Selection of promising Iranian Alcea species as phenolic-rich medicinal plants based on micromorphological, phytochemical, and antioxidant traits

Abstract Reliable identification and phytochemical characterization of medicinal plants are essential for selecting suitable germplasm and developing standardized botanical materials. We investigated eight Iranian Alcea species ( A. koelzii , A. kurdica , A. lavateriflora , A. rechingeri , A. remotiflora , A. rufescens , A. schiraziana , and A. teheranica ) grown under common field conditions. Phytochemical traits were evaluated in 46 ecotypes, while SEM and HPLC studies were performed only on 14 selected ecotypes. Micromorphological features of leaves, mericarps, and seed coats were examined using scanning electron microscopy, while flower extracts were evaluated for total phenolic, flavonoid, and anthocyanin contents, antioxidant activity, and four selected phenolic compounds were determined by targeted HPLC analysis. Diagnostic micromorphological variation was observed in glandular and fascicled trichomes and seed-coat structures. Significant interspecific variation was also detected in phytochemical and antioxidant traits. Targeted HPLC analysis of the selected ecotypes detected and quantified caffeic acid, chlorogenic acid, quercetin, and rutin in the flower extracts. Total phenolic content was positively correlated with flavonoid and anthocyanin contents and FRAP activity, but negatively correlated with IC₅₀, indicating an association between phenolic accumulation and antioxidant capacity. Hierarchical clustering based on phytochemical traits separated the species into three major groups. These complementary structural and phytochemical findings may support the characterization of Alcea germplasm and help identify promising ecotypes for trait-specific cultivation and further development of standardized botanical materials.