Phytochemical Profile, Antioxidant, Anticholinesterase, and Antiproliferative Activities of Endemic <i>Onosma discedens</i> : In Vitro and In Silico Approaches

This study presents the first comprehensive analysis of the phytochemical profile and biological activities of root and stalk extracts from endemic Onosma discedens Hausskn. ex Bornm. (OD). The extracts of OD were analyzed by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS), and 16 phenolics, including vanillic acid (2077.1332 µg/g extract in root) and hesperidin (1185.3621 µg/g extract in stalk), were detected. In antioxidant activity tests, DPPH• radical scavenging activity of root extract (IC₅₀: 60.69 µg/mL) was found to be higher than stalk extract (IC₅₀: 95.66 µg/mL), but both extracts showed lower activity than standard antioxidants. In antiproliferative activity assays, the OD extract exhibited low cytotoxicity against MCF7 cell lines, with an IC₅₀ value exceeding 500 µg/mL. The stem extract was more effective on the butyrylcholinesterase (BChE) enzyme (IC₅₀: 546.09 ± 0.533 µg/mL) than on the acetylcholinesterase (AChE) enzyme (IC₅₀: 721.156 ± 0.410 µg/mL). When the plant is evaluated as a whole, it has a dual inhibitory effect on both cholinesterase enzymes. Molecular docking analyses confirmed the interactions of vanillic acid and hesperidin with target enzymes. As a result, it was revealed that OD, which has a rich structure in phenolic compounds and significant bioactivity due to its cholinesterase inhibitory effect, can be utilized to treat neurodegenerative illnesses like Alzheimer's.