Optimized Ultrasound-Assisted Extraction Reveals Salvia transsylvanica as a Rosmarinic Acid-Rich Endemic Sage with Antioxidant Potential.

Salvia transsylvanica was investigated as a source of bioactive metabolites by optimizing hydroethanolic ultrasound-assisted extraction (UAE) and comparing it with classical preparations. A D-optimal quadratic design was applied to aerial parts to evaluate the effects of ultrasonic amplitude, extraction time, and ethanol concentration on total phenolic content (TPC) and antioxidant capacity (ABTS, DPPH), yielding models with good fit and predictive ability. The optimal conditions (24% amplitude, 12 min, 38% ethanol) were then applied to aerial parts, flowers, and leaves, affording extracts with high TPC values (up to 240 mg GAE/g extract) and antioxidant activities comparable to aqueous infusions and 70% hydroethanolic macerates, with FRAP and DPPH values above 400 mg TE/g dw. Targeted HPLC-MS analysis revealed a Salvia-typical phenolic profile dominated by rosmarinic acid (up to 20 mg/g extract), methyl rosmarinate, caffeic acid derivatives, salvianolic acid K, and flavone glycosides (luteolin-7-O-glucoside and apigenin-7-O-glucoside), with leaf extracts generally richest in phenolics and antioxidant capacity. Conversely, macerates showed superior recovery of phytosterols and tocopherols. The extracts displayed moderate, selective antibacterial effects, particularly against Staphylococcus aureus, with inhibition zones up to 4 mm for flower-based preparations. Overall, UAE emerged as an efficient, green strategy for a rapid recovery of phenolic antioxidants from S. transsylvanica, while classical maceration complements it for lipophilic constituents, supporting the valorization of this endemic sage.