Inhibition of the G2 DNA damage checkpoint by oliveroline isolated from Duguetia odorata.

Plant extracts obtained from the U.S. National Cancer Institute's Open Repository collection have been screened for their ability to inhibit the G2 DNA damage checkpoint. An extract of Duguetia odorata showed promising activity in the assay. Bioassay-guided fractionation revealed that oliveroline (1) was responsible for the G2 checkpoint inhibitory activity of the D. odorata extract. The new alkaloid N-methylguatterine (2) was identified during this investigation.