Salvia transsylvanica, an endemic Romanian sage, remains understudied despite co-occurrence with validated medicinal Salvia species. In this study, lfeaves and flowers were harvested weekly during flowering (May and June) and subjected to classical hydroethanolic extraction, HPLC–DAD–ESI/MSn profiling, in vitro antioxidant assays (ABTS, DPPH, FRAP), and enzyme-inhibitory screening, with multivariate analysis correlating compositional patterns with bioactivity. Rosmarinic acid dominated the pheno