Comprehensive Phytochemical Profiling and Antioxidant Assessment of Rhinanthus serotinus subsp. aestivalis: GC-MS and HPLC-DAD Analysis of Volatile and Phenolic Compounds in Leaf and Flower Tissues

This study represents the first comprehensive phytochemical characterization of Rhinanthus serotinus subsp. aestivalis, an understudied hemiparasitic species from the Orobanchaceae family. Using GC-MS and HPLC-DAD analyses, volatile and phenolic compound profiles were determined in leaf and flower extracts, along with antioxidant capacity evaluation via FRAP and CUPRAC assays. GC-MS analysis identified 16 volatile compounds, with matsutake alcohol (1-octen-3-ol) as the predominant constituent at exceptionally high concentrations (68.42% in flowers, 38.34% in leaves), significantly exceeding levels reported in related species. HPLC analysis revealed distinct tissue-specific phenolic profiles, with leaves demonstrating superior total phenolic content (7.26±0.28 mg GAE/g) and antioxidant capacity compared to flowers. Notable compounds included rutin (828.69 ppm), rosmarinic acid (594.16 ppm), and ascorbic acid (289.89 ppm) in leaves, while flowers were enriched in trans-caffeic acid (459.07 ppm) and pyrogallol (1062.84 ppm). These findings establish R. serotinus subsp. aestivalis as a promising source of bioactive compounds with potential applications in natural product development, functional foods, and pharmaceutical research, while providing fundamental data for future pharmacognostic studies.