No abstract

Plants are still to be explored for new anticancer compounds because overall success in cancer treatment is still not satisfactory. As a new possible source for such compounds, the lichens are recently taking a great attention. We, therefore, explored both the genotoxic and anti-growth properties of lichen species Parmelia sulcata Taylor. The chemical composition of P. sulcata was analyzed with comprehensive gas chromatography-time of flight mass spectrometry. Anti-growth effect was tested in human breast cancer cell lines (MCF-7 and MDA-MB-231) by the MTT and ATP viability assays, while the genotoxic activity was studied by assays for micronucleus, chromosomal aberration and DNA fragmentation in human lymphocytes culture. Cell death modes (apoptosis/necrosis) were morphologically assessed. P. sulcata inhibited the growth in a dose-dependent manner up to a dose of 100 lg/ml and induced caspase-independent apoptosis. It also showed genotoxic activity at doses ([125 lg/ml) higher than that required for apoptosis. These results suggest that P. sulcata may induce caspase-independent apoptotic cell death at lower doses, while it may be genotoxic at relatively higher doses.

In this study, methanolic extracts of Parmelia sulcata and Usnea filipendula induced apoptosis-like cell death by causing DNA damage, to cancer cells.

The aim of this study is to determine the chemical composition, and evaluate the genotoxic, and anti-growth potency of the methanol extracts of lichen species Hypogymnia physodes (L.) Nyl. (HPE).Anti-growth effect was tested in two different human breast cancer cell lines (MCF-7 and MDA-MB-231) by the MTT and ATP viability assays and apoptosis was assayed by the caspase-cleaved cytokeratin 18 (M30-antigen). Genotoxic activity of HPE was studied using chromosome aberration and micronuclei tests in human lymphocytes culture in vitro. The chemical composition of H. physodes was analyzed by using direct thermal desorption method coupled with comprehensive gas chromatography-time of flight mass spectrometry (GCXGC-TOF/MS). Our results indicate that HPE has an anti-growth effect at relatively lower concentrations, while relatively higher concentrations are required for genotoxic activity. HPE, therefore, seems to represent a therapeutic potential and poses new challenges for medicinal chemistry.

Three lichen species of Ramalina (R. farinacea, R. fastigiata and R. fraxinea) were examined. Evernic, fumarprotocetraric, lecanoric, stictic and usnic acid levels were determined by high performance liquid chromatography‐diode array detection. Acetone, methanol and ethanol were used to examine the efficiencies of different solvent systems for the extraction of lichen acids. The total phenol contents in the extracts were determined by the Folin–Ciocalteu method. The antioxidant capacities were determined by the ABTS (2,2′‐azino‐bis[3‐ethylbenzothiazoline‐6‐sulphonic acid]) method. The methanol extracts of the Ramalina species showed the highest antioxidant capacities. Broth microdilution testing was performed to determine the minimum inhibitory concentration (MIC) of the methanol extracts of the three Ramalina species. The MIC values of all extracts ranged from 64 to 512 μg/mL for all bacterial strains tested in this study. Practical Applications Lichens and their natural products are used worldwide for decorations, brewing and distilling, food, fodder, spice and natural remedies, and in the perfume and dying industries. Lichens produce a large number of phenolic compounds, such as depsides, depsidones and dibenzofurans. Lichens with antioxidant activity have increased abilities to scavenge toxic‐free radicals due to their phenolic groups. In recent years, many lichen substances have been found to have several biological activities. This article evaluates the antimicrobial and antioxidant activities and lichen acids of three Ramalina species. This is the first study to determine the stictic acid level in a R. farinacea extract and fumarprotocetraric acid and lecanoric acid levels in an R. fastigiata extract. The results of this study will contribute significantly to current knowledge regarding the utility of antimicrobial and antioxidant materials.