This study presents a comprehensive evaluation of the phenolic composition and biological activities of methanolic extracts obtained from the aerial (GLM) and root (GLRM) parts of Glaucium leiocarpum. Phenolic profiling was conducted using reversed-phase high-performance liquid chromatography (RP-HPLC), revealing catechin hydrate, 3-hydroxybenzoic acid, syringic acid, hesperidin, chlorogenic acid, caffeic acid, and trans-cinnamic acid as major constituents in GLM.
In contrast, GLRM exhibited a more diverse phenolic profile, including epicatechin, benzoic acid, quercetin, gallic acid, and rosmarinic acid. Antioxidant activities were evaluated using DPPH and FRAP assays, with GLRM demonstrating stronger radical scavenging capacity (IC₅₀: 36.96 µg/mL) and higher ferric reducing power (173.20±0.68 mg TE/g extract).
GLRM also contained significantly higher levels of total phenolics (142.81±2.87 mg GAE/g) and flavonoids (76.67±0.72 mg QE/g). Antimicrobial assays demonstrated that only GLRM exerted inhibitory effects against Staphylococcus aureus (8.7±0.57 mm), Enterococcus faecalis (7.7±0.57 mm), and Streptococcus pneumoniae (15.0±0.0 mm).
Cytotoxicity studies, assessed by the XTT assay, revealed potent antiproliferative effects against HT-29 colorectal cancer cells (IC₅₀: 3.59 µg/mL for GLM, 2.29 µg/mL for GLRM) and moderate activity against A549 lung carcinoma cells (IC₅₀: 36.01 µg/mL for GLM, 21.99 µg/mL for GLRM). Furthermore, GLRM exhibited strong anticholinesterase activity, with IC₅₀ values of 2.85±0.27 µg/mL for acetylcholinesterase (AChE) and 2.47±0.07 µg/mL for butyrylcholinesterase (BChE).
Overall, these findings underscore G. leiocarpum, particularly its root extract, as a valuable source of bioactive secondary metabolites, owing to its rich polyphenolic profile and notable antioxidant, antimicrobial, cytotoxic, and cholinesterase inhibitory activities.