Seven species of lichens such us Umbilicaria aff. calvescens, Hypotrachyna enderythraea, Punctelia graminicola, Cladonia chlorophaea, Xanthoparmelia farinose, Psiloparmelia distincta (rock and tree substrates; rs and ts), and Usnea durietzii were collected from the province of Arequipa - Peru. Their usnic acid (UA) and fatty acid (FA) amounts in methanol-acetone were determined by High-performance liquid chromatography with diode-array detection (HPLC-DAD) and Gas chromatography-flame ionization detector (GC-FID). The antimicrobial activities of these extracts were evaluated against Staphylococcus aureus ATCC strains (43300, 29213, 25923 and 700699), Escherichia coli strains (O157:H7 and ATCC 10536), Salmonella enterica sv typhimurium ATCC 14028, Candida albicans ATCC 90028 and Candida. tropicalis ATCC 750T. In addition, antioxidant capacity was also studied by Total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical, 2,2-Azino-bis-3-ethylbenzothiazoline-6-sulfonic Acid (ABTS) radical cation and Ferric Reducing Antioxidant Power (FRAP) assays. The UA contents in all the studied lichen species varied between 0.017 and 0.304 %. Among all the tested extracts, Usnea durietzii had the highest total FA concentration (5.81 mg/g). P. distincta (rs) was active against S. aureus strains (MIC = 0.02–0.2 mg/mL) as well as C. albicans (MIC = 4 mg/mL) and C. tropicalis (MIC = 3 mg/mL). P. distincta (ts) displayed moderate total phenol content (TPC = 29.1 ± 1.6 mg GAE/g) and antioxidant capacity evidenced by scavenging DPPH (IC₅₀ = 1.45 ± 0.03 mg/mL) and ABTS (18.2 ± 0.2 mg TE/g) radicals, but it showed high values of FRAP (1953 ± 87 μM Fe²⁺/g). Our findings indicate that P. distincta (rs) could be considered as a potential antimicrobial metabolites source whereas P. distincta (ts) and Puntelia graminicole for polyphenols with antioxidant compound.

In this study, sixteen secondary metabolites, including two chromones, four dibenzofurans, three lipids, three depsides, two aromatic compounds, a quinone, and a terpene, were detected in the methanol:acetone (1:1 v/v) extract of the lichen Hypotrachyna enderythraea (Zahlbr.) Hale, using High-Performance Liquid Chromatography coupled to Orbitrap Electrospray Ionization tandem Mass Spectrometry (HPLC-Orbitrap ESI tandem MS/MS). These metabolites were characterized by analysis of their exact molecular masses and corresponding fragmentation patterns. The retention times of the identified metabolites were compared with those of standard compounds, confirming the presence of naturally occurring bioactive compounds. Density Functional Theory (DFT) calculations were employed to investigate preferential deprotonation sites in representative polyprotic metabolites. All these findings may contribute to expanding the spectrum of compounds identified within the genus Hypotrachyna and to evaluating their potential biological activities.

[This corrects the article DOI: 10.1016/j.heliyon.2024.e39703.].