ANTIBOTULINAL PROPERTIES OF SELECTED AROMATIC AND ALIPHATIC-KETONES

Several aromatic and aliphatic ketones were tested for inhibitory acti vity against Clostridium botulinum spores and cells. Six-tenths mM 3-h eptanone, 3-hexanone, or benzophenone delayed spore germination in bot ulinal assay medium (BAM) broth at 32-degrees-C. Sporicidal activity w as observed for 1,250 mM 2,3-pentanedione, while 2-octanone, 3-octanon e, or benzophenone were effective at 2,500 mM. In general, higher conc entrations were required to inhibit vegetative cells than to prevent s pore germination. Maximum activity against vegetative cells was observ ed at 25 mM acetanisole (4'-methoxyacetophenone), 2,3-butanedione, 2,3 -pentanedione, 2-pentanone, or benzophenone, and inhibition was indepe ndent of pH. Five-tenths mM acetanisole inhibited dipicolinic acid rel ease, 100 mM reduced 20 min 80-degrees-C thermal resistance, and 5.0 m M delayed toxigenesis in BAM broth at 32-degrees-C. Furthermore, inhib itory activity of acetanisole was comparable to that observed in BAM b roth when tested in commercially prepared chicken and beef broths. The spectrum of antibotulinal activity was dependent upon carbon chain le ngth, carbonyl position, number of carbonyls, and aromaticity. The inh ibitions observed suggest that aliphatic and aromatic ketones might ha ve potential as novel antimicrobial agents.