Antimicrobial and antioxidant potentials of non-cytotoxic extracts of corticolous lichens sampled in Armenia

Abstract

Due to wide range of secondary metabolites, lichens were used from antiquity as sources of colorants, perfumes and medicaments. This research focuses on exploring the antioxidant, antimicrobial and cytotoxic activities of methanol, ethanol, acetone extracts and aqueous infusions of corticolous lichens sampled from Armenia. Methanol, ethanol and acetone extracts from all tested lichens were active against Gram-positive bacterial strains. The most effective solvent to retrieve antimicrobial compounds was methanol. Aqueous infusions of tested lichens didn’t show any significant antibacterial and antifungal activity. The highest antimicrobial activity was observed for methanol extract of Ramalina sinensis. The minimum inhibitory concentration of methanol extract of Ramalina sinensis were 0.9–1.8 mg mL− 1. Pseudevernia furfuracea demonstrated antifungal activity (Ø 12 mm). Methanol extract of Parmelia sulcata demonstrated largest 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging activity (71 %). The cytotoxicity was measured on human HeLa (cervical carcinoma) cell lines using microculture tetrazolium test assay. The IC50 values estimated for methanol extracts of Peltigera praetextata, Evernia prunastri, Ramalina sinensis and Ramalina farinacea species in HeLa cell line were within 1.8–2.8 mg mL− 1 and considered as non-cytotoxic. Obtained results suggest that studied lichens can be prospective in biotechnologies as alternative sources of antimicrobial and antioxidant substances.

A review of the potential of lichen substances as antifungal agents: the effects of extracts and lichen secondary metabolites on Fusarium fungi

“…Laboratory in vitro studies on the potential of lichen secondary metabolites report their broad biological properties such as anticancer (Cardile et al 2017 ; Tripathi et al 2022 and literature cited therein), antioxidant (Hawrył et al 2020 ; Maulidiyah et al 2021 ), antimicrobial (Shiromi et al 2021 ; Sargsyan et al 2021 ), pro-health (Zhao et al 2021 and literature cited therein) or anti-fusarial potentials described in this meta-analysis.…”

A spectrophotometric analysis of extracted water-soluble phenolic metabolites of lichens

“…Additionally, the mycotoxins present in the lichens (Burkin and Kononenko 2014 , 2015 ) are mostly sparingly soluble in water (Santos et al 2022 ), thus reinforcing the health safety of potential water-based applications (cf. non-toxic water extracts: Kumar et al 2014 ).Many attempts in the laboratory to obtain lichen water extracts against fungi or bacteria have proved unsuccessful (e.g., Sargsyan et al 2021 ); although some of these provide a rationale for further research (macromycetes, genus Aspergillus and Fusarium : Furmanek et al 2022a , b , c and literature cited therein; yeast-like fungi: Furmanek and Seaward 2023 ), this requires qualification. From this perspective, the results of the present study show a promising direction for further laboratory research using extracted water-soluble phenolic metabolites.…”

Artículo de revisión. Ácido úsnico: alternativa potencial contra la resistencia bacteriana actual

“…Para estudiar las sustancias liquénicas, se debe hacer un aislamiento de las mismas, para ello se pueden emplear diferentes métodos de extracción y solventes orgánicos, ya que según la especie del liquen se obtendrán diferentes sustancias liquénicas, los principales disolventes que se utilizan son la acetona (C 3 H 6 O), el etanol (C 2 H 5 OH) y el metanol (CH 3 OH) [25], [6], para ello se toma el liquen, en especial el talo, que es la parte en la que se encuentra una mayor cantidad de la sustancia, representando alrededor del 10% del peso del talo seco [20]. Las sustancias liquénicas denominadas extractos metanólicos, siendo el metanol el solvente utilizado para su extracción, hacen parte de los dépsidos, depsidonas y dibenzofuranos [26].…”