Research progress on chemical constituents and their bioactivities of Usnea lichens / 中草药

ABSTRACT

Usnea lichens, as traditional Chinese medicine, has an extraordinary long history. It is well known for its medicinal uses due to the unique symbiosis of bacteria and algae. The symbiosis promotes the unique medicinal values. Its traditional functions involve clearing heat and detoxifying, relaxing tendon and activating blood, clearing liver and improving eyesight, relieving cough and eliminating phlegm, etc. They are mainly used for treating diseases such as phlegm malaria, infection, trauma, etc. They can cure plague, edema, and other diseases in the formula. Usnea lichens contain secondary metabolites such as multi-substituted monobenzenes, dibenzofurans, depsides, etc. Dibenzofurans and depsides are the main active ingredients. The crude extracts and compounds derived from Usnea lichens possess potent antimicrobial, antitumor, lipid-lowering, and liver-protecting activities. This paper reviews the research progress on the chemical constituents and biological activities of Usnea lichens in recent years, which provides reference values for further development and utilization of them.