New and bioactive sesquiterpenes from Schisandra sphenanthera

Three new sesquiterpenes, schisansphenins A (1) and B (2) and (-)-γ-cuparenol (3), were isolated from an acetone extract of the fruits of Schisandra sphenanthera. The known compound 4 was isolated for the frist time from a natural source. The structures of the isolated compounds were elucidated through extensive spectroscopic analyses, particularly 2D-NMR experiments ( 1H, 1H-COSY, HMQC, HMBC, and NOESY). A plausible biogenetic pathway for schisansphenin B (2) is proposed. Compounds 2 and 3 significantly reduced activation of NF-AT and NF-κB in the luciferase-reporter assay. Copyright © 2011 Verlag Helvetica Chimica Acta AG, Zürich, Switzerland.