ANTIMITOTIC AND CYTOTOXIC FLAVONOLS FROM ZIERIDIUM-PSEUDOBTUSIFOLIUM AND ACRONYCHIA-PORTERI

Bioassay-guided fractionation of the extracts of Zieridium pseudobtusi folium and Acronychia porteri led to the isolation of 5,3'-dihydroxy-3 ,6,7,8,4'-pentamethoxyflavone [1], which showed activity against (KB) human nasopharyngeal carcinoma cells (IC50 0.04 mu g/ml) and inhibited tubulin assembly into microtubules (IC50 12 mu M). Two other known fl avonols, digicitrin [2] and 5-hydroxy-3,6,7,8,3',4'-hexamethoxyflavone [5], were also isolated together with three new ones, 3-O-demethyldig icitrin [3], 3,5,3'-trihydroxy-6,7,8,4'-tetramethoxyflavone [4], and 3 ,5-dihydroxy-6,7,8,3',4'-pentamethoxyflavone [6]. All of these flavono ls showed cytotoxic activity against KB cells.