Lipid Profiling and Drug Repurposing of Oedogonium angustistomum , Ulothrix variabilis and Mougeotia pulchella , and Their Peptides as Antimicrobial Agents: Integrated In Vitro and In Silico Drug Discovery Approaches

In this research, in vitro and in silico drug discovery approaches were used to evaluate the antibacterial potential of a few unexplored freshwater green algae, namely Oedogonium angustistomum, Ulothrix variabilis and Mougeotia pulchella, as well as their fatty acids and peptides. In an in vitro antimicrobial assessment, the methanol and methanol crude extracts of U. variabilis significantly inhibited the growth of S. aureus and E. coli, showing inhibition zones of 14 mm and 13 mm, respectively. However, in the antifungal experiment, all extracts, except petroleum benzine, showed excellent inhibitory effects on C. albicans and F. oxysporum, with zones of inhibition ranging from 7.33 mm to 18 mm and 40.00% to 51.33%, respectively. In the minimum inhibitory concentration analysis, the methanol extract of U. variabilis effectively reduced the viability of S. aureus at a dose of 30 [Formula: see text]g/mL. Molecular docking analysis showed that 2-(S-glutathionyl) acetyl glutathione, Endomorphin-2 and APGPR enterostatin had stronger binding affinities with all microbial proteins than fatty acids, with docking scores of –8.315 kcal/mol, –8.687 kcal/mol, –8.313 kcal/mol and –7.054 kcal/mol, respectively. In the MD simulations, all hit peptide-protein complexes showed excellent binding stability, with a stable RMSD range of [Formula: see text] Å and binding strengths of up to 99% for the simulation of 200 ns. These findings suggest that the peptides identified in algae have the potential to control antimicrobial-resistant strains and opportunistic fungal pathogens. However, further research is needed to ensure the safety and efficacy of these peptide compounds in lab-to-clinical applications.