Phytochemical Profiling and Evaluation of Antioxidant, Antimicrobial, and Larvicidal Activities of the Hydroethanolic Extract of Thymus willdenowii Boiss.

ABSTRACT Thymus willdenowii ( T. willdenowii ) Boiss. is an endemic Moroccan medicinal plant whose bioactive potential remains poorly documented. This study aimed to characterize the hydroethanolic extract of T. willdenowii and evaluate its antioxidant, antimicrobial, antifungal, and insecticidal activities. Aerial parts were extracted and analyzed using qualitative and quantitative phytochemical assays and high‐performance liquid chromatography with ultraviolet detection (HPLC/UV–vis). Antioxidant activity was assessed by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. The extract yield was 22% and showed high contents of total polyphenols (148.06 mg gallic acid equivalents per gram dry weight), tannins (10.6 mg catechin equivalents per gram dry weight), and flavonoids (7.54 mg quercetin equivalents per gram dry weight). HPLC/UV–vis identified L‐histidine (15.7%), rosmarinic acid (8.3%), ascorbic acid (2.23%), catechin (1.43%), and caffeic acid (1.96%). Moderate antioxidant activity was observed (IC 50 = 0.46 mg/mL; EC 50 = 0.40 mg/mL). The extract exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli, strong antifungal activity against Candida spp. and Fusarium solani, and significant insecticidal activity against Culex pipiens larvae (LC 50 = 556 ppm; LC 90 = 1140.7 ppm). These findings highlight T. willdenowii as a promising source of bioactive natural compounds.