What is the structure of quinolone?
Quinolones are potent antimicrobial agents with a basic chemical structure of bicyclic ring. Fluorine atom at position C-6 and various substitutions on the basic quinolone structure yielded fluoroquinolones, namely norfloxacin, ciprofloxacin, levofloxacin, moxifloxacin and numerous other agents.
What is the mechanism of action for quinolones?
Mechanism of action Quinolones inhibit replication of bacterial DNA by blocking the ligase domain of bacterial DNA gyrase (topoisomerase II); some also inhibit topoisomerase IV. These enzymes relax DNA supercoils and enable DNA replication and repair (see Fig. 51.1). The effect of quinolones is bactericidal.
What bacterial structure does fluoroquinolones target?
The quinolones are a potent group of drugs that target the essential bacterial enzymes DNA gyrase and topoisomerase IV. DNA gyrase is the primary target of Gram negative organisms however, it is topoisomerase IV that is the primary target of Gram positive organisms.
Are fluoroquinolones chemotherapy?
Fluoroquinolones are a potent form of chemotherapy.
What is the essential pharmacophore required for quinolones?
The basic pharmacophore, or active structure, of the fluoroquinolone class is based upon the quinoline ring system. The addition of the fluorine atom at C6 distinguishes the successive-generation fluoroquinolones from the first-generation of quinolones.
What step of replication is inhibited by the quinolone group of antibiotics?
Quinolones inhibit enzyme function by blocking the resealing of the DNA double-strand break, but, in addition, this process stabilizes a catalytic intermediate covalent complex of enzyme and DNA that serves as a barrier to movement of the DNA replication fork (Wentzell and Maxwell 2000) or transcription complexes ( …
Can I take Cipro while on chemo?
The fluoroquinolones also have excellent oral bioavailability and are well tolerated by most patients. Ciprofloxacin was the first fluoroquinolone studied for chemotherapy-induced neutropenia.
What do quinolones cover?
Fluoroquinolones are active against a wide range of aerobic gram-positive and gram-negative organisms. Gram-positive coverage includes penicillinase- and non-penicillinase producing Staphylococci, Streptococcus pneumoniae and viridans, Enterococcus faecalis, Listeria monocytogenes, and Nocardia species.
How are fluoroquinolones classified according to their chemical structure?
Fluoroquinolones can be classified (Table 1) [4] according to their chemical structure but the most commonly used and clinically useful classification is based on the spectrum of activity. The initial quinolone compounds had a limited spectrum of activity against gram negative organisms thus, restricting their clinical use.
How does fluorouracil affect the formation of RNA?
There is evidence that the metabolism of fluorouracil in the anabolic pathway blocks the methylation reaction of deoxyuridylic acid to thymidylic acid. In this manner fluorouracil interferes with the synthesis of deoxyribonucleic acid (DNA) and to a lesser extent inhibits the formation of ribonucleic acid (RNA).
What is the structure of the quinolone nucleus?
The main quinolone nucleus is a nitrogen-containing, 8-membered heterocyclic aromatic quinoline ring. In studying the structure-activity relationships of the early 4-quinolones, the 3-carboxyl group and 4-oxo groups were linked to antimicrobial activity.
What is the role of fluorouracil in the environment?
It has a role as a xenobiotic, an environmental contaminant, a radiosensitizing agent, an antineoplastic agent, an immunosuppressive agent and an antimetabolite. It is a nucleobase analogue and an organofluorine compound. It derives from a uracil.