New prenylated anthraquinones and xanthones from Vismia guineensis

From the roots of Vismia guineensis 23 structurally related compounds were isolated and identified. Ten of them are new constituents, namely 3-O-(2-hy droxy-3-methylbut-3-enyl)-emodin (1); 3-O-(2-methoxy-3-methylbut-3-enyl)-em odin (2); 1,8-dihydroxy-3-(2-methoxy-3-methylbut-3-enyloxy)-6-methylxanthon e (3); 1,8-dihydroxy-3-geranyloxy-6-methylxanthone (4); 1,8-dihydroxy-3-iso prenyloxy-6-methylxanthone (5); 1,8-dihydroxy-3-(3,7-dimethyl-7-methoxyoct- 2-enyloxy)-6-methylxanthone (6); 3-O-(E-3-hydroxymethylbut-2-enyl)-emodin ( 7); 3-O-(3-hydroxymethyl-4-hydroxybut-2-enyl)-emodine (8); 1,8-dihydroxy-3- (E-3-hydroxymethylbut-2-enyloxy)-6-methylxanthone (9); and 1,8 -dihydroxy-3 -(3-hydroxymethyl-4-hydroxybut-2-enyloxy)-6-methylxanthone (10). Their stru ctures were established by means of EIMS and a combination of homonuclear a nd heteronuclear 2D NMR techniques. Furthermore, an in vitro preliminary sc reening of antimitotic activity of all the isolated compounds was also eval uated.