[Oral acute toxicity of (+)-usnic acid in mice and its cytotoxicity in rat cardiac fibroblasts].
OBJECTIVE
To observe the oral acute toxicity of of (+)-usnic acid in mice and assess its cytotoxicity in rat cardiac fibroblasts.


METHODS
The mice with acute poisoning of (+)-usnic acid at different doses by oral administration were observed for toxic manifestations, and the LD(50) was determined. The survival time and survival rate of the mice receiving different doses of (+)-usnic acid were observed. Cultured rat cardiac fibroblasts were inoculated with different concentrations of (+)-usnic acid, and the cell growth inhibition rate was estimated and the IC(50) determined using MTT assay.


RESULTS
Higher dose of (+)-usnic acid resulted in more obvious symptoms of poisoning and shorter survival time of the mice. The LD(50) of (+)-usnic acid in mice by oral administration was 388 mg/kg. The manifestations of poisoning such as apathism, pilomotor, chill, dyspnea, torpidity and anorexia was observed. Rat cardiac fibroblasts incubated with (+)-usnic acid showed obvious growth inhibition, which was positively correlated to the dose of (+)-usnic acid, and high dose of (+)-usnic acid caused severe cell injuries. The IC(50) of (+)-usnic acid in rat cardiac fibroblasts was 322 microg/ml.


CONCLUSIONS
(+)-usnic acid is a natural compound of low toxicity in mice, and low to medium dose of (+)-usnic acid dose not produce obvious cytotoxicity.
Cheng
Yan-bin
YB
Department of Immunology, Xi'an Jiaotong University College of Medicine, Xi'an 710061, China. chengyb@mail.xjtu.edu.cn
Wei
Lin-lin
LL
Gu
Ning
N
Si
Kai-wei
KW
Shi
Lin
L
Li
Xiao-qi
XQ
Li
Chen
C
Yuan
Yu-kang
YK
D000284:Administration, Oral; D000818:Animals; D001572:Benzofurans / Q000008:administration & dosage / Q000737:chemistry* / Q000633:toxicity*; D005347:Fibroblasts / Q000187:drug effects*; D007928:Lethal Dose 50; D051379:Mice; D009206:Myocardium / Q000166:cytology*; D051381:Rats; D013237:Stereoisomerism
D001572:Benzofurans; C073339:usnic acid