Ergosterol

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Ergosterol

IUPAC name	(3S,9S,10R,13R,14R,17R)-17-((2R,5R,E)-5,6- dimethylhept-3-en-2-yl)-10,13- dimethyl-2,3,4,9,10,11,12,13,14,15,16,17- dodecahydro-1H-cyclopenta[a]phenanthren-3-ol
Identifiers
CAS number	[57-87-4]
MeSH	Ergosterol
SMILES	CC(C)[C@@H](C)C=C[C@@H] (C)[C@H]1CC[C@H]2C3=C C=C4C[C@@H](O)CC[C@]4 (C)[C@H]3CC[C@]12C
InChI	1/C28H44O/c1-18(2) 19(3)7-8-20(4)24-11-12- 25-23-10-9-21-17-22(29) 13-15-27(21,5)26(23)14- 16-28(24,25)6/h7-10, 18-20,22,24-26,29H,11- 17H2,1-6H3/b8-7+/t19-, 20+,22-,24+,25-,26-, 27-,28+/m0/s1
Properties
Molecular formula	C₂₈H₄₄O
Molar mass	396.66 g/mol
Melting point	160.0 °C
Boiling point	250.0 °C
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Ergosterol (ergosta-5,7,22-trien-3β-ol), a sterol, is a biological precursor to Vitamin D₂. It is turned into viosterol by ultraviolet light, and is then converted into ergocalciferol, which is a form of Vitamin D.

Ergosterol is a component of fungal cell membranes, serving the same function that cholesterol serves in animal cells. The presence of ergosterol in fungal cell membranes coupled with its absence in animal cell membranes makes it a useful target for antifungal drugs. Ergosterol is also used as a fluidizer in the cell membranes of some protists, such as trypanosomes. This is the basis for the use of some antifungals against West African sleeping sickness. Amphotericin B is an antifungal drug that targets ergosterol. It binds to ergosterol and creates a polar pore in fungal membranes. This causes ions (predominantly K⁺ and H⁺) and other molecules to leak out of the cell, killing it. Amphotericin B has been replaced by safer agents in most circumstances but is still used, despite its side effects, for life-threatening fungal infections. Miconazole,Clotrimazole also inhibit synthesis of ergosterol.

Ergosterol is also used as an indicator of fungal biomass in soil. Though ergosterol does degrade over time, if kept below freezing in a dark environment, this degradation can be slowed or even stopped completely.