Comparative phytochemical and bioactivity studies on two related <i>Scorzonera </i>L. species: A chemotaxonomic contribution

Scorzonera L. (Asteraceae) is considered a taxonomically difficult genus with its more than 160 species. Scorzonera bella (SB) and S. veratrifolia (SV) species have been treated as synonyms since 1975. Recent botanical studies suggested the separation of the two taxa based on phenetic dissimilarities. Isolation, LC-MS/MS (including 53 phytochemicals as standard), and GC-MS (followed by library search) analyzes were conducted on the aerial parts of the plants to compare their phytochemical compositions and contribute to the classification of the two taxa. While flavonoid profile of SB was dominated by flavones, the majority of SV consisted of flavonols, among the analyzed standards. Nicotiflorin, the most abundant compound of SV, was the most notable difference which was not determined in SB. Kaempferol glycosides might be chemotaxonomic markers for the classification at subgenus levels. Caffeoylquinic acid esters were in common and similar amounts according to profiling and isolation results. Phytochemical compositions of nonpolar fractions of the plants differed significantly in phthalic acid esters, ursane, and hopane type triterpenoids which were only determined in SV. Phytochemical findings supported the separation of the two taxa. Antioxidant, anti-diabetic, anti-Alzheimer, and anti-hyperpigmentation potentials of the plants were evaluated in-vitro.