A new hTopo I isomerase inhibitor produced by a mangrove endophytic fungus no. 2240

Abstract

A new hTopo I isomerase inhibitor, (+)-3,3′,7,7′,8,8′-hexahydroxy-5,5′-dimethylbianthraquinone (2240A), was isolated from the mangrove endophytic fungus no. 2240 collected from an estuarine mangrove at the South China Sea coast. Its structure was elucidated by spectral analyses including two-dimensional NMR, HR-EI-MS, IR, and UV. The hTopo I isomerase inhibition experiment showed that 2240A (1) possessed strong inhibiting activity. When its inhibition concentration was 4.65 μmol/l, its percent inhibition rate was 59.1%, while the lowest inhibition concentration of the positive control camptothecin was 1.00 × 10³ μmol/l.

Keywords:

• mangrove endophytic fungus
• (+)-3,3′,7,7′,8,8′-hexahydroxy-5,5′-dimethylbianthraquinone
• 2240A
• hTopo I isomerase inhibitor

Acknowledgements

We wish to acknowledge the financial support from the National Natural Science Foundation of China (20072058, 20572136), the 863 Foundation of China (2003AA624010, 2006AA09Z422), the Natural Science Foundation of Guangdong Province, China (021732,2003A3050401), and the Star Lake Biotechnology Co. Inc., Zhaoqing, Guangdong, China.