PHENOLIC CONTENT, ANTIOXIDANT CAPACITY AND ANTIMICROBIAL ACTIVITY OF SELECTED NATURAL EXTRACTS: A COMPARATIVE ASSESSMENT

Abstract

Natural extracts represent promising sources of bioactive compounds for sustainable formulations. The aim of this study was to comparatively evaluate seven medicinal plant extracts and a 30 % propolis extract in terms of physicochemical characteristics, total phenolic content (TPC), DPPH radical-scavenging capacity, and antimicrobial activity. Propolis exhibited the highest TPC (1120 ± 45 mg GAE/L) and antioxidant activity (91.8 ± 1.2 %), while Thymus vulgaris showed the strongest performance among the botanical extracts. TPC was strongly correlated with DPPH activity (r = 0.920; R² = 0.847; p = 0.0012). Antimicrobial assays against Escherichia coli, Staphylococcus aureus, and Candida albicans revealed the lowest MIC values for propolis, followed by T. vulgaris, with S. aureus generally showing the greatest susceptibility. Pesticide residues were below the detection limit in all tested extracts. Based on their phenolic content, antioxidant capacity, and antimicrobial activity, propolis and T. vulgaris were identified as the most promising candidates for further evaluation as functional natural ingredients in sustainable formulations.