New Thymoquinol Glycosides and Neuroprotective Dibenzocyclooctane Lignans from the Rattan Stems of Schisandra chinensis

Three new Lignans (1 - 3), together with four new thymoquinol glycosides (4 - 7), were isolated from 70%-EtOH extract of the rattan stems of Schisandra chinensis. The structures of 1 - 7 were elucidated by detailed spectroscopic analyses, and these new compounds were identified as pinobatol-9-O-β-d-glucopyranoside (1), 1,2,13,14-tetramethoxydibenzocyclooctadiene 3,12-O-β-d-diglucopyranoside (2), 3,7-dihydroxy-1,2,13,14-tetramethoxydibenzocyclooctadiene 12-O-β-d-glucopyranoside (3), thymoquinol 2-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside (4), thymoquinol 2-O-α-d-arabinofuranosyl-(1→6)-β-d-glucopyranoside (5), thymoquinol 5-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside (6), and thymoquinol 5-O-α-d-arabinofuranosyl-(1→6)-β-d-glucopyranoside (7). The neuroprotective activity of 1 - 7 was evaluated on PC12 cells with neurotoxicity induced by amyloid-beta 1 - 42 (Aβ_{1 - 42} ). Compounds 2 and 3 showed protecting activity against Aβ-induced toxicity in PC12 cells.