Two new anthraquinones with antiviral activities from the barks of Morinda citrifolia (Noni)

Two new anthraquinones, 1,3-dihydroxy-5-methoxy-6-methoxymethyl-2-methyl-9,10-anthraquinone (1) and 1,3-dihydroxy-5-methoxy-2,6-bismethoxymethyl-9,10-anthraquinone (2), together with ten known anthraquinone derivatives (3-12), three coumarin derivatives (13-15), and 6-gingerol (16) were isolated from the barks of Morinda citrifolia (Noni) collected in the Yongxing island of Xisha. The structures of compounds (1-16) were determined on the basis of extensive spectroscopic analyses, as well as by comparison with literature reports. The new compounds 1 and 2 were tested for their antiviral, cytotoxic, and antibacterial activities. In the primary bioassays, compounds 1 and 2 displayed weak antiH1N1 activity with IC50 values of 66.1 and 10.5 mu M, respectively. In addition, compound 2 showed weak anti-H3N2 activity with IC50 value of 11.5 mu M, and had weak antimicrobial activity against Staphylococcus aureus with MIC value of 24.5 mu M. (C) 2015 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.