Anthraquinones from Neonauclea calycina and their inhibitory activity against DNA topoisomerase II.

Tosa H, Iinuma M, Asai F, Tanaka T, Nozaki H, Ikeda S, Tsutsui K, Tsutsui K, Yamada M, Fujimori S.

In a series of searches for DNA topoisomerase II inhibitors from naturally occurring compounds, a wood extract of Neonauclea calycina MERR. (Rubiaceae) showed a moderate effect in vitro. Purification of the extract resulted in the isolation of seven known anthraquinones. The structures were characterized as damnacanthal, rubiadin 1-methyl ether, nordamnacanthal, morindone, damnacanthol, lucidin 3-O-primeveroside and morindone 6-O-primeveroside by spectral analysis, respectively. Damnacanthal and morindone showed an intensive inhibitory effect against topoisomerase II (IC50: 20 micrograms/ml and 21 micrograms/ml).

Biol Pharm Bull

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641

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