Biochemical Diversity and Nutraceutical Potential of Medicinal Plant-Based Herbal Teas from Southwestern Türkiye

Medicinal and aromatic plants contain valuable natural compounds widely used in health, food, and cosmetics. This study compares the antioxidant capacities and phenolic compositions of tea and ethanol extracts from eight species naturally growing in Fethiye, Muğla, Türkiye. Antioxidant activity was assessed using the β-carotene bleaching method, 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺), cupric reducing antioxidant capacity (CUPRAC), and metal chelating activity. Herbal teas generally showed stronger antioxidant activity than ethanol extracts. Rosemary tea had the highest activity (2.90 µg/mL), followed by lavender (11.30 µg/mL). In metal chelating, rosemary tea exhibited a half-maximal inhibitory concentration (IC₅₀) of 9.22 µg/mL, close to ethylenediaminetetraacetic acid (EDTA). Phenolic profiling showed rosemary tea contained 30.74 mg/g rosmarinic acid and 0.74 mg/g quercetin. These results support the traditional use of southwestern Türkiye's medicinal plants and emphasize the antioxidant potential of herbal teas. Integrating ethnobotanical knowledge with phytochemical data provides a basis for functional food development, crop improvement, and conservation of local plant genetic resources. Unlike previous studies focusing on single species or limited solvent comparisons, this research simultaneously evaluates both herbal tea and ethanol extracts of eight locally grown medicinal plants, offering a unique perspective on their comparative antioxidant and phenolic diversity.