Phytochemical profiling and computational analysis highlight anabsinthin as a potential ligand of coronavirus main protease

Natural products remain an important source of diverse structures for antiviral drug development, but pinpointing and prioritizing bioactive metabolites from complex plant extracts remains challenging. We developed an integrated approach combining phytochemical analysis and computational methods to identify sesquiterpene lactones from Artemisia absinthium L. as potential candidates for interaction with the conserved coronavirus main protease (Mpro/3CLpro), a crucial target for viral replication. Using a central composite design, we optimized ultrasound-assisted extraction, followed by GC–MS and LC–MS profiling to analyze solvent-dependent phytochemical profiles. Ethanol yielded the highest extraction efficiency and enabled the enrichment of constituents tentatively assigned to absinthin/anabsinthin-type dimeric sesquiterpene lactones, followed by chromatographic purification. These compounds were assessed through molecular docking, ADMET and toxicity predictions, and 100 ns molecular dynamics simulations with trajectory-based Prime MM-GBSA calculations. X77 served as the crystallographic non-covalent reference, and nirmatrelvir was examined only as an additional MD benchmark. Both lactones were predicted to fit within the Mpro active site, with anabsinthin showing a more favorable computational profile than absinthin. Molecular dynamics simulations indicated that the anabsinthin–Mpro complex displayed lower backbone deviations, reduced residue fluctuations, and persistent interactions with key residues, including Glu166 and Gln189. Prime MM-GBSA estimates also favored anabsinthin over absinthin, although the energetic difference relative to X77 was sensitive to the sampled trajectory window. In silico pharmacokinetic and toxicity predictions suggested generally favorable early drug-like characteristics without prominent predicted toxicity alerts. This integrated workflow combining extraction optimization, phytochemical profiling, purification, and computational assessment provides a rational strategy for prioritizing natural products for further investigation. Among the compounds examined in this study, anabsinthin emerged as the most promising A. absinthium -derived lactone candidate for subsequent experimental evaluation against Mpro. However, these computational predictions require confirmation through biochemical and cellular assays before direct Mpro inhibition or antiviral activity can be established.