Synthesis and biological activity of alpha-methylene-gamma-lactones as newaroma chemicals

Seven kinds of alpha -methylene-gamma -lactones with an alkyl group at the C-4 position were synthesized according to a previously described method, w ith yields of 28-34%. These alpha -methylene-gamma -lactones had characteri stic and unique odors. All alpha -methylene-gamma -lactones added a roast-l ike odor to materials. The antimicrobial effects of alpha -methylene-gamma -lactones were investigated by using a paper disk diffusion method. The res ults showed the alpha -methylene-gamma -lactones inhibited the growth of th ree bacteria (Staphylococcus aureus, Escherichia coli, and Pseudomonas fluo rescens) and two fungi (Saccharomyces cerevisiae and Aspergillus niger). In particular, alpha -methylene-gamma -undecalactone and alpha -methylene-gam ma -dodecalactone exhibited potent inhibition of the growth of these microo rganisms compared to butyl p-hydroxybenzoate as standard antibiotic. The um u test revealed that the alpha -methylene-gamma -lactones suppressed the SO S-inducing activity of three mutagens, furylfuramide, UV irradiation and Tr p-P-1, respectively. The antimicrobial effects and the suppressive effects of SOS induction by alpha -methylene-gamma -lactones had a tendency to inte nsify as the number of carbons in the side chain increased.