A polyene is an organic compound that contains two or more sequences of alternating single- and double-bonded carbon atoms. A double polyene is called a diene, a triple is a triene and one with four sequences is a tetraene. The term polyene is also used to apply to all anti-fungal antibiotics. They are also used to produce fatty acids and natural dyes.
In order to be a polyene, a fatty acid or organic compound must be unsaturated or poly-unsaturated. This means that the carbon atoms present in the fatty acid have at least one instance of where one of the carbon atoms has a double bond connecting it to another carbon atom. There can also be instances where such bonds are triple bonds. Each double or triple bond reduces the amount of hydrogen molecules or other particles a carbon atom can connect with by one and two, respectively.
In order for a molecule to be an organic compound, carbon must be present. A polyene is formed through the process of conjugation. This is a chemical reaction where the p-orbitals of atoms are connected by delocalized electrons. In order to be considered conjugation, these bonds must be alternating single and double bonds. If the carbon (C) atoms were put in a straight line, a diene would look like -C=C-C=C- and a triene would look like -C=C-C=C-C=C-.
Fatty acids are a common form of polyene. They are a type of carboxylic acid used in the metabolism process to create cellular energy through the process of fatty acid degradation. Fatty acids are often digested and absorbed through the intestines, where they are stored in adipose tissue until they need to be used.
Beta carotene is another conjugated organic compound. It is used as a red-orange pigment and is commonly found in fruits and vegetables. It is the reason why carrots are orange. It can be separated from the fruit or vegetable by column chromatography and is a source of pro-vitamin A. Overuse of beta carotene is connected with orange skin tones and more serious health risks when combined with activities such as smoking.
Polyenes such as nystatin and amphotericin are two of many types of polyene used to combat fungal infections. They are also the most effective. First studied in the 1950s, the anti-fungal antibiotics, known as polyene antimycotics, make fungal cell membranes more permeable to harmful ions and molecules. Amphotericin B is used to fight life-threatening mycoses, but a few fungal infections such as trichosporan are immune to its effects.