Phytochemical profiling, antioxidant and enzyme inhibitory activities of Lamium purpureum with molecular insights into luteolin

Abstract Lamium purpureum ( L. purpureum ) is a medicinal plant rich in phenolic compounds. Among the identified phenolic constituents, luteolin was one of the most abundant compounds, warranting further investigation of its potential relevance to the biological activity of the ethanol extract. This study evaluated the extract through LC–MS/MS profiling, antioxidant assays, enzyme inhibition, and molecular docking. LC–MS/MS analysis identified luteolin (12,398.90 µg/L in the analyzed extract solution) as the major phenolic compound, together with vanillic acid, naringenin, and hydroxycinnamic acid. Total phenolic and flavonoid contents were 44.62 µg GAE/mg and 54.45 µg QE/mg extract, respectively. The extract showed moderate antioxidant activity, with DPPH and ABTS radical-scavenging activities of 9.35% and 30.88%, respectively, and FRAP and CUPRAC reducing capacities corresponding to absorbance values of 0.1235 at 700 nm and 0.2506 at 450 nm, respectively, at 0.2 mg/mL. In contrast, it exhibited potent inhibition of AChE (IC 50 = 6.13 ± 0.38 µg/mL), BChE (IC 50 = 6.42 ± 0.21 µg/mL), and AG (IC 50 = 4.05 ± 0.20 µg/mL). Molecular docking further showed that luteolin exhibited the strongest binding affinities toward AChE (− 10.657) and BChE (− 10.169), while showing moderate affinity for AG (− 7.242). These findings suggest that luteolin, as the predominant phenolic constituent, may contribute to the observed antioxidant and enzyme inhibitory activities of the extract; however, its specific contribution requires further experimental validation.