Inhibitory effect of 4-ethylcatechol on β-glucuronidase activity

The inhibition of the β-glucuronidase activity of the intestinal microbiota could contribute to reducing the risk of colon cancer. This study aimed to investigate the effect of alkyl catechols, which are found in fermented foods and wood smoke utilized in food preservation, on β-glucuronidase activity. In this regard, 65.5% inhibition of β-glucuronidase activity was demonstrated by 4-ethylcatechol (4EC) at 20 μM. The concentration of 4EC, which led to 50% loss of the enzyme activity was 7.57 μM. In addition, a kinetic study was conducted on β-glucuronidase inhibition by 4EC through Lineweaver-Burk analysis and the kinetic profile proposed that 4EC is a competitive inhibitor of β-glucuronidase. Analysis of the structure-activity relationship revealed the importance of the ethyl moiety and catechol structure of 4EC for the β-glucuronidase inhibitory activity.