Antityrosinase and antimicrobial activities of furfuryl alcohol, furfural and furoic acid

The inhibitory kinetics of furfuryl alcohol, furfural and furoic acid on mushroom tyrosinase have been investigated. The results showed that these furan compounds were reversible inhibitors of the enzyme. Furthermore, furfuryl alcohol and furfural were found to be mixed-type inhibitors while furoic acid is uncompetitive inhibitor. The inhibition constants have been confirmed and the order of the inhibiting ability was furfural > furoic acid > furfuryl alcohol. They indicate that the functional groups on the furan ring play a crucial role in the inhibition on the enzyme. In addition, it was also found that these furan compounds could inhibit the proliferation of Salmonella bacteria and Bacillus subtilis to different extents. The minimum inhibitory concentration (MIC) values of furfuryl alcohol, furfural and furoic acid against B. subtilis and S. bacteria were 0.115, 0.027, 0.015 and 0.115, 0.029, 0.009 μM, respectively. The minimum bactericidal concentration (MBC) values of that were 0.115, 0.027, 0.015 and 0.231, 0.121, 0.030 μM, respectively.