Chemical constituents isolated from stems of <i>Schisandra chinensis</i> and their antifeedant activity against <i>Tribolium castaneum</i>

One new sesquiterpene (α-iso-cubebenol acetate, <b>8</b>), together with 9 known compounds (1-7, 9, 10) were isolated from the stems of <i>Schisandra chinensis</i> (Turcz.) Baill. by repeated silica gel column chromatography. Based on the results of MS, NMR spectra and comparing with literature data, the six dibenzocyclooctadiene lignans were identified as schizandrin A to C (1-3), schizandrin (4), schisantherin A (5) and gomisin J (6), the two sesquiterpenes were identified as α-iso-cubebenol (7) and α-iso-cubebenol acetate (8), while the two triterpenic acids were identified as ganwuweizic acid (9) and kadsuric acid (10). The antifeedant activity of the 10 compounds against <i>Tribolium castaneum</i> adults was tested. Gomisin J (6) exhibited activity at 1500 ppm concentration with 40.3% antifeeding index percentages. As for the dibenzocyclooctene lignans (compounds <b>1–3</b>, <b>6</b>), the number of methylenedioxies and the position of hydroxyl groups were the main factors to affect their antifeedant activities.