Mono-, Bi-, and triphenanthrenes from the tubers of Cremastra appendiculata.

Six newphenanthrene derivatives, including three monophenanthrenes (1-3), two biphenanthrenes (4 and 5), and a triphenanthrene (6), have been isolated from an ethanolic extract of the tubers of Cremastra appendiculata. Using spectroscopic methods, the structures of compounds 1-6 were determined as 1-hydroxy-4,7-dimethoxy-1-(2-oxopropyl)-1H-phenanthren-2-one (1), 1,7-dihydroxy-4-methoxy-1-(2-oxopropyl)-1H-phenanthren-2-one (2), 2-hydroxy-4,7-dimethoxyphenanthrene (3), 2,7,2'-trihydroxy-4,4',7'-trimethoxy-1,1'-biphenanthrene (4), 2,2'-dihydroxy-4,7,4',7'-tetramethoxy-1,1'-biphenanthrene (5), and 2,7,2',7',2' '-pentahydroxy-4,4',4' ',7' '-tetramethoxy-1,8,1',1' '-triphenanthrene (6), respectively. Compounds 1-6 and two known compounds, cirrhopetalanthin (7) and flavanthrinin (8), obtained previously from this plant, were evaluated against six human cancer cells and a normal cell line.