Antiproliferative Trihydroxyalkylcyclohexenones from Pleiogynium timoriense

[Image: see text] Investigation of a DCM extract of the bark of Pleiogynium timoriense from the former Merck collection of natural product extracts for antiproliferative activity indicated that it was active with an IC(50) value of 1.3 μg/mL against the A2780 ovarian cancer cell line. Bioassay-directed fractionation of this extract yielded the three new bioactive trihydroxyalkylcyclohexenones 1–3. Their structures were determined by a combination of spectroscopic and chemical methods. Compounds 1–3 exhibited submicromolar antiproliferative activity against the A2780 human ovarian cancer cell line, with IC(50) values of 0.8, 0.7, and 0.8 μM, respectively.