionofthemurineinvivo allogeneic antitumor response・7）we report the discovery，lSOlation，andstructuralidentificationof a new10－Phenyl［11］cytochalasin within vitro immunosuppressantactivlty． Theknowncompounds，CytOChalasinH，ePOXy－ COmPOund，CytOChalasinU，Wereisolatedfromthe ftrmentationbrothofPestalotiasp．AB1942R－114． Thisfunguswasisolatedfromapartridgepeaplant （Cassiajbsciculata）collectedinMissouri，U．S．A．It hasbeenpreviouslyreportedthatcytochalasinsH andJ and epoxycytochalasin H are produced by Phomqpsis pa軍alli and PhomqpsLs sQjae，reSPeC－ tively．Interestlngly，bothPhomqpsisandPestalotia areplant－aSSOCiatedimperfbctfungibelonglngtOthe classCoelomycetes・8） A42－1iterstirredftrmenterwaschargedwith30 1itersofamediumconsistlngOfdextrin2％，glucose 1367 monohydrate1％，drieddistiller’s Foreman）0．5％，Primaryyeast（Univ 0・5％and CaCO30．2％．ThepH was 7．0befbresterilizationat1210Ca lhour．Inoculumfbrthefbrmenta byseeding（0．5％）mediumIofGoETZ 丘ozen（－800C）vegetativegrowth Seed culture．Incubation ofth mediumin2－1iterErlenmeyerfla at280Conarotaryshakeropera resultinggrowthwasusedat5％ ftrmenter．Durlng fbrmentation WaSCOntrOlledat220C．Agitatio airflowwasO．7vol／vol／minute a WaS maintained at O．35kg／cm2． Siliconedefbamer，XFO371（Ivanho addedinitially at O．01％ and th demand．Thefermentationwaster days．A2－1iter aliquot was used isolation work． Thewholebroth（21iters）wascen SuPernatant adsorbedin bat （Obtainedn・OmMitsubishiKaseiCo WaSWaShedina丘ittedglassfilter methanoILWater，and methanol，S activemethanoleluatewasconce under reduced pressure and trituratedwithethylacetate．The WaSPurifiedchromatographica （1×24cm，Lobar obtained 丘om E．M uslng a methanol－Water gradien 0～20 minutes，isocratic 50％ meth 20～70 minutes，linear gradien methanol．Theflow rate was5m activebandswerecollectedat31（1），3 and47（3）minutes．Final purifi achievedbyHPLCuslng5％isopr OVerSilica（0．39×30cm，WatersFLBon Compound2afk）rded crystals crystallographywasidentifiedasc Two others wereidentified us methods as cytochalasinsJ（1） ChalasinH（3）．11） Themassspectrum（DCI－NH3） （M＋H）＋atm／Z494andbyhighreso match was determined to be COrreSPOnded to the fbrmula C 494．2906）andindicated that4i cytochalasinH・Comparisono NMR data（DEPT，COSY，HMBC COnfirms their structural sim POSitions6，7and12・In4，the13c