Antimicrobial and cytotoxic evaluation of eugenol derivatives

Eugenol is the major phenolic component of clove essential oil and it has been used in medical and dental practice for its properties like analgesic, local anesthetic, and antioxidant. It is known that eugenol can denature proteins and react with cell membrane phospholipids changing their permeability and inhibiting a great number of Gram-negative and Gram-positive bacteria as well as different types of yeast. Eugenol has ever demonstrated antimicrobial properties; thus, the search for the optimization through structural changes appears to be interesting for the development of new antimicrobials. This study aimed to evaluate the antimicrobial activity and cytotoxic characteristics of eugenol analogs. From natural eugenol, 14 derivatives were obtained by typical acylation and alkylation. Their antimicrobial activity was evaluated by the broth microdilution method. The compounds were assessed against Staphylococcus aureus ATCC 19095, Enterococcus faecalis ATCC 4083, Escherichia coli ATCC29214, Pseudomonas aeruginosa ATCC 9027, Candida albicans ATCC 62342 and the following clinical isolates from the human oral cavity: C. albicans (3), C. parapsilosis C. glabrata C. lipolytica, and C. famata. Cytotoxicity against mouse embryonic fibroblast (NIH/3T3) cell line was evaluated by MTT colorimetric assay. The majority of compounds demonstrated significant antimicrobial activities. In general, the compounds presented very low or no cytotoxicity, with an inhibitory ratio lower than 50 % against NIH/3T3 cell line.