Thiopeptide compounds
View Patent ↗A microorganism belonging to the genus Bacillus is cultured and thiopeptide compounds QN3323 and thiocillin I/II compounds are collected from the culture medium. The compounds are useful as drugs to treat infections caused by multidrug-resistant bacteria.
1. Thiopeptide compounds of the following formula or their pharmaceutically acceptable salts:
wherein A represents CH—OH or C═O; R represents H or CH 3 ;
R a and R b each represent H or CH 3 ;
provided that when R a is H, then R b is CH 3 ; when R a is CH 3 , then R b is H; when A is CH—OH, then R a is H and R b is CH 3 .
2. Compounds or their pharmaceutically acceptable salts as claimed in claim 1 , wherein A is C═O, R is H, R a is CH 3 , and R b is H.
3. Compounds or their pharmaceutically acceptable salts as claimed in claim 1 , wherein A is C═O, R is CH 3 , R a is CH 3 , and R b is H.
4. Compounds or their pharmaceutically acceptable salts as claimed in claim 1 , wherein A is CR—OH, R is H, R a is H, and R b is CH 3 .
5. A pharmaceutical composition that comprises, as the active ingredient thereof, a compound of claim 1 or its pharmaceutically acceptable salt and a pharmaceutically acceptable carrier.
6. The pharmaceutical composition as claimed in claim 5 , which is an antibacterial agent.
7. A method for producing thiopeptide compounds of formula (I′), which comprises cultivating cells of Bacillus sp. QN03323 (FERM BP-7864) followed by collecting the thiopeptide compounds of claim 1 from the resulting culture.
8. A method for treating infections caused by multidrug-resistant bacteria, which comprises administering to a patient in need thereof an effective amount of a thiopeptide compound of the following formula I′ or a pharmaceutically acceptable salt thereof:
wherein A represents CH—OH or C═O; R represents H or CH 3 ;
R a and R b each represent H or CH 3 ;
provided that when R a is H, then R b is CH 3 , when R a is CH 3 , then R b is H; when A is CH—OH, then R a is H and R b is CH 3 .
9. The method as claimed in claim 8 , which is for treating infections caused by methicillin-resistant Staphylococcus aureus or vancomycin-resistant Enterococcus.