Neuroprotective and acetylcholinesterase inhibitory activities of alkaloids from Solanum lyratum Thunb.: An in vitro and in silico analyses

The n-BuOH extract from the herb of Solanum lyratum Thunb. (Solanaceae) was purified by various chromatographic methods, which led to the isolation of seven undescribed alkaloids ((−)-(7′S)–N-feruloyltyramine A, (+)-(7′R)-N-feruloyltyramine A, (+)-(7′S)–N-solanamide A, (−)-(7′R)-N-solanamide A, 7′S-perillascens, solanpyrrole A, and (Z)-asmurratetra A) and 13 known alkaloids, including four pairs of enantiomers. Extensive spectroscopic data and electronic circular dichroism (ECD) calculations were applied to determine the structures of the undescribed compounds. In in vitro biological activity assays, (−)-(7′S)–N-feruloyltyramine A and (+)-(7′R)-N-feruloyltyramine A exhibited pronounced neuroprotective effects against SH-SY5Y cell damage with survival rates of 75.98% and 76.61%, respectively, at 50 μM. Additionally, (−)-(7′S)–N-feruloyltyramine A and N-cis-feruloyl-3′-methoxy-tyramine displayed acetylcholinesterase (AChE) inhibitory effects with IC50 values of 7.41 ± 1.76 μM and 9.21 ± 0.89 μM, respectively. Molecular docking simulations revealed that (−)-(7′S)–N-feruloyltyramine A had a binding site for AChE. These findings reveal the structural diversity of the bioactive compounds in S. lyratum and provides insights into the use of this information for the production of functional components in the pharmaceutical industry.