R amalina Lichens and Their Major Metabolites as Possible Natural Antioxidant and Antimicrobial Agents

Abstract

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.

UHPLC‐HRMS/MS Based Profiling of Algerian Lichens and Their Antimicrobial Activities

“…[51] Likewise, Tay et al reported a MIC value of 132 lg/mL on both microorganisms. [53] MIC values of the methanolic extracts of both Ramalina species obtained by Sahin et al [52] against several bacterial strains (E. coli and S.aureus) ranged from 64 to 512 lg/mL. Thus, the Algerian Ramalina active extracts studied here seem to be more active on the same tested organisms.…”

“…For instance, Esimone et al reported the MIC values for the R. farinacea hexanic extract of 199.53 lg/mL and of 125.89 lg/mL on C. albicans and S. aureus, respectively. [53] MIC values of the methanolic extracts of both Ramalina species obtained by Sahin et al [52] against several bacterial strains (E. coli and S.aureus) ranged from 64 to 512 lg/mL. [53] MIC values of the methanolic extracts of both Ramalina species obtained by Sahin et al [52] against several bacterial strains (E. coli and S.aureus) ranged from 64 to 512 lg/mL.…”

Neuroprotective and Anti-Inflammatory Effects of Evernic Acid in an MPTP-Induced Parkinson’s Disease Model

“…Studies have reported EA is biologically active and that it severely inhibits the growths of the pathogenic fungi Pythium ultimum and Phytophthora infestans [ 15 ]. Another study showed that EA extracted from Ramalina fastigiata has antioxidant capacity and an antimicrobial effect on E. coli [ 16 ]. Others reported EA inhibits the proliferations of U-87 human glioblastoma cells and HeLa cells (a cervical cancer cell line) [ 17 , 18 ].…”

Biological evaluation and phytochemical profiling of some lichen species

“…Among the tested lichen species, the methanol extract of R. fastigiata showed the best antibacterial activity with inhibition against 6 out of 7 bacteria. Preceding studies (Cansaran et al, 2007;Şahin et al, 2015;Ristic et al, 2016) reported that acetone extract of R. fastigiata showed effect against E. coli and S. aureus. Here, the antibacterial activity of R. fastigiata against S. epidermidis, S. pyogenes, P. vulgaris, K. pneumonia, and E. cloacae was investigated for the first time.…”