Acetogenins from the Stem of and Their Cytotoxic Activity.

Four new adjacent bis-tetrahydrofuran acetogenins, bullacin C (), uvarirufin (), and uvariasolins III () and IV (), along with 11 known acetogenins, were isolated from the stem of . Their structures were elucidated based on spectroscopic data analysis, including 1D and 2D NMR, HRESIMS, and MALDI-MS/MS of the lithium adducts. Absolute configurations were assigned using Mosher ester analysis and ECD measurements. Uvarirufin () possesses a unique C-39 skeleton among acetogenins. Most tested acetogenins exhibited cytotoxicity against human cancer cell lines (HCT 116, 22Rv1, MDA-MB-435, OVCAR3). Squamocin () and uvarirufin () were found to be the most potent, with an IC value of 1.2 μM for both in HCT 116 colon cancer cells. Additionally, a new application of Dragendorff's reagent is proposed herein for the TLC detection of acetogenins.