Cladosporinone, a new viriditoxin derivative from
the hypersaline lake derived fungus Cladosporium
cladosporioides
A new cytotoxic viriditoxin derivative, cladosporinone (1), along with the known viriditoxin (2) and two viriditoxin derivatives
(3 and 4) were obtained from the fungus Cladosporium cladosporioides isolated from the sediment of a hypersaline lake in
Egypt. The structure of the new compound (1) was determined by 1D and 2D NMR measurements as well as by high-resolution
ESIMS and electronic circular dichroism spectroscopy. All isolated compounds were studied for their cytotoxicity against the
murine lymphoma cell line L5187Y and for their antibiotic activity against several pathogenic bacteria. Viriditoxin (2) was the
most active compound in both bioassays. Compound 1 also exhibited strong cytotoxicity against the murine lymphoma cell line
L5187Y with an IC50 value of 0.88 μM, whereas its antibiotic activity was weak