Rifamycin S: A "Classic" Rifamycin with Potent Antimicrobial Activity but Poor Tolerability
Rifamycin S belongs to the family of ansamycin antibiotics, rifamycins. Initially, rifamycins were discovered referred to as rifamycin A, B, C, D, E in 1957. Among these, rifamycin B isolated in a pure form. Although its antimicrobial activity was moderate, it was oxidized and hydrolyzed to yield the highly active rifamycin S, a quinone molecular with potent antimicrobial activity but poor tolerability. Rifamycins inhibit DNA-dependent RNA polymerase in susceptible strains of bacteria, including
Mycobacterium tuberculosis and Gram-positive bacteria. The rifamycin group includes the "classic" rifamycins as well as active rifamycin derivatives, rifampicin [
R0079], rifaximin [
R0101] and rifabutin [
R0211]. (The product is for research purpose only.)