Arcopilin A (compound Arcopilin A(1)) functions as an antibacterial agent with moderate inhibitory capabilities against fungal pathogens and Gram-positive bacteria, exhibiting IC 50 values of 8.9 μg/mL for KB-3-1 cells and 14 μg/mL for L929 cells. Notably, it can effectively eradicate preformed biofilms of Staphylococcus aureus. Additionally, Arcopilin A significantly boosts the efficacy of gentamicin (GM) and vancomycin (Vac), enhancing their activities by 115 and 31 times, respectively.

Arcopilin A demonstrates significant antimicrobial properties across various tests. At concentrations ranging from 15.6 to 250 μg/mL, it disrupts preformed biofilms by about 50-60% and inhibits the growth of Staphylococcus aureus at as low as 3.9 and 7.8 μg/mL. The minimum inhibitory concentrations (MIC) for Arcopilin A are 66.7 μg/mL against Bacillus subtilis DSM 10, Staphylococcus aureus DSM 346, Schizosaccharomyces pombe DSM 70572, Candida albicans DSM 1665, and Microsporum hiemalis DSM 2656, and 31.3 μg/mL for Staphylococcus aureus DSM 1104. Additionally, Arcopilin A (3.9-31.1 μg/mL) reduces the metabolic activity of biofilms in a dose-dependent manner and inhibits the growth of planktonic cells of Staphylococcus aureus DSM 1104 at concentrations of 2-7.8 μg/mL. When used in combination with GM and Vac at concentrations of 3.9-7.8 μg/mL over 24 hours, Arcopilin A enhances the efficacy of these antibiotics, lowering the MIC values of GM from 15.6 to 0.13 μg/mL and of Vac from 2 to 0.065 μg/mL, representing an increase in effectiveness by 115 times and 31 times, respectively. This synergy marks a significant boost in the potency of GM and Vac against Staphylococcus aureus DSM 1104 planktonic cells.