Натамицин

Описание

Natamycin is a naturally occurring macrolide polyene antifungal agent produced during fermentation by the bacterium S. natalensis, commonly found in soil. With minimal inhibitory concentrations ranging from 4-64 μM, natamycin is used to treat fungal infections, including Candida, Aspergillus, Cephalosporium, Fusarium, and Penicillium. Natamycin blocks fungal growth by binding specifically to ergosterol with an apparent affinity of ~100 μM, but it does not permeabilize cell membranes as other polyene antibiotics are known to do. Natamycin is also used in the food industry as a preservative.

Химические свойства

Natamycin (more commonly known as pimaricin) belongs to the polyene macrolide group of antifungal antibiotics. It was derived from Streptomyces natalensis or S. chattanoogensis. In therapeutic use, it is prescribed for a variety of fungal infections, mainly topically, but some ophthalmic applications as well. In addition to therapeutic and food use, pimaricin has applications including use as an agricultural chemical and wood preservative.
In the dry state, pimaricin is very stable, as long as it is protected from light and heat, and stability is maintained for a minimum of 1 to 2 years. As long as aqueous suspensions are stored in a cooland dark place, they can be kept for at least six months. Once placed on the surface of the cheese (pimaricin does not penetrate the surface of cheese as do sorbic acid salts), the antimycotic decomposes in about six weeks.

Использование

Natamycin (l), from Streptomyces nataIensis and Streptomyces chat tanoogensis, is used for the control of diseases of bulbs.

Биологические функции

Natamycin, also known as pimaracin, belongs to the polyene family of antibiotics; (a group of antifungal agents which target and bind to eukaryotic sterols and specifically ergosterol), and it is a secondary metabolite of Streptomyces natalensis . Very low levels (10–20 ppm) are needed to inhibit almost all yeasts and molds, while no amount of natamycin is sufficient to inhibit most bacteria, as they lack the sterol targeted by natamycin (some gram-positive types may be susceptible). Thus, natamycin may be used to retard the growth of fungi in meat products to which fermentative cultures are added, and is typically applied as a surface treatment (i.e., dip or spray). Resistant organisms are not typically encountered even though natamycin has been used as a food preservative for more than three decades. Unlike most bacteriocins, natamycin is toxic to eukaryotes. Acceptable daily intake of natamycin for humans is 0–0.3 mg/kg of body weight.

Антимикробная активность

The spectrum of Natamycin's activity is somewhat narrower than that of amphotericin and nystatin, but at the same time, it is less toxic. It exhibits especially pronounced activity against a few strains of Fusarium and Cefalosporium. Natamycin is a drug for treating superficial fungal infections, and it is used only for ophthalmologic purposes. Synonyms of this drug are pimafucin, pimaricin, tennecetin, and others.

Общее описание

Natamycin (pimaricin; Natacyn) is a polyene antibiotic obtainedfrom cultures of Streptomyces natalensis.The natamycin structure consists of a 26-membered lactonering containing a tetraene chromophore, an α,β-unsaturatedlactone carbonyl group, three hydroxyl groups, a carboxyl group, a trans epoxide, and a glycosidically joined mycosamine.Like the other polyene antibiotics, natamycin isamphoteric.The smaller polyenes are fungistatic and fungicidal within thesame concentration range.Natamycin possesses in vitro activity against severalyeasts and filamentous fungi, including Candida,Aspergillus, Cephalosporium, Penicillium, and Fusariumspp. The drug is supplied as a 5% ophthalmic suspension intendedfor the treatment of fungal conjunctivitis, blepharitis,and keratitis.

Побочные эффекты

Side effects that you should report to doctor as soon as possible:
allergic reactions like skin rash, itching or hives, swelling of the face, lips or tongue
changes in vision
eye pain
severe burning, stinging, or swelling of the eyelids
Side effects that usually do not require medical attention:
blurred vision for a few moments after application
temporary redness or stinging for a few moments after application
temporary watering of eyes

Профиль безопасности

Poison by intravenous, intramuscular, subcutaneous, and intraperitoneal routes. Moderately toxic by ingestion. When heated to decomposition it emits toxic fumes of NOx. Used as an antibacterial agent.