LC–MS/MS Analysis, Molecular Docking, DFT Investigation, and Antioxidant Properties of Amphoricarpos praedictus

This study aimed to investigate the antioxidant activities of ethanol extracts from the flower, stem, and leaf parts of Amphoricarpos praedictus using both in silico and in vivo methods. Secondary metabolites were identified by LC-MS/MS, while total phenolic content (TPC), total flavonoid content (TFC), DPPH radical scavenging activity, FRAP, and CUPRAC reducing capacities, as well as total antioxidant status (TAS) and total oxidant status (TOS) levels, were measured spectrophotometrically. LC-MS/MS analysis identified quinic acid, protocatechuic acid, chlorogenic acid, rutin, hesperidin, and apigenin as the active secondary metabolites. Antioxidant activity showed a strong correlation with the higher phenolic and flavonoid content of the extracts. Density functional theory (DFT) calculations indicated that quinic acid is the most stable molecule, whereas rutin is the most reactive. Molecular docking revealed that fumaric acid exhibited the strongest interactions with key amino acid residues. To validate the docking results, MM-GBSA calculations were performed, demonstrating that rutin had the most negative binding free energies for both proteins (-51.324 kcal/mol for 1Q41 and -38.340 kcal/mol for 4UND). Overall, A. praedictus contains significant amounts of secondary metabolites and exhibits strong potential as a natural source of antioxidants.