Polyene antimycotic
Encyclopedia
Polyene antimycotics, sometimes referred to as polyene antibiotics, are a class of antimicrobial
polyene
compounds
that target fungi. These polyene antimycotics are typically obtained from some species of Streptomyces
bacteria. The polyenes bind to ergosterol
in the fungal cell membrane and promote leakiness which may contribute to fungal cell death. Amphotericin B
, nystatin
, and natamycin
are examples of polyene antimycotics.
s feature a large ring of atoms (essentially a cyclic ester
ring) containing multiple conjugated carbon-carbon double bond
s (hence polyene
) on one side of the ring and multiple hydroxyl
groups bonded to the other side of the ring. Their structures also often have a d-mycosamine (a type of amino-glycoside) group bonded to the molecule. The series of conjugated double bonds typically absorbs strongly in the ultraviolet-visible region of the electromagnetic spectrum
, often resulting in the polyene antibiotics having a yellow color.
Antimicrobial
An anti-microbial is a substance that kills or inhibits the growth of microorganisms such as bacteria, fungi, or protozoans. Antimicrobial drugs either kill microbes or prevent the growth of microbes...
polyene
Polyene
Polyenes are poly-unsaturated organic compounds that contain one or more sequences of alternating double and single carbon-carbon bonds. These double carbon-carbon bonds interact in a process known as conjugation, which results in an overall lower energy state of the molecule.Organic compounds with...
compounds
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
that target fungi. These polyene antimycotics are typically obtained from some species of Streptomyces
Streptomyces
Streptomyces is the largest genus of Actinobacteria and the type genus of the family Streptomycetaceae. Over 500 species of Streptomyces bacteria have been described. As with the other Actinobacteria, streptomycetes are gram-positive, and have genomes with high guanine and cytosine content...
bacteria. The polyenes bind to ergosterol
Ergosterol
Ergosterol is a sterol found in fungi, and named for ergot, a common name for the members of the fungal genus Claviceps from which ergosterol was first isolated. Ergosterol does not occur in plant or animal cells...
in the fungal cell membrane and promote leakiness which may contribute to fungal cell death. Amphotericin B
Amphotericin B
Amphotericin B is a polyene antifungal drug, often used intravenously for systemic fungal infections...
, nystatin
Nystatin
Nystatin is a polyene antifungal medication to which many molds and yeast infections are sensitive, including Candida. Due to its toxicity profile, there are currently no injectable formulations of this drug on the US market...
, and natamycin
Natamycin
Natamycin , also known as pimaricin, is a naturally occurring antifungal agent produced during fermentation by the bacterium Streptomyces natalensis, commonly found in soil. Natamycin has a very low solubility in water, however, natamycin is effective at very low levels. Most molds have an MIC of...
are examples of polyene antimycotics.
Structures
Their chemical structureChemical structure
A chemical structure includes molecular geometry, electronic structure and crystal structure of molecules. Molecular geometry refers to the spatial arrangement of atoms in a molecule and the chemical bonds that hold the atoms together. Molecular geometry can range from the very simple, such as...
s feature a large ring of atoms (essentially a cyclic ester
Ester
Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...
ring) containing multiple conjugated carbon-carbon double bond
Double bond
A double bond in chemistry is a chemical bond between two chemical elements involving four bonding electrons instead of the usual two. The most common double bond, that between two carbon atoms, can be found in alkenes. Many types of double bonds between two different elements exist, for example in...
s (hence polyene
Polyene
Polyenes are poly-unsaturated organic compounds that contain one or more sequences of alternating double and single carbon-carbon bonds. These double carbon-carbon bonds interact in a process known as conjugation, which results in an overall lower energy state of the molecule.Organic compounds with...
) on one side of the ring and multiple hydroxyl
Hydroxyl
A hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...
groups bonded to the other side of the ring. Their structures also often have a d-mycosamine (a type of amino-glycoside) group bonded to the molecule. The series of conjugated double bonds typically absorbs strongly in the ultraviolet-visible region of the electromagnetic spectrum
Electromagnetic spectrum
The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. The "electromagnetic spectrum" of an object is the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object....
, often resulting in the polyene antibiotics having a yellow color.
Other examples of polyenes
- Rimocidin
- FilipinFilipinFilipin is a chemical compound. It was isolated by chemists at the Upjohn company in 1955 from the mycelium and culture filtrates of a previously unknown actinomycete, Streptomyces filipinensis, that was discovered in a soil sample collected in the Philippine Islands. Thus the name Filipin. The...
- Candicin
- HamycinHamycinHamycin is a polyene antimycotic organic compound described in India. It is a heptaene antifungal compound rather similar in chemical structure to amphotericin B except that it has an additional aromatic group bonded to the molecule. When pure, hamycin is a yellow, powdered solid...
- PerimycinPerimycinPerimycin is polyene antibiotic produced by Streptomyces coelicolor var. aminophilus. The compound exhibits antifungal properties.-Composition:...