New Anthraquinone and Iridoid from the Fruits of Morinda citrifolia
Chemical and pharmaceutical bulletin
Morinda citrifolia L. (Rubiaceae), known as "noni", is a small tree that grows widely across Polynesia. The roots, barks, stems, leaves and fruits have been used traditionally as a folk medicine for the treatment of many diseases 1) including diabetes, hypertension 2) and cancer. 3) Furthermore, today "noni juice", which is made from the fruits of this plant, is widely drunk for the purported prevention of lifestyle-related diseases such as diabetes, hypertension, cardiopathy and cerebral
... and cerebral apoplexy caused by arteriosclerosis. In our previous study of the bioactive constituents of M. citrifolia fruits for the prevention of arteriosclerosis, six lignans were isolated as active components. 4) The rubiaceous plant is well-known for its anthraquinone and iridoid constituents. In earlier studies of anthraquinones from M. citrifolia, morenone-1, morenone-2, nordamnacanthal, morindone, rubiadin, rubiadin-1-methyl ether and 7-hydroxy-8-methoxy-2-methylanthraquinone were identified in the root. 5-7) Additionally, morindone, physcion and physcion-8-O-a-L-arabinopyranosyl(1-3)-[b -D-galactopyranosyl(1-6)]-b -D-galactopyranoside were found in its heartwood, 8) while 6,8-dimethoxy-3methylanthraquinone 1-O-b-rhamnopyranosyl(1-4) b-Dglucopyranoside has been isolated from the flower. 9) In studies of iridoids from M. citrifolia, asperuloside, 10) asperulosidic acid, 11) 6a-hydroxyadoxoside, 12) 6b,7b-epoxy-8-episplendoside, 12) borreriagenin, 12) citrifolinin B, 12) deacetylasperuloside 12) and dehydromethoxygaertneroside 12) were all isolated from the fruits, while citrifolinin A and citrifolinoside were isolated from the leaves. 13, 14) The present paper describes the isolation and characterization of one new anthraquinone, 5,15-dimethylmorindol (1), together with five known anthraquinones, alizarin-1-methylether (2), 15) anthragallol-1,3-dimethylether (3), 16) anthragallol-2-methylether (4), 17) 6-hydroxy-anthragallol-1,3-dimethylether (5) 18) and morindone-5-methylether (6), 19) and one new iridoid, morindacin (7), together with two known iridoids, asuperlosidic acid (8) 20) and deacetylasperulosidic acid (9). 20) Compound 1 was obtained as a yellow amorphous powder. The molecular formula of 1 was determined by HR-EI-MS to December 2005 Notes Chem. Pharm. Bull. 53(12) 1597-1599 (2005) 1597 From the fruits of Morinda citrifolia L., one new anthraquinone, 5,15-O-dimethylmorindol, together with five known anthraquinones and one new iridoid, morindacin, together with two known iridoids, were isolated. Their structures were elucidated by analysis of spectroscopic data.