New neolignans from Selaginella picta and their protective effect on HT-22 cells.

Three new compounds, pictalignans A (1), B (2), C (3), along with three known analogues, syringaresinol (4), 3,3',5-trimethoxy-4',7-epoxy-8,5'-neoligan-4',9,9'-triol (5), 4,9-dihydroxy-4',7-epoxy-8',9'-dinor-8,5'-neolignan-7'-oic acid (6) were isolated from the 75% aqueous ethanol extract of Selaginella picta. Their structures were established by physicochemical properties and spectroscopic methods, and absolute configurations of new compounds were elucidated by experimental and calculated ECD spectra. Compounds 1-3 are neolignans with additional one or two C ₆ -C ₃ structural units attached to hydroxypropyl group, which are extremely rare in nature. All new compounds exhibited moderate protective effect against the injury of HT-22 cells induced by L-Glutamate in vitro, and compound 1 showed better protective effect than positive drug with the concentrations of 10 μM to 15 μM.
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