Mangromicins A and B: structure and antitrypanosomal activity of two new cyclopentadecane compounds from Lechevalieria aerocolonigenes K10-0216

Two new cyclopentadecane antibiotics, named mangromicins A and B, were separated out from the culture broth of Lechevalieria aerocolonigenes K10-0216 by Diaion HP-20, silica gel and ODS column chromatography, and were finally purified by HPLC. The chemical structures of the two novel compounds were elucidated by instrumental analyses, including various NMR, MS and X-ray crystallography. Mangromicins A and B consist of cyclopentadecane skeletons with a tetrahydrofuran unit and a 5,6-dihydro-4-hydroxy-2-pyrone moiety. Mangromicins A and B showed in vitro antitrypanosomal activity with IC 50 values of 2.4 and 43.4 μg ml −1 , respectively. The IC 50 values of both compounds were lower than those of cytotoxicity against MRC-5 human fetal lung fibroblast cells.