Isolation, Chemical Structure, AcuteToxicity, andSome Physicochemical Properties ofTerritrem B'fromAspergillus terreus

Wehaveisolated ametabolite ofterritrem, designated territrem B',fromthechloroform extract ofarice culture ofAspergillus terreus 23-1byusing thesameisolation procedure asthat forterritrems A,B,andC.The present isolation procedure gaveabout 10mgofterritrem B'from4kgofrice culture perbatch. Analysis of thehigh-resolution massspectrum showed that themolecular composition ofterritrem B'isC29H34010 (found, 542.2167; required, 542.200). Someresults ofphysicochemical andacute tests arepresented inthis paper. Single-crystal X-ray diffractometry ofterritrem B'indicated that thethree-dimensional structure ofterritrem B'hasnotchanged significantly fromthatofterritrem B except fortheinsertion ofoneoxygen atominto territrem Btomakeanadditional pyronring intheEring. Thetremorgenic activity ofterritrem B'isgreatly reduced astested byintraperitoneal injection inmice. A series ofstructurally related tremorgenic metabolites, designated territrems A,B,andC (TRA,TRB,andTRC, respectively), wasisolated fromthechloroform extract ofa rice culture ofAspergillus terreus 23-1(2,4).Recently, we havesucceeded inisolating another related metabolite from thecondensed fraction Iofthechloroform extract ofthe samerice culture. Since theRfvalues ofthecompound in somethin-layer chromatography systems (Fig. 1)werebetweentheRfvalues ofTRBandTRC,thecompound was designated territrem B'(TRB'). Theprocedures forculture, clean uponasilica gelcolumn, silica gelcolumnchromatography, andthin-layer chromatography weredescribed by Lingetal.(3). Fraction Iwasconcentrated todryness bya rotation evaporator, redissolved ina minimal amountof chloroform, andprecipitated withanexcessamountof n-hexane. Thedried precipitate, about800mg fromone batch, containing TRA,TRB,andTRB'wasdissolved ina minimal amountofchloroform, applied toacolumn ofSilica Gel60,4cm(inner diameter) by29cmlong, andeluted with benzene-ethyl acetate (1:1, vol/vol) ata flowrateof1 ml/min. Eachtubecollected 20mlofeffluent, andthe compounds ineachtubeweredetected bythin-layer chromatography. Thefractions containing TRB'werepooled, dried byarotation evaporator, anddissolved inchloroformethanol (1:1, vol/vol) forcrystallization. Thesolvent forthe final recrystallizatio n waschloroform-benzene