New cytotoxic cyclobutanoid amides, a new furanoid lignan and anti-platelet aggregation constituents from Piper arborescens

Three new cyclobutanoid amides with trans-trans-trans configurations, piperarborenine C, piperarborenine D and piperarborenine E, and a new furanoid lignan, (+)-arborone, together with twelve known compounds, were isolated from the stems of Piper arborescens. The structures of these new compounds were determined by means of spectral analyses. Piperarborenine C, (+)-diayangambin, piplartine, piperolactam B, piperolactam C, aristolactarn Bill, goniothalactam, and methyl trans-3,4,5-trimethoxycinnamate possessed anti-platelet aggregation activity in vitro. Among them, piplartine showed the most potent anti-platelet aggregation activity induced by Collagen and showed an IC50 value of 21.5 mu M. Piperarborenines A-E, piperarborenine, aristololactam BIII and goniothalactam showed significant cytotoxic activity (IC50 values < 4 mu g/mL) against P-388, HT-29 and A549 cell lines in vitro.