Figure 3.

The inhibition of MAO-A (a) or MAO-B (b) activity by phenolic dietary compounds. The inhibition screening for oxidative deamination of kynuramine with MAO-A (a) or MAO-B (b) was conducted with kynuramine (10 µM) incubated with either enzyme (0.01 mg/mL) and one of these phenolic dietary compounds. Concentrations tested: curcumin 140μM, guaiacol 435μM, isoeugenol 110μM, pterostilbene 270μM, resveratrol 94μM, and zingerone 51μM. The numbers are expressed as means ± SD; ∗ indicates that the significant differences were analyzed between the control (no inhibitor) and phenolic compounds. Absent bars indicate that the formation of 4-hydroxyquinoline was below the quantification limit.