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| Names | |
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| IUPAC name (22E)-Ergosta-5,7,22-trien-3β-ol | |
| Systematic IUPAC name (1R,3aR,7S,9aR,9bS,11aR)-1-[(2R,3E,5R)-5,6-Dimethylhept-3-en-2-yl]-7-hydroxy-9a,11a-dimethyl-2,3,3a,6,7,8,9,9a,9b,10,11,11a-dodecahydro-1H-cyclopenta[a]phenanthren-7-ol | |
| Identifiers | |
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3D model (JSmol) | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
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| ECHA InfoCard | 100.000.320 |
| EC Number |
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| MeSH | Ergosterol |
| UNII | |
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| Properties | |
| C28H44O | |
| Molar mass | 396.65 g/mol |
| Melting point | 160 °C (320 °F; 433 K) |
| Boiling point | 250 °C (482 °F; 523 K) |
| −279.6·10−6 cm3/mol | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Ergosterol (ergosta-5,7,22-trien-3β-ol) is amycosterol found incell membranes offungi andprotozoa, serving many of the same functions thatcholesterol serves inanimalcells. Because many fungi and protozoa cannot survive without ergosterol, theenzymes that synthesize it have become important targets fordrug discovery. In human nutrition, ergosterol is aprovitamin form ofvitamin D2; exposure toultraviolet (UV) light causes a chemical reaction that producesvitamin D2.
Ergosterol (ergosta-5,7,22-trien-3β-ol) is asterol found in fungi, and named afterergot, the common name of members of the fungal genusClaviceps from which ergosterol was first isolated. Ergosterol is a component ofyeast and otherfungalcell membranes, serving many of the same functions that cholesterol serves in animal cells.[1]Its specificity in higher fungi is thought to be related to the climatic instabilities (highly varying humidity and moisture conditions) encountered by these organisms in their typical ecological niches (plant and animal surfaces, soil). Thus, despite the added energy requirements of ergosterol synthesis (if compared to cholesterol), ergosterol is thought to have evolved as a nearly ubiquitous, evolutionarily advantageous fungal alternative to cholesterol.[2] This advantage could be linked to the presence of two conjugated double bonds in the structure (B-ring) of ergosterol giving it antioxidant properties.[3] Additionally, the structure of ergosterol appears to have been finely tuned towards optimal interaction with saturated lipids.[4]
Because ergosterol is present in cell membranes of fungi, yet absent in those of animals, it is a useful target forantifungal drugs. Ergosterol is also present in the cell membranes of some protists, such astrypanosomes.[5] This is the basis for the use of some antifungals against West Africansleeping sickness.
Amphotericin B, an antifungal drug, targets ergosterol. It binds physically to ergosterol within the membrane, thus creating a polar pore in fungal membranes. This causes ions (predominantlypotassium andprotons) and other molecules to leak out, which will kill the cell.[6] Amphotericin B has been replaced by safer agents in most circumstances, but is still used, despite its side effects, for life-threatening fungal or protozoan infections.
Fluconazole,miconazole,itraconazole,clotrimazole, andmyclobutanil work in a different way, inhibiting synthesis of ergosterol fromlanosterol by interfering with14α-demethylase.[7] Ergosterol is a smaller molecule than lanosterol; it is synthesized by combining two molecules of farnesyl pyrophosphate, a 15-carbon-long terpenoid, into lanosterol, which has 30 carbons. Then, two methyl groups are removed, making ergosterol. The "azole" class of antifungal agentsinhibit the enzyme that performs thesedemethylation steps in the biosynthetic pathway between lanosterol and ergosterol.[7]
Some protozoa, includingTrichomonas andLeishmania are inhibited by drugs that target ergosterol synthesis and function[8]
Ergosterol is abiological precursor ofvitamin D2, the chemical name of which isergocalciferol. Exposure ofwhite button mushrooms toUV-C irradiation produces time-dependent increases in vitamin D2 concentrations in the mushrooms.[9][10] Fungi are grown industrially to enable ergosterolextraction and preparation as a powder for sale as a vitamin D2dietary supplement andfood additive.[11]
Preparations of irradiated ergosterol containing a mixture of previtamin and vitamin D2 were calledviosterol in the 1930s.[12]
Ergosterol powder is an irritant to skin, eyes, and the respiratory tract. Ingestion of large amounts can causehypercalcemia, which (if prolonged) can lead to calcium salt deposits in the soft tissues and kidneys.[13]
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