Polyene antimycotic
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 thus weakens it, causing leakage of K+ and Na+ ions, which may contribute to fungal cell death. Amphotericin B, nystatin, and natamycin are examples of polyene antimycotics. They are a subgroup of macrolides.Structures
Their chemical structures feature a large ring of atoms containing multiple conjugated carbon-carbon double bonds 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 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.
. Amphotericin B is an example of a yellow polyene antimycotic agent. Note the alternating double and single bonds in the center and the mycosamine group in the bottom-right corner.
.
, sometimes called pimaricin.Biosynthesis
The natural route to synthesis includes polyketide synthase components.Other examples of polyenes
