*4.5. Enzyme Kinetics and Mechanism Studies*

For determination of the binding affinity of the inhibitor (Ki) to MAO-A and -B, the enzyme assays were carried out at different concentrations of kynuramine substrate (1.90 μM to 500 μM) and varying concentrations of the inhibitors/compound. The flavonoids (**1**–**6**) were tested at 0.030–0.100 μM for MAO-A and 0.100–0.500 μM for -B. The controls without inhibitor were also run simultaneously. The results were analyzed by SigmaPlot version 10 using standard double reciprocal Lineweaver-Burk plots for computing Km and Vmax values, which were further analyzed to determine the Ki values [18,36,37].
