Inhibitory effects of compounds from ice plant (Mesembryanthemum crystallinum L.) against tyrosinase and soluble epoxide hydrolase: In vitro and in silico studies

This study aims to investigate the isolation and structural elucidation of 17 known compounds, including three amides (1–3), two flavonoids (4–5), and 12 phenolic compounds (6–17) via a phytochemical investigation of Mesembryanthemum crystallinum L. (ice plant) through a combination of spectroscopic techniques. Among them, trans-N-coumaroyltyramine (1) exhibited strong tyrosinase inhibition with an IC₅₀ value of 12.41 ± 0.88 µM, while trans-N-feruloyloctopamine (3) showed potent inhibition of soluble epoxide hydrolase (sEH) with an IC₅₀ value of 18.51 ± 0.81 µM. Enzyme kinetics analysis revealed that active compounds 1 and 3 acted as non-competitive inhibitors of tyrosinase and sEH, respectively. Additionally, molecular docking simulations were performed to reveal binding interactions within the enzyme allosteric sites. Molecular dynamics simulations further confirmed the stability of the protein-ligand complexes, reinforcing the observed inhibition modes. These findings highlight the therapeutic potential of secondary metabolites from M. crystallinum as promising candidates for discovering and developing natural tyrosinase and sEH inhibitors.