Comparative Phytochemical Profiling and In Vitro Investigation of the Antioxidant and Antimicrobial Potential of Arnica montana L., Melissa officinalis L. and Capsella bursa-pastoris Medik. Extracts and Their Synergistic Combinations.

This study investigated the phytochemical composition, antioxidant potential, and antimicrobial activity of ethanolic extracts obtained from Arnica montana L., Melissa officinalis L., and Capsella bursa-pastoris Medik., as well as their ternary mixtures. Liquid chromatography coupled with mass spectrometry analysis revealed the presence of several phenolic compounds, including luteolin, apigenin, acacetin, and phenolic acids, while rutin and hyperoside were previously reported as dominant constituents in Capsella bursa-pastoris Medik. The extracts and their mixtures exhibited significant antioxidant activity in different radical scavenging and reducing power assays, with the highest activity observed for the ACM4 mixture. Antimicrobial activity was evaluated against Staphylococcus aureus and Streptococcus pneumoniae, showing inhibitory effects with minimum inhibitory concentration values ranging from below 100 mg/L for Melissa officinalis L. extracts to above 250 mg/L for Capsella bursa-pastoris Medik. extracts. These findings suggest that the phenolic compounds identified in the studied plants contribute to their antioxidant and antibacterial properties and support the potential use of these extracts and their combinations as natural sources of bioactive compounds.