Synthesis and antimicrobial activity of geranyloxy- and farnesyloxy-acetophenone derivatives against oral pathogens

The compounds 2',6'-dihydroxy-4'-geranyloxyacetophenone (1) and 2',6'-dihydroxy-4'-farnesyloxy-acetophenone (2) are oxyprenylated secondary metabolites extracted from plants belonging to the Rutaceae family. In this study, 1 and 2 were synthesized and tested for their antimicrobial activity toward major oral pathogens. Compounds 1 and 2 were synthesized by selective prenylation of 2,4,6-trihydroxyacetophenone at the 4' position with geranyl and farnesyl bromide, respectively. Compound 1 showed stronger antimicrobial activity than 2 against major oral pathogens, including Gram positive bacteria (Streptococcus mutans, Streptococcus sobrinus), Gram negative bacteria (Prevotella intermedia, Porphyromonas gingivalis) and Candida albicans. Evidences were obtained that the mode of action of 1 and 2 may be related to their iron-chelating property. This study suggests that 1 and 2 may represent potential natural molecules for the prevention/treatment of common oral infections, including dental caries, periodontal disease, and candidiasis.