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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. Previously, polyenes were thought to bind to ergosterol in the fungal cell membrane and thus weakening it and causing leakage of K+ and Na+ ions, which could contribute to fungal cell death. However, more detailed studies of polyene molecular properties have challenged this model suggesting that polyenes instead bind and extract ergosterol directly from the cellular membrane thus disrupting the many cellular functions ergosterols perform. 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 (in essence, a cyclic ester ring) containing multiple conjugated carbon-carbon double bonds (hence ''polyene'') on one side of the ring and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antimicrobial
An antimicrobial is an agent that kills microorganisms or stops their growth. Antimicrobial medicines can be grouped according to the microorganisms they act primarily against. For example, antibiotics are used against bacteria, and antifungals are used against fungi. They can also be classified according to their function. Agents that kill microbes are microbicides, while those that merely inhibit their growth are called bacteriostatic agents. The use of antimicrobial medicines to treat infection is known as antimicrobial chemotherapy, while the use of antimicrobial medicines to prevent infection is known as antimicrobial prophylaxis. The main classes of antimicrobial agents are disinfectants (non-selective agents, such as bleach), which kill a wide range of microbes on non-living surfaces to prevent the spread of illness, antiseptics (which are applied to living tissue and help reduce infection during surgery), and antibiotics (which destroy microorganisms within the body). The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycoside
In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. These can be activated by enzyme hydrolysis, which causes the sugar part to be broken off, making the chemical available for use. Many such plant glycosides are used as medications. Several species of ''Heliconius'' butterfly are capable of incorporating these plant compounds as a form of chemical defense against predators. In animals and humans, poisons are often bound to sugar molecules as part of their elimination from the body. In formal terms, a glycoside is any molecule in which a sugar group is bonded through its anomeric carbon to another group via a glycosidic bond. Glycosides can be linked by an O- (an ''O-glycoside''), N- (a ''glycosylamine''), S-(a ''thioglycoside''), or C- (a '' C-glycoside'') glycosidic bond. According to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antifungals
An antifungal medication, also known as an antimycotic medication, is a pharmaceutical fungicide or fungistatic used to treat and prevent mycosis such as athlete's foot, ringworm, candidiasis (thrush), serious systemic infections such as cryptococcal meningitis, and others. Such drugs are usually yes obtained by a doctor's prescription, but a few are available over the counter (OTC). Types of antifungal There are two types of antifungals: local and systemic. Local antifungals are usually administered topically or vaginally, depending on the condition being treated. Systemic antifungals are administered orally or intravenously. Of the clinically employed azole antifungals, only a handful are used systemically. These include ketoconazole, itraconazole, fluconazole, fosfluconazole, voriconazole, posaconazole, and isavuconazole. Examples of non-azole systemic antifungals include griseofulvin and terbinafine. Classes Polyenes A polyene is a molecule with multiple conjugated do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perimycin
Perimycin, also known as aminomycin and fungimycin, is polyene antibiotic produced by ''Streptomyces coelicolor'' var. aminophilus. The compound exhibits antifungal properties. __TOC__ Composition Perimycin is produced naturally as a mixture of three types: A, B and C, with type A being the major component. All types consist of a polyketide core with a perosamine sugar moiety. The variations occur at the end of the core opposite the perosamine moiety. Perimycin A has an aromatic group in this position, whereas the identities of the analogous groups in the other perimycin types are currently undetermined. Usage Polyene antibiotics in general are often toxic to humans and have poor bioavailability. Thus, with the notable exception of amphotericin B Amphotericin B is an antifungal medication used for serious fungal infections and leishmaniasis. The fungal infections it is used to treat include mucormycosis, aspergillosis, blastomycosis, candidiasis, coccidioidomycosis, and crypt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamycin
Hamycin is a pair polyene antimycotic organic compounds 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. There are two versions of hamycin with very similar chemical structures: hamycin A and hamycin B. __TOC__ Sources Hamycin is obtained from a strain of streptomyces bacteria growing in soil i.e., ''Streptomyces pimprina''. This compound is being produced in India by Hindustan Antibiotics Limited, located at Pimpri, Pune, Maharashtra, India. It is similar to nystatin and it is more water-soluble. Uses It is useful as an antifungal antibiotic drug for topical as well as systemic mycoses Fungal infection, also known as mycosis, is disease caused by fungi. Different types are traditionally divided according to the part of the body affected; superficial, subcutaneous, and systemic. Superficial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filipin
Filipin is a mixture of chemical compounds first isolated by chemists at the Upjohn company in 1955 from the mycelium and culture filtrates of a previously unknown actinomycete, '' Streptomyces filipinensis''. It was discovered in a soil sample collected in the Philippine Islands, hence the name filipin. The isolate possessed potent antifungal activity. It was identified as a polyene macrolide based on its characteristic UV-Vis and IR spectra. Functions Although the polyene macrolide antibiotics exhibit potent antifungal activity, most are too toxic for therapeutic applications, with the exceptions of amphotericin B and nystatin A1. Unlike amphotericin B and nystatin A1 which form sterol-dependent ion channels, filipin is thought to be a simple membrane disrupter. Since filipin is highly fluorescent and binds specifically to cholesterol, it has found widespread use as a histochemical stain for cholesterol. This method of detecting cholesterol in cell membranes is used clin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyketide Synthase
Polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone (or reduced forms of a ketone) and methylene groups: (-CO-CH2-). First studied in the early 20th century, discovery, biosynthesis, and application of polyketides has evolved. It is a large and diverse group of secondary metabolites caused by its complex biosynthesis which resembles that of fatty acid synthesis. Because of this diversity, polyketides can have various medicinal, agricultural, and industrial applications. Many polyketides are medicinal or exhibit acute toxicity. Biotechnology has enabled discovery of more naturally-occurring polyketides and evolution of new polyketides with novel or improved bioactivity. History Naturally produced polyketides by various plants and organisms have been used by humans since before studies on them began in the 19th and 20th century. In 1893, J. Norman Collie synthesized detectable amounts of orcinol by heating dehy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natamycin
Natamycin, also known as pimaricin, is an antifungal medication used to treat fungal infections around the eye. This includes infections of the eyelids, conjunctiva, and cornea. It is used as eyedrops. Natamycin is also used in the food industry as a preservative. Allergic reactions may occur. It is unclear if medical use during pregnancy or breastfeeding is safe. It is in the macrolide and polyene families of medications. It results in fungal death by altering the cell membrane. Natamycin was discovered in 1955 and approved for medical use in the United States in 1978. It is on the World Health Organization's List of Essential Medicines. It is produced by fermentation of certain types of the bacterium ''Streptomyces''. Uses Medical Natamycin is used to treat fungal infections, including '' Candida'', ''Aspergillus'', ''Cephalosporium'', ''Fusarium'', and ''Penicillium''. It is applied topically as a cream, in eye drops, or (for oral infections) in a lozenge. Natamyc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nystatin
Nystatin, sold under the brandname Mycostatin among others, is an antifungal medication. It is used to treat '' Candida'' infections of the skin including diaper rash, thrush, esophageal candidiasis, and vaginal yeast infections. It may also be used to prevent candidiasis in those who are at high risk. Nystatin may be used by mouth, in the vagina, or applied to the skin. Common side effects when applied to the skin include burning, itching, and a rash. Common side effects when taken by mouth include vomiting and diarrhea. During pregnancy use in the vagina is safe while other formulations have not been studied in this group. It works by disrupting the cell membrane of the fungal cells. Nystatin was discovered in 1950 by Rachel Fuller Brown and Elizabeth Lee Hazen. It was the first polyene macrolide antifungal. It is on the World Health Organization's List of Essential Medicines. It is available as a generic medication. It is made from the bacterium '' Streptomyces noursei'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
