Integrated chemical and biological analysis of Astragalus aintabicus Boiss extracts using chromatographic profiling, in vitro assays, and in silico modeling

Astragalus aintabicus Boiss, an endemic and little-studied species native to Turkey, has been extensively studied for its phytochemical composition and biological activities. Various plant parts (flowers, roots and aerial parts) were subjected to sequential extraction with solvents of increasing polarity (ethyl acetate, ethanol, ethanol/water and water). Phytochemical profiling by high-performance liquid chromatography coupled with electrospray ionisation quadrupole time-of-flight mass spectrometry (HPLC-ESI-Q-TOF-MS) revealed that the aerial parts, especially those extracted with ethanol and ethanol/water, were rich in phenolic compounds and flavonoids, with vanillic acid and hyperoside identified as predominant constituents. In contrast, the flower and root extracts had a lower content of phytochemicals, with 4-hydroxybenzoic acid being the most important compound. The antioxidant potential of the extracts was evaluated using various free radical scavenging and reduction assays, with the aerial leaf extracts showing the strongest activity. Enzyme inhibition assays showed that the extracts from the aerial leaves had the strongest inhibitory effects against acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and α-amylase, while the flower extracts were more effective inhibitors of tyrosinase and α-glucosidase. Cytotoxicity tests showed a moderate anticancer potential of the extracts with IC₅₀ value between 13.01 and 141.20 μg/ml, but with limited selectivity against cancer cells (HEK-293, A549, DU-145, HELA). In silico molecular docking studies, supported by molecular dynamics (MD) simulations and MM/PBSA (molecular mechanics- Poisson–Boltzmann surface area) free energy calculations, revealed a strong binding affinity of key phytoconstituents, rutin, isoquercitrin, hyperoside and kaempferol to important therapeutic protein targets. Overall, the results suggest that A. aintabicus, especially its aerial parts, is a promising source of bioactive compounds with antioxidant, enzyme inhibitory and moderate cytotoxic properties, warranting further investigation for its potential applications in the pharmaceutical and nutraceutical sectors.