PUB - Publikationen an der Universität Bielefeld

Three new anthraquinone derivatives including (2S, 3R)-1,2,3,4-tetrahydro-2,3,6-trihydroxy-2-methylan-thracene-9,10-dione (1), 3,6-dihydroxy-1,2-dimethoxyanthraquinone (2) and 1,6-dihydroxy-2-hydroxymethyl5-methoxyanthraquinone (3) together with thirteen known compounds including eleven anthraquinones and two triterpenes were isolated from the methanolic crude extract of the stem barks of Morinda lucida. The structures of the new compounds were unambiguously elucidated on the basis of modern NMR spectroscopic methods, as well as by high-resolution mass spectrometry. The known compounds were identified on the basis of their spectral characteristics and by comparison with literature data. The antimicrobial activities of (2S, 3R)1,2,3,4-tetrahydro-2,3,6-trihydroxy-2-methylanthracene-9,10-dione (1), the methanolic crude extract and its fractions were evaluated against five bacteria and four fungi. The lowest values of the MIC (256 mu g/mL) were recorded on Candida parapsilosis, Cryptococcus neoformans for the methanolic crude extract and on Salmonella typhi for the ethyl acetate fraction.