Morindaquinone, a new bianthraquinone from Morinda coreia roots
Phytochemical investigation of the roots of Morinda coreia led to the isolation of one new bianthraquinone, morindaquinone (1), together with 12 known compounds, soranjidiol (2), rubiadin-1-methyl ether (3), 2-methoxy-1,3,6-trihydroxyanthraquinone (4), 1-hydroxy-2-methylanthraquinone (5), tectoquinone (6), nordamnacanthal (7), damnacanthal (8), 2-formylanthraquinone (9), 3-hydroxy-2-hydroxymethylanthraquinone (10), lucidin-ω-methyl ether (11), scopoletin (12) and (+)-mellein (13). The structures of these compounds were determined on the basis of extensive spectroscopic analyses, as well as by comparison with literature reports. Compound 1 was the first example of bianthraquinone found in the genus Morinda, whereas compound 13 was firstly isolated from this genus. Among them, compounds 2, 7, 8 and 10 exhibited moderate to weak cytotoxicity against human cervical (HeLa), human colon (HT 29) and human breast (MCF-7) cell lines, while compounds 6 and 9 – 11 showed weak anti-acetylcholinesterase activity.