Figure 9.

Effects of pterostilbene in the activity of wild type (WT)–New Delhi metallo‐β‐lactamase‐1 (NDM‐1) and its mutants. Pterostilbene was added to assay buffer in a 96‐well plate to reach the final concentrations of 4, 8, 16, and 32 μg·ml⁻¹ and pre‐incubated with the purified WT–NDM‐1 enzyme and its mutants Trp93Ala and Asp124Ala for 10 min. Then 25‐μM nitrocefin was added for another incubation at 37°C for 30 min. The absorbance of each sample was read at 492 nm by a microplate reader at room temperature, and residual activity was calculated as described in Figure 2. All data are mean ± SD, n = 5. * P < .05, significantly different from the positive control group; one‐way ANOVA followed by a Dunnett t test