posted on 2013-11-08, 00:00authored byHahk-Soo Kang, Bernard D. Santarsiero, Hyunjung Kim, Aleksej Krunic, Qi Shen, Steven M. Swanson, Hee-Byung Chai, A. Douglas Kinghorn, Jimmy Orjala
The cell extract of a cultured terrestrial Nostoc sp. (UIC 10062), obtained from a sample collected at Grand Mere State park in Michigan, displayed antiproliferative activity against the HT-29 human colon cancer cell line. Bioactivity-guided fractionation of the cell extract, combined with LC-MS analysis, led to the isolation of two new cyclophanes, named merocyclophanes A and B (1 and 2). The planar structures were determined by various spectroscopic techniques including HRESIMS, and 1D and 2D NMR experiments. The stereoconfiguration was assigned on the basis of X-ray crystallographic and CD analyses. The structures of merocyclophanes A and B (1 and 2) revealed a new natural [7.7]paracyclophane skeleton characterized by α-branched methyls at C-1/14. Merocyclophanes A and B (1 and 2) displayed antiproliferative activity against the HT-29 human colon cancer cell line with IC50 values of 3.3 and 1.7 μM, respectively.
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Publisher Statement
NOTICE: this is the author’s version of a work that was accepted for publication in Phytochemistry . Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Phytochemistry , [Vol 79, 2012] DOI: 10.1016/j.phytochem.2012.03.005