Clavine alkaloids and derivatives as mutagens detected in the Ames test.

Eight cytostatic clavines were investigated for mutagenicity in Salmonella typhimurium (reversion of the his-strains TA98, TA100, TA102 and TA1537), directly and in the presence of a mammalian xenobiotic metabolizing system, S9 (NADPH-fortified postmitochondrial fraction of liver homogenate from Aroclor 1254-treated rats). Four compounds (festuclavine, 17-bromofestuclavine, 1-allylelymoclavine and 1-methyllysergol methyl ether) were direct mutagens, whose activity was enhanced in the presence of S9. The other compounds (1-cyclopentylfestuclavine, 13-bromo-1-cyclopropylmethylfestuclavine, 6-cyano-1-propyl-6-norfestuclavine and 6-allyl-1-propyl-6-norfestuclavine) showed mutagenic effects only in the presence of S9, as previously observed with other clavines (agroclavine and its 1-propyl and 1-pentyl derivatives). Thus, all investigated clavines may be metabolized to mutagenic products by mammalian enzymes. Bacteriotoxic activities did not correlate with mutagenic activities. The bacteriotoxicity of several clavines was reduced in the presence of S9. The results are discussed with regard to the potential therapeutic use of clavine alkaloids as antimicrobial and antineoplastic agents.