Fig. 6: Kaempferol-colistin combination treatment or its individual components do not increase membrane permeability in A. baumannii.

a Combination of sub-MIC amounts of colistin (1.22 μg/ml) and kaempferol (0.375 mM), or kaempferol (0.375 mM) or colistin (1.22 μg/ml) alone, do not increase NPN uptake in A. baumannii cells, and thus do not increase the permeability of the outer membrane. High amounts of colistin (16 µg/mL) permeabilize the outer membrane. b Combination of sub-MIC amounts of colistin (1.22 μg/ml) and kaempferol (0.375 mM), or kaempferol (0.375 mM) or colistin (1.22 μg/ml) alone, do not increase PI uptake in A. baumannii cells, and thus do not increase the permeability of the inner membrane. High amounts of colistin (16 µg/mL) permeabilize the inner membrane. All assays were carried out in biological triplicate, with three technical repeats. For both panels, DMSO (the kaempferol carrier) was added to all experiments where cells were treated with colistin only. Analysis consisted of one-way ANOVA between the treated samples and the colistin (16 µg/mL) control. Average values ± S. D. are represented. Significance is indicated as ns non-significant, *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001, ****p ≤ 0.0001.