Exploring the Bioactive Properties of Thymus kotschyanus var. kotschyanus and Endemic Thymus brachychilus: From Plant Extracts to Alginate Film Formulations for Wound Infection Management

Background/Objectives: Antibiotic resistance poses significant challenges to the treatment of infectious diseases. Wounds occur as a result of damage to the skin caused by various factors and may become life-threatening with the development of infection. Plants can exhibit considerable microbiological activity due to their rich phytochemical composition. Thymus kotschyanus var. kotschyanus and the endemic species Thymus brachychilus collected from Adıyaman Province, Türkiye, have been widely used by local communities for their therapeutic properties and other purposes. Methods: In this study, ethanol extracts of these plants were prepared and evaluated for their antimicrobial activity against nine Gram-negative bacteria, seven Gram-positive bacteria, one mycobacterial strain, and four yeast strains using agar well diffusion and microdilution methods. Their antibiofilm activity was assessed using a microplate-based assay, anti-quorum sensing activity was evaluated using Chromobacterium violaceum strains, anti-infective activity was investigated using the Caenorhabditis elegans model, and cytotoxicity was evaluated using the MTT assay. The phytochemical composition of the extracts was determined by HPLC-DAD. Alginate film formulations containing the extracts were prepared using the solvent-casting method and characterized by FTIR spectroscopy and light microscopy. Their antimicrobial and antibiofilm activities were subsequently evaluated. Results: Both extracts exhibited antimicrobial, antibiofilm, anti-quorum sensing, and anti-infective activities, while no cytotoxic effects were observed. Rosmarinic acid was identified as the major compound in both extracts. The extract-loaded alginate films exhibited antimicrobial and antibiofilm activities and showed no cytotoxic effects. Conclusions: These findings suggest that alginate film formulations may be a promising approach for the topical application of T. kotschyanus var. kotschyanus and T. brachychilus extracts. In particular, the alginate films containing both plant extracts may have potential as wound dressing materials for preventing wound infections or supporting the treatment of infected wounds.