Chemistry Reference
In-Depth Information
14
15
NH group within the core of this ring (13). Their antimicrobial spectrum is
mainly against gram-positive bacteria. Among these compounds, the rifamycins,
produced by
Amycolatopsis mediterranei
, can be cited as effective drugs in
the treatment of tuberculosis and leprosy because of their antimicrobial effect
against
Mycobacterium tuberculosis
. The biological activity of rifamycins is
due to their ability to inhibit DNA-dependent RNA synthesis. They are also
used to treat infections by
Listeria
species,
Neisseria gonorrhoeae, Haemophilus
influenza
,and
Legionella pneumophila
. Rifamycins that are currently available
include rifampicin (
15
), rifabutin (
16
), rifapentine (
17
), and rifaximin (
18
).
Streptogramins are compounds produced by some streptomycetes and can
adopt one of two different chemical structures (A and B). Type A are cyclic
hybrid peptide-polyketide macrolactones, whereas type B are cyclic hexa- or
hepta-depsipeptides, cyclized via an ester bond between the C-terminal carboxyl
group and the secondary group of a threonine residue at position 2. They have
a remarkable mode of action because of the ability of the A and B types to act
16
