Phenolic Chemotypes of Phlomis Olivieri Across Iranian Eco‐Regions: Associations With Antioxidant Capacity and Implications for Conservation

Population-level chemophenotypic variation in Phlomis olivieri was evaluated across eight Iranian accessions by quantifying total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity, and targeted phenolic acids by HPLC. Antioxidant inhibition at 1.0 mg mL^-1 extract ranged from 17.85% (Firozkooh) to 91.22% (Kojoor). TPC spanned 20.76-96.93 mg GAE g^-1 DW and TFC 23.56-130.64 mg QE g^-1 DW, while chlorogenic acid varied from not detected to 700.41 µg g^-1 DW. Accessions with higher inhibition generally exhibited higher TPC/TFC and elevated concentrations of key acids (chlorogenic, p-coumaric, ferulic, caffeic), indicating strong associations between phenolic pools and antioxidant capacity. Principal component analysis (PCA) separated high-phenolic/high-activity accessions (e.g., Kojoor, Taleghan) from lower-phenolic/low-activity groups (e.g., Firozkooh, Damavand); PC1 was dominated by TPC/TFC and chlorogenic/caffeic acids, whereas PC2 reflected variation chiefly in salicylic acid. Multivariate analyses (correlation heatmap, PCA, clustering) resolved accessions largely by phenolic composition and antioxidant metrics, with patterns consistent with geographic origin. These findings indicate associations between phenolic profiles and location rather than genetic causation; future work integrating molecular markers and functional assays is needed to test mechanisms. Collectively, the results identify accessions with elevated phenolic content and antioxidant capacity, informing conservation and potential pharmacological exploration of P. olivieri.