Potentiation of the antibiofilm effect of natural compound analogs in a marine bacterium by the cell permeabilization mechanism

The potentiation of the anti-adhesion and anti-biofilm effects of the three compounds (OB1, AS194, AS162) was evaluated in this study. This potentiation is demonstrated by the combination of each of the three compounds with molecules of permeabilizing types which are Polymyxin B nanopeptide hydrochloride (PMBN), Phenylalanine-Arginine Beta-Naphthylamide (PAßN) and Carbonyl cyanide chlorophenylhydrazone (CCCP). The association of this type of molecule with antibiofilm compounds showed a synergistic effect in TC14. This effect was more pronounced with CCCP (5µM). Thus, the AS162 having the highest effect between the three compounds previously induced a reduction in adhesion of up to 30.80% at only 10µM. In combination with the CCCP and at the same concentration, AS162 reduces TC14's adherence by up to 11.23%, a reduction of more than 63.53%. The AS162 also reduces the biofilm mass of the same bacterium to 10.15% in the presence of CCCP, i.e. a reduction of 89.75%. When taking the case of compounds with relatively low anti-biofilm effect such as OB1 and AS194, the reduction rate under the effect of the combinations is found to be higher than that of AS162. Thus, OB1 with an EC50 of 75.39 µM when used alone, in the presence of the CCCP, experiences a reduction of this EC50 up to 3.6 µM, i.e. 95.22% reduction. In AS194 (with a relatively stronger effect than OB1), the EC50 is reduced by 74.02% and 52.79% for AS162. This method has been shown to be effective in enhancing the anti-biofilm effect of the compounds. It is therefore important to note that the less active the compound, the greater the synergistic effect with the permeabilizers.