Anthraquinones with quinone reductase-inducing activity and benzophenones from Morinda citrifolia (noni) roots.

Two new benzophenones, morintrifolins A ( 1) and B ( 2), together with 14 known anthraquinones and four other known compounds, were isolated from a chloroform-soluble extract of Morinda citrifolia roots. Of the isolated compounds, four known anthraquinones, namely, 1,2-dihydroxyanthraquinone ( 3), 1,3-dihydroxy-2-methylanthraquinone ( 4), 2-hydroxy-3-(hydroxymethyl)anthraquinone ( 5), and 1,3,6-trihydroxy-2-methylanthraquinone ( 6), exhibited quinone reductase (QR)- inducing activity in Hepa lclc7 cells, with concentrations required to double QR activity of 12.0, 8.1, 0.94, and 0.56 microM, respectively.