INVESTIGATION OF ANTIMICROBIAL, ANTIBIOFILM AND ANTI-QUORUM SENSING ACTIVITIES OF EXTRACTS FROM SCUTELLARIA YILDIRIMLII M. ÇİÇEK & A.E. YAPRAK

Objective: This study aims to investigate the antimicrobial, antibiofilm, and anti-quorum sensing (anti-QS) properties of extracts derived from the aerial parts of Scutellaria yildirimlii M. Çiçek & A.E. Yaprak. Material and Method: Using a liquid-liquid extraction method, petroleum ether (PEE), ethyl acetate (EAE), and aqueous (AE) sub-extracts were obtained from the total extract (TE) prepared with 80% methanol. Broth microdilution method assessed antimicrobial activity, microplate-based biofilm model and crystal violet assay assessed antibiofilm activity, and disk diffusion method assessed anti-quorum sensing activity Result and Discussion: The extracts exhibited MIC values ranging from 625 to 10000 µg/ml against the tested bacteria. Among them, the TE and PEE extracts showed the strongest antibacterial activity against both Gram-positive and Gram-negative test bacteria. Notably, only the PEE extract demonstrated antifungal activity against Candida albicans ATCC 10231, with an MIC value of 625 µg/ml, while no antifungal activity was observed for the other extracts. However, the antimicrobial effects were generally weak compared to standard antimicrobials. At a concentration of 2500 µg/ml, the biofilm inhibition percentages for AE, TE, PEE, and EAE extracts were 76.79%, 57.47%, 54.81%, and 51.09%, respectively. An anti-QS activity test, conducted based on MIC values against Chromobacterium violaceum ATCC 12472, revealed no violacein inhibition zones, indicating a lack of anti-QS activity. The test results demonstrated that S. yildirimlii possesses greater antimicrobial properties than many other Scutellaria species. This indicates that its extracts could serve as promising candidates for developing treatments against the increasing threat of antibiotic-resistant bacteria. Nonetheless, additional research is essential to thoroughly investigate and confirm the plant’s potential as a medicinal resource.