The Role of a Newly Synthesized Antimicrobial Peptide (KK)2-KWWW-NH2 in Modulating Phosphatidylinositol Monolayer Properties in the Presence of Ascorbic Acid

Ascorbic acid (AA) and its derivatives (EAA), due to their antioxidant properties, may offer potential support in acne therapy. The aim of this study was to evaluate the effect of compound P6-(KK)₂-KWWW-NH₂-in the presence of AA or EAA on the stability and organization of phosphatidylinositol (PI) monolayers. The conducted experiments showed that the monolayers were in the expanded liquid state (37.45-48.35 mN/m) or in the transitional phase between the expanded liquid and condensed states (51.06-56.82 mN/m). Compression and decompression isotherms indicated the highest flexibility for the PI + P6 system, with the compression reversibility coefficient (<i>R</i>_v) ranging from 87.34% to 97.77%, increasing with temperature in successive loops. The surface pressure vs. time dependence after compound injection into the subphase revealed a decrease in monolayer surface pressure followed by stabilization after approximately 300 s for the PI + P6 + AA and PI + P6 + EAA systems. In contrast, for the PI + P6 system at 35 °C, an increase in surface pressure was observed.