Bicyclononane aldehydes and antiproliferative constituents from Amomum tsao-ko.

A racemic mixture of a new bicyclononane aldehyde, (1 RS,5 SR,6 RS)-5-hydroxybicyclo[4.3.0]non-2-ene-2-carbaldehyde (1) was isolated from the fruits of Amomum tsao-ko, together with 12 known compounds (2-13). The structure of 1 was determined on the basis of extensive spectroscopic analysis, including 1D and 2D NMR data. The antiproliferative activity of compounds 1-13 was assessed in the murine neuroblastoma cell line N2a.