065 | Phytochemical profile, oxidative response and antimicrobial activity of Scutellaria lateriflora extract against Staphylococcus aureus

Dionysia Amanatidou¹, Ioannis Tsamesidis^1|2, Stylaini Axipolitou², Nektaria Grammatika², Antonella Pantaleo³, Eleana Kontonasaki², Phaedra Eleftheriou¹ | ¹Department of Biomedical Sciences, International Hellenic University, Thessaloniki, Greece; ²Department of Prosthodontics, School of Dentistry, Faculty of Health Sciences, Aristotle University of Thessaloniki, Greece; ³Department of Biomedical Science, University of Sassari, Italy.

Species of the genus Scutellaria are known to be rich in flavonoids and phenolic compounds. Several species, particularly Scutellaria baicalensis, have been extensively studied for their antimicrobial activity against Staphylococcus aureus. However, limited information is available regarding the antimicrobial potential of Scutellaria lateriflora. In the present study, a methanolic extract of Scutellaria lateriflora was evaluated for its total phenolic and flavonoid content, antimicrobial activity against S. aureus, and reactive oxygen species (ROS) production. Total phenolic content was determined using the Folin–Ciocalteu method with a gallic acid (GA) calibration curve (0–350 μg/mL, A = 0.0075C+0.0265, R² = 0.990). Total flavonoid content was measured using the AlCl₃ colorimetric method with a quercetin (Q) calibration curve (0–200 μg/mL, A = 0.004C+0.0004, R² = 0.989). The extract exhibited relatively low total phenolic content (6.73±0.44 mg GAE/g dry plant) but a comparatively higher flavonoid concentration (13.5 ± 0.001 mg QE/g extract), suggesting that flavonoids constitute a major proportion of the phenolic compounds present. Significant antimicrobial activity (90% the highest tested concentration) against S. aureus was observed with MIC values around 5 μg/mL. Intracellular ROS levels did not increase compared to untreated S. aureus, suggesting maintained redox homeostasis, which may be attributed, at least in part, to the phenolic content contributing to antioxidant activity. These findings suggest that the flavonoid-rich extract of S. lateriflora exhibits notable antimicrobial activity and may represent a promising natural source of antibacterial agents maintaining the redox balance. Further studies are required to elucidate its mechanism of action and potential therapeutic applications.