Usnic acid
 |
|
| Names | |
|---|---|
|
IUPAC names
2,6-Diacetyl-7,9-dihydroxy-8,9b-dimethyl-1,3(2H,9bh)
-dibenzofurandione |
|
| Other names
usneine, usninic acid, usniacin
|
|
| Identifiers | |
|
[1] (racemic) 7562-61-0 (R)-(+)- 6159-66-6 (S)-(–)- 125-46-2 (racemic) 7562-61-0 (R)-(+)- 6159-66-6 (S)-(–)- 
|
|
| 3D model (Jmol) | Interactive image |
| ChEBI |
CHEBI:38319
|
| ChEMBL |
ChEMBL242022
|
| ChemSpider |
5444 
|
| ECHA InfoCard | 100.028.597 |
| PubChem | 5646 |
| UNII |
0W584PFJ77
|
|
|
|
|
| Properties | |
| C18H16O7 | |
| Molar mass | 344.315 g/mol |
| Melting point | 204 °C (399 °F; 477 K) |
|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|
|
 (what is ?) |
|
| Infobox references | |
Usnic acid is a naturally occurring dibenzofuran derivative found in several lichen species with the formula C18H16O7. It was first isolated by German scientist W. Knop in 1844 and first synthesized between 1933-1937 by Curd and Robertson. Usnic acid was identified in many genera of lichens including Usnea, Cladonia, Hypotrachyna, Lecanora, Ramalina, Evernia, Parmelia and Alectoria. Although it is generally believed that usnic acid is exclusively restricted to lichens, in a few unconfirmed isolated cases the compound was found in kombucha tea and non-lichenized ascomycetes.
At normal conditions, usnic acid is a bitter, yellow, solid substance. It is known to occur in nature in both the d- and l-forms as well as a racemic mixture. Salts of usnic acid are called usnates (e.g. copper usnate).
Usnic acid is a secondary metabolite in lichens whose role has not been completely elucidated. It is believed that usnic acid protects the lichen from adverse effects of sunlight exposure and deters grazing animals with its bitter taste.
Lichen extracts containing usnic acid have been utilized in medicine, perfumery, cosmetics, and ecology.
Usnic acid possesses a wide range of interesting biological properties. It is a potent antibiotic effective against Gram-positive bacteria, including Staphylococcus, , and Pneumococcus, other bacteria such as Mycobacterium tuberculosis, and some pathogenic fungi. It also exhibits antiviral, antiprotozoal, antimitotic, anti-inflammatory and analgesic activity. Other characteristics, like ultraviolet absorption, preserving properties, antigrowth, antiherbivore and anti-insect properties, have also been demonstrated.
...
Wikipedia