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Ergosterol
IUPAC name ergosta-5,7,22-trien-3β-ol
Identifiers
CAS number	57-87-4 Y
PubChem	4835
EC number	200-352-7
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	396.65 g/mol
Exact mass	396.339216
Melting point	160.0 °C
Boiling point	250.0 °C
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Ergosterol (ergosta-5,7,22-trien-3β-ol), a sterol, is a biological precursor (a provitamin) to vitamin D₂. It is turned into viosterol by ultraviolet light, and is then converted into ergocalciferol, which is a form of vitamin D.^[1]

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 present in the cell membranes of some protists, such as trypanosomes.^[2] 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 physically to ergosterol within the membrane , and thus creates a polar pore in fungal membranes. This causes ions (predominantly potassium and protons) and other molecules to leak out, which will kill the cell.^[3] Amphotericin B has been replaced by safer agents in most circumstances but is still used, despite its side effects, for life-threatening fungal or protozoa infections.

Miconazole, Itraconazole, and Clotrimazole work in a different way, inhibiting synthesis of ergosterol from lanosterol. Ergosterol is a smaller molecule than lanosterol; it is synthesized by combining two molecules of farnisyl pyrophosphate, a 15 carbon long protein into lanosterol which has 30 carbons. Then two carbon groups are clipped off, making ergosterol. The " azoles" inhibit one of the enzymes which removes a methyl from lanosterol, one of the steps between lanosterol and 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.

Research has shown ergosterol may have anti-tumor properties.^[4][5]

Ergosterol powder is an irritant to skin, eyes, and the respiratory tract. Ingestion of large amounts can cause hypercalcemia, which (if prolonged) can lead to calcium salt deposits in the soft tissues, and particularly the kidneys.^[6]

References

External links

• Safety (MSDS) data for ergosterol Oxford University (2005)