Exploring the Phytochemical Profile and Biological Activities, Supported by Molecular Docking and Dynamics Simulation...

The current research was conducted to explore for the first time the phytochemical composition, of the methanolic extract and the fractions of Lysimachia tyrrhenia U.Manns & Anderb. using a developed LC-ESI-MS/MS method. In addition, antioxidant, cholinesterase inhibitory, and photoprotective activities were evaluated to highlight the potential therapeutic relevance of this species. In vitro trials were undertaken to investigate the antioxidant activity of the L. tyrrhenia sampls based on 2-diphenyl-1-picrylhydrazyl (DPPH^•), 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS^•+), cupric reducing antioxidant capacity (CUPRAC), ferric ions (Fe³⁺) reducing assay (FRAP) and phenanthroline. The photoprotective potential of the L. tyrrhenia extracts against UV-induced damage was assessed through in vitro sun protection factor (SPF) measurements, while the neuroprotective effect was examined in vitro against acetylcholinesterase (AChE) enzyme. This study accurately estimated the chemical bonding between the identified molecules derived from LC-MS/MS and the AChE. The LC-MS/MS results revealed that rutin, epicatechin, hesperidin, are the abundant compounds in most of the samples. All studied samples demonstrated remarkable antioxidant potentials, among them the fraction I was the strongest, with IC₅₀ values of 11.71 ± 0.17 µg/mL (DPPH), 1.82 ± 0.05 µg/mL (ABTS), 4.69 ± 0.15 µg/mL (CUPRAC), and 1.00 ± 0.07 µg/mL (phenanthroline). It also exerted the considerable AChE inhibitory effect (IC₅₀ = 58.31 ± 0.18 µg/mL). Molecular docking studies have highlighted hesperidin as a promising AChE inhibitor, with a binding energy of -10.5 kcal/mol. Molecular dynamic simulations further support hesperidin's potential, showing stable interactions with AChE. Moreover, all fractions showed high photoprotective activity with the SPF value ranged from 34.58 to 35.19. These results highlight the therapeutic potential of L. tyrrhenia as a source of bioactive compounds for developing new approaches for managing cholinesterase-related disorders and oxidative stress.