Abstract:
Cangumycins A-F (
1-6 ), six new angucyclinone analogues, together with two known ones (
7 and
8 ), were isolated from the fermentation broth of a soil-derived
Streptomyces sp. KIB-M10. Structures of these compounds were elucidated
via a joint use of spectroscopic analyses and single-crystal X-ray diffractions. Among them, cangumycins E (
5 ) and F (
6 ) share a C-ring cleaved backbone, and cangumycins B (
2 ) and E (
5 ) exhibit potent immunosuppressive activity (IC
50 8.1 and 2.7 μmol·L
-1, respectively) against human T cell proliferation at a non-cytotoxic concentration.