Two azafluoranthene alkaloids and a phytoecdysone from the stems of Cyclea barbata.

Two new azafluoranthene alkaloids (1 and 2), and a new phytoecdysone (3), were isolated from the stems of Cyclea barbata Miers, together with six known compounds (4-9). Their structures were elucidated by spectroscopic data analysis and comparison with published data. This is the first report of azafluoranthene alkaloids (1 and 2) and phytoecdysones (3, 8, and 9) from Cyclea genus. In in vitro bioassay, four isolates (3, 5, 6, and 9) showed moderate hepatoprotective activity against N-acetyl-p-aminophenol (APAP)-induced toxicity in HepG2 cells.