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.

CAS：7562-61-0
中文别名：D-松罗酸;D-地衣酸;D-2,6-二乙酰基-7,9-二羟基-8,9b-二甲基-1,3(2H,9bH)-二苯并呋喃二酮;右旋地衣酸;地衣酸;地衣酸,D-2,6-二;
英文别名：(9BR)-2,6-diacetyl-1,7,9-trihydroxy-8,9b-dimethyldibenzo[b,d]furan-3(9bH)-one;(+)-Usniacin;1,3(2H,9bH)-Dibenzofurandione, 2,6-diacetyl-7,9-dihydroxy-8,9b-dimethyl-, (9bR)-;
分子式：C18H16O7
分子量：344.315
精确质量：344.09
Psa：121.13
Logp：2.1266

MDL号：MFCD00016878

密度：1.54 g/cm3
沸点：605.4ºC at 760 mmHg
熔点：201-203°C(lit.)
闪点：223.3ºC
储存条件：2-8ºC

RTECS号：HP5295050
安全说明：S36
危险类别码：R22
WGK Germany：3
海关编码：2917399090
危险品标志：Xn