Naphthohydroquinones, naphthoquinones, anthraquinones, and a naphthohydroquinone dimer isolated from the aerial parts of Morinda parvifolia and their cytotoxic effects through up-regulation of p53

Five unknown compounds, morindaparvins C-G, consisting of naphthohydroquinones, a naphthoquinone, an anthraquinone, and a naphthohydroquinone dimer, together with three known quinones and seven other known compounds, were isolated from the aerial parts of Morinda parvifolia. The structures of morindaparvins C, D, E, F, and G were elucidated on the basis of spectroscopic or X-ray diffraction analysis as methyl 4-hydroxy-1,6-dimethoxy-naphthalene-2-carboxylate, methyl 4,8-dihydroxy-1-methoxy-naphthalene-2-carboxylate, 3-amino-6-methoxy-2-methoxycarbonyl-1,4-naphthoquinone, 1,4-dihydroxy-7-hydroxymethyl-anthraquinone, and dimethyl 1,1'-dihydroxy-4,4',7,7'-tetramethoxy-2,2'-binaphthalene-3,3'-dicarboxylate, respectively. Naphthoquinones and naphthohydroquinone dimers were previously unknown in the genus Morinda. In addition, the compounds were tested for cytotoxicity against four human cancer cell lines HeLa, A2780, Ketr3 and MCF-7 and their effects on p53-activated transcription. Three naphthoquinones had moderate cytotoxic effects with IC50 values ranging from 1.51 to 9.56 μM, through up-regulation of p53 transcriptional activity.