Review of pharmacological studies of Mongolian medicine Usnea longissima Ach / Монголын эм зүй, эм судлал

Introduction@#Lichen is a stable symbiotic complex formed by fungi and symbiotic algae. There are many kinds of lichens, which are cold and drought resistant, and have strong adaptability to the environment. Lichens can grow and reproduce in places where other organisms are difficult to survive. Apart from their ecological importance, they have become important natural medicinal resources due to the production of a large number of unique secondary metabolites (depsides, depsidones, dibenzofurans, pulvinic acid derivatives) and pigments (anthraquinones, napthoquinones, and xanthones) which can act as biomarkers as well as bioactive compounds. <i>Usnea longissima Ach</i>. is a hanging hair lichen, that grows circumpolar in high humidity inland areas and coastal forests of Europe, Asia, and North America. This lichen has been used therapeutically for centuries in Mongolian traditional systems of medicine for its analgesic, cardiotonic, stomachic, and wound healing properties. Recently, many scholars have studied the chemical constituents and biological activities of <i>Usnea longissima Ach</i> and its related varieties, and obtained gratifying results. Previous studies on its chemical constituents have resulted in isolation of several bioactive secondary metabolites which include monosubstituted phenyls, depsides, anthraquinones, dibenzofuran derivatives, and terpenoids. In order to understand the clinical application and devote to the deeper scientific research and development, the pharmacological literature of <i>Usnea longissima Ach</i> was sorted out in this study. @*Methods@#Collect and sort out the modern periodical literature and the related pharmacological studies of Usnea longissima Ach in academic websites. @*Result and Conclusion@#The pharmacological studies of Mongolian medicine <i>Usnea longissima Ach</i> were studied in this paper. <i>Usnea longissima Ach</i> has a long history of medicinal use, which is recorded in the traditional medical materials of Tibetan, Mongolian, Uygurs, Tai and other ethnic minorities, as well as traditional Chinese medicine. According to the records, different nationalities in different countries have their own traditional medical theories as the basis for the diagnosis and treatment of different diseases. Previous studies on its chemical constituents have resulted in isolation of several bioactive secondary metabolites which include monosubstituted phenyls, depsides, anthraquinones, dibenzofuran derivatives, and terpenoids. The <i>Usnea longissima Ach</i> tastes bitter and it has the function of anti-bacterial, antioxidant, anti-cancer and detoxification effects. But it requires further study such as extract, isolate, and analyze the more chemical ingredients and its pharmacological activity.

Three New Non-reducing Polyketide Synthase Genes from the Lichen-Forming Fungus Usnea longissima

Usnea longissima has a long history of use as a traditional medicine. Several bioactive compounds, primarily belonging to the polyketide family, have been isolated from U. longissima. However, the genes for the biosynthesis of these compounds are yet to be identified. In the present study, three different types of non-reducing polyketide synthases (UlPKS2, UlPKS4, and UlPKS6) were identified from a cultured lichen-forming fungus of U. longissima. Phylogenetic analysis of product template domains showed that UlPKS2 and UlPKS4 belong to group IV, which includes the non-reducing polyketide synthases with an methyltransferase (MeT) domain that are involved in methylorcinol-based compound synthesis; UlPKS6 was found to belong to group I, which includes the non-reducing polyketide synthases that synthesize single aromatic ring polyketides, such as orsellinic acid. Reverse transcriptase-PCR analysis demonstrated that UlPKS2 and UlPKS4 were upregulated by sucrose; UlPKS6 was downregulated by asparagine, glycine, and alanine.

In-vitro antibacterial screening of extracts of usnea longissima lichen.

Objective: To evaluate the antibacterial activity of the hydroalcoholic and ethanolic extracts of the Usnea longissima lichen. Material and methods: Kirby Bauer's disk diffusion method and broth serial dilution tests according to CLSI Guidelines (2000) were used, to find out the antibacterial effect of the 50% Hydro-ethanolic and 90% ethanolic extracts of the selected lichen. The efficacy of the extracts were measured after the period of incubation as Zone of Inhibition (ZOI) in mm compared with the Standard drug used i.e. Ciprofloxacin for Gram positive and Gentamicin for Gram negative bacterial strains. MIC was further tested for susceptible organisms. DMSO was used as control. All the experiments were conducted in triplicates and in proper sterilized condition Results: It was found that Usnea longissima has a significant activity towards Bacillus cereus (ZOI 25-26 mm as compared to Ciprofloxacin ZOI-23 mm) MIC-0.625 mg/ml, Pseudomonas aeruginosa (ZOI 20-27 mm as compared to Gentamicin ZOI-14 mm) MIC- 1.25 mg/ml and Proteus vulgaris (ZOI of 13 - 16 mm where as Gentamicin produced ZOI as 14 mm) MIC 2.5 mg/ml. Moderate activity was shown towards Staphylococcus aureus, Corynebacterium xerosis, Escherichia coli and Klebseilla pneuomoniae while no activity towards S. epidermidis and S. pyrogenes. Moreover it was seen that 50% Hydro-ethanolic extracts produced more significant ZOI than ethanolic extract in all tested strains. Conclusions: U. longissima contains potent chemical constituents as Usnic acid which can halt infection and is effective against various gram-positive and gram-negative bacterial species. It can be concluded that due to their antimicrobial effects extracts of the lichen can be used for the infectious diseases caused by these microbes. This study provides an in-vitro proof of the antibacterial activity of Usnea longissima.