Bioactive Phenolics of Lygeum spartum L.: Insights Into Antioxidant, Anticholinesterase, and Antityrosinase Activities

Abstract

The phenolic composition of roots and leaves of Lygeum spartum L., a Mediterranean Poaceae species, was analyzed by HPLC–DAD, revealing an organ‐specific distribution of phenolic compounds, with ferulic acid identified as the predominant phenolic compound in the methanolic leaf extract (4.07 mg/g) and higher levels of flavonoids and phenolic acids in leaves than in roots. Antioxidant activity was evaluated using DPPH, ABTS+, and CUPRAC assays, while enzyme inhibitory activity was assessed against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and tyrosinase using L‐DOPA as the substrate. Methanolic extracts, particularly those from leaves, exhibited the highest antioxidant activity among the tested extracts (IC50 = 281.48 µg/mL for DPPH; 105.72 µg/mL for ABTS+; A0.5 = 182.36 µg/mL for CUPRAC), whereas petroleum ether extracts were largely inactive. Enzyme inhibitory activity was generally weak, with all extracts exhibiting little or no inhibition of AChE and BChE, while the methanolic leaf extract showed weak tyrosinase inhibitory activity (IC50 = 310.69 µg/mL). To the best of our knowledge, this is the first study reporting the cholinesterase and tyrosinase inhibitory activities of L. spartum L. These results indicate that L. spartum is a source of phenolic compounds exhibiting moderate antioxidant activity, whereas its enzyme inhibitory effects are limited.