Bioactivity profiling of Lamium album by HPTLC combined with effect-directed analysis and high-resolution tandem mass...

Lamium album (white dead nettle), a traditional medicinal plant from the Lamiaceae family, is known for its anti-inflammatory, antioxidant, and antimicrobial properties, yet its bioactive profile remains insufficiently characterized. This study aimed to evaluate the antioxidant, enzyme inhibitory, and antibacterial activities of ethanolic extracts from the aerial parts and flowers of L. album, with focus on tentatively identifying active constituents through on-plate effect-directed assays analyses and high-resolution tandem mass spectrometry (HR-MS/MS). High-performance thin-layer chromatography (HPTLC) was used to obtain phytochemical profiles and for bioactivity screening. The HPTLC plates were derivatized with AlCl₃, anisaldehyde, and 2-aminoethyl diphenylborinate (NP)/ polyethylene glycol (PEG) reagents to enhance compound visualization and aid in preliminary phytochemical classification. Antioxidant activity was tested using ABTS•⁺ and DPPH• radical scavenging assays, while enzyme inhibition was evaluated for α-amylase, α-glucosidase, lipase, and acetylcholinesterase, relevant enzymes to metabolic and neurodegenerative disorders. Antibacterial activity was tested against Bacillus subtilis. Both plant parts showed multiple zones of activity across all assays, with the aerial parts generally showing stronger responses. Some of the inhibitory zones were further analyzed using HR-MS/MS leading to tentative identification of several active compounds, including linoleic acid, linolenic acid, hydroxylated fatty acids, tiliroside, and tricoumaroyl spermidine-the latter reported for the first time in L. album. These findings demonstrate that L. album harbors a diverse array of bioactive constituents with potential applications in the management of metabolic dysfunctions, neurodegeneration, and bacterial infections. The integration of HPTLC-effect-directed assays and HPTLC-HR-MS/MS analysis proves to be an effective approach for rapid screening and tentative identification of natural product-derived therapeutics.