The Genus Cetraria s. str.-A Review of Its Botany, Phytochemistry, Traditional Uses and Pharmacology

The genus Cetraria s. str. (Parmeliaceae family, Cetrarioid clade) consists of 15 species of mostly erect brown or greenish yellow fruticose or subfoliose thallus. These Cetraria species have a cosmopolitan distribution, being primarily located in the Northern Hemisphere, in North America and in the Eurasia area. Phytochemical analysis has demonstrated the presence of dibenzofuran derivatives (usnic acid), depsidones (fumarprotocetraric and protocetraric acids) and fatty acids (lichesterinic and protolichesterinic acids). The species of Cetraria, and more particularly Cetraria islandica, has been widely employed in folk medicine for the treatment of digestive and respiratory diseases as decoctions, tinctures, aqueous extract, and infusions. Moreover, Cetraria islandica has had an important nutritional and cosmetic value. These traditional uses have been validated in in vitro and in vivo pharmacological studies. Additionally, new therapeutic activities are being investigated, such as antioxidant, immunomodulatory, cytotoxic, genotoxic and antigenotoxic. Among all Cetraria species, the most investigated by far has been Cetraria islandica, followed by Cetraria pinastri and Cetraria aculeata. The aim of the current review is to update all the knowledge about the genus Cetraria covering aspects that include taxonomy and phylogeny, morphology and distribution, ecological and environmental interest, phytochemistry, traditional uses and pharmacological properties.

Anti-Proliferative and Apoptotic Effects of Methanolic Extracts from Different Cladonia Species on Human Breast Cancer Cells

This study tries to elucidate the anti-proliferative and apoptotic effects of methanolic lichen extracts from Cladonia rangiformis and Cladonia convolute in MCF-7 human breast cancer cells. Lichen extracts (0-2 mg/ml) were added to MCF-7 cells for 24 h. Cell viability was tested using 3-(4,5-dimethylthiazol- 2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay. Cell proliferation was observed using bromodeoxyuridine (BrdU) labelling and proliferating cell nuclear antigen (PCNA) by immunocytochemistry. The TUNEL method was used for cell death detection. The effective dose (ED50) values of methanolic extracts from C. rangiformis and C. convolute were found to be 0.905 and 0.977 mg/ml, respectively. Treatment with C. rangiformis methanolic extract (0.2-0.8 mg/ml) dose-dependently inhibited proliferation of MCF-7 cells as detected by BrdU incorporation. The inhibition was started in 0.2 mg/ml concentration of C. convoluta methanolic extract. The percent of PCNA immunopositive cells showed a decrease in MCF-7 cells treated with two lichen extracts compared to control MCF-7. Both methanolic extracts showed a significant increase in percentage of apoptosis-positive cells. These results indicate that methanolic lichen extracts from C. rangiformis and C. convolute inhibited proliferation of MCF-7 cells and caused apoptosis in MCF-7 cells. The lichens may be novel natural agents for treating breast cancer disease.