Effect of Hordenine on Virulence Fa

Effect of Hordenine on Virulence Factors. As shown inFigure 5A, protease activity was significantly suppressed byhordenine treatment (0.5 to 1.0 mg mL−1). At 1.0 mg mL−1,approximately 61% inhibition of protease activity was observed.Resveratrol (1.0 mg mL−1), the positive control of this studyand a documented QS inhibitor, also showed inhibition of proteaseby approximately 40% (Figure 5A) without affecting cellgrowth (data not shown). The inhibitory effect of hordenine onelastase activity was shown in Figure 5B. The reduction in elastasewas concentration-dependent, with hordenine treatmentcausing a reduction in elastase of approximately 28%, 46%, and65%, respectively, compared with the DMSO control. Resveratrol(1.0 mg mL−1) treatment resulted in a 30% inhibition ofelastase activity.Different concentrations of hordenine were assessed againstpyocyanin production. As shown in Figure 5C, a significant reductionin pyocyanin was detected after treatment with hordenine.At 0.5 mg mL−1, approximately 40% reduction in pyocyaninwas detected, and at 1.0 mg mL−1, almost 80% inhibitionwas observed. When treated with resveratrol (1.0 mg mL−1), a40% reduction of pyocyanin was observed, showing similaractivity as hordenine at 0.5 mg mL−1. Hordenine also showed aconcentration-dependent reduction in the activities of rhamnolipidand alginate (Figure 5D,E). At 1.0 mg mL−1, hordenineinhibited the activities of rhamnolipid and alginate by 53% and60%, respectively. Furthermore, pyoverdine production was significantlydecreased after hordenine treatment compared with thecontrol (Figure 5F) and was reduced by 65% at a concentration of1.0 mg mL−1.