Anthelmintic and antimicrobial activities of three new depsides and ten known depsides and phenols from Indonesian lichen: Parmelia cetrata Ach

Antarctic fungi produce pigment with antimicrobial and antiparasitic activities

Natural pigments have received special attention from the market and industry as they could overcome the harm to health and the environmental issues caused by synthetic pigments. These pigments are commonly extracted from a wide range of organisms, and when added to products they can alter/add new physical-chemical or biological properties to them. Fungi from extreme environments showed to be a promising source in the search for biomolecules with antimicrobial and antiparasitic potential. This study aimed to isolate fungi from Antarctic soils and screen them for pigment production with antimicrobial and antiparasitic potential, together with other previously isolated strains A total of 52 fungi were isolated from soils in front of the Collins Glacier (Southeast border). Also, 106 filamentous fungi previously isolated from the Collins Glacier (West border) were screened for extracellular pigment production. Five strains were able to produce extracellular pigments and were identified by ITS sequencing as Talaromyces cnidii, Pseudogymnoascus shaanxiensis and Pseudogymnoascus sp. All Pseudogymnoascus spp. (SC04.P3, SC3.P3, SC122.P3 and ACF093) extracts were able to inhibit S. aureus ATCC6538 and two (SC12.P3, SC32.P3) presented activity against Leishmania (L.) infantum, Leishmania amazonensis and Trypanossoma cruzii. Extracts compounds characterization by UPLC-ESI-QToF analysis confirmed the presence of molecules with biological activity such as: Asterric acid, Violaceol, Mollicellin, Psegynamide A, Diorcinol, Thailandolide A. In conclusion, this work showed the potential of Antartic fungal strains from Collins Glacier for bioactive molecules production with activity against Gram positive bacteria and parasitic protozoas.

Antioxidant activity and enzymatic of lichen substances: A study based on cyclic voltammetry and theoretical

The antioxidant activity of nine lichen substances, including methylatrarate (1), methyl haematommate (2), lobaric acid (3), fumarprotocetraric acid (4), sphaerophorin (5), subsphaeric acid (6), diffractaic acid (7), barbatolic acid (8) and salazinic acid (9) has been determined through cyclic voltammetry. The compounds 1-4 presented slopes close to the Nernst constant of 0.059 V, indicating a 2H⁺/2e^- relation between protons and electrons, as long as the compounds 5, 6, 7, 8, and 9 present slopes between 0.037 V and 0.032 V, indicating a 1H⁺/2e^- relation between protons and electrons. These results show a high free radical scavenging activity by means of the release of H⁺, suggesting an important antioxidant capacity of these molecules. Theoretical calculations of hydrogen bond dissociation enthalpies (BDE), proton affinities (PA), and Proton Transfer (PT) mechanisms, at M06-2x/6-311+G(d,p) level complement the experimental results. Computations support that the best antioxidant activity is obtained for the molecules (3, 4, 5, 6, 7 and 8), that have a carboxylic acid group close to a phenolic hydroxyl group, through hydrogen atomic transfer (HAT) and sequential proton loss electron transfer (SPLET) mechanisms. Additional computations were performed for modelling binding affinity of the lichen substances with CYPs enzymes, mainly CYP1A2, CYP51, and CYP2C9*2 isoforms, showing strong affinity for all the compounds described in this study.

Lichen Depsides and Tridepsides: Progress in Pharmacological Approaches

Depsides and tridepsides are secondary metabolites found in lichens. In the last 10 years, there has been a growing interest in the pharmacological activity of these compounds. This review aims to discuss the research findings related to the biological effects and mechanisms of action of lichen depsides and tridepsides. The most studied compound is atranorin, followed by gyrophoric acid, diffractaic acid, and lecanoric acid. Antioxidant, cytotoxic, and antimicrobial activities are among the most investigated activities, mainly in in vitro studies, with occasional in silico and in vivo studies. Clinical trials have not been conducted using depsides and tridepsides. Therefore, future research should focus on conducting more in vivo work and clinical trials, as well as on evaluating the other activities. Moreover, despite the significant increase in research work on the pharmacology of depsides and tridepsides, there are many of these compounds which have yet to be investigated (e.g., hiascic acid, lassalic acid, ovoic acid, crustinic acid, and hypothamnolic acid).

Phytochemical Analysis, Antioxidant, Antimicrobial, and Cytotoxic Activity of Different Extracts of Xanthoparmelia stenophylla Lichen from Stara Planina, Serbia

The aim of this study was to identify some of the secondary metabolites present in acetonic, methanolic, and hexanic extracts of lichen Xanthoparmelia stenophylla and to examine their antioxidant, antimicrobial, and cytotoxic activity. Compounds of the depsid structure of lecanoric acid, obtusic acid, and atranorin as well as usnic acid with a dibenzofuran structure were identified in the extracts by HPLC. The acetone extract was shown to have the highest total phenolic (167.03 ± 1.12 mg GAE/g) and total flavonoid content (178.84 ± 0.93 mg QE/g) as well as the best antioxidant activity (DPPH IC50 = 81.22 ± 0.54). However, the antimicrobial and antibiofilm tests showed the best activity of hexanic extract, especially against strains of B. cereus, B. subtilis, and S. aureus (MIC < 0.08, and 0.3125 mg/mL, respectively). Additionally, by using the MTT method, the acetonic extract was reported to exhibit a strong cytotoxic effect on the HeLa and HCT-116 cell lines, especially after 72 h (IC50 = 21.17 ± 1.85 and IC50 = 21.48 ± 3.55, respectively). The promising antioxidant, antimicrobial, and cytotoxic effects of Xanthoparmelia stenophylla extracts shown in the current study should be further investigated in vivo and under clinical conditions.

Genome and Metabolome MS-Based Mining of a Marine Strain of Aspergillus affinis

Aspergillus section Circumdati encompasses several species that express both beneficial (e.g., biochemical transformation of steroids and alkaloids, enzymes and metabolites) and harmful compounds (e.g., production of ochratoxin A (OTA)). Given their relevance, it is important to analyze the genetic and metabolic diversity of the species of this section. We sequenced the genome of Aspergillus affinis CMG 70, isolated from sea water, and compared it with the genomes of species from section Circumdati, including A. affinis's strain type. The A. affinis genome was characterized considering secondary metabolites biosynthetic gene clusters (BGCs), carbohydrate-active enzymes (CAZymes), and transporters. To uncover the biosynthetic potential of A. affinis CMG 70, an untargeted metabolomics (LC-MS/MS) approach was used. Cultivating the fungus in the presence and absence of sea salt showed that A. affinis CMG 70 metabolite profiles are salt dependent. Analyses of the methanolic crude extract revealed the presence of both unknown and well-known Aspergillus compounds, such as ochratoxin A, anti-viral (e.g., 3,5-Di-tert-butyl-4-hydroxybenzoic acid and epigallocatechin), anti-bacterial (e.g., 3-Hydroxybenzyl alcohol, l-pyroglutamic acid, lecanoric acid), antifungal (e.g., lpyroglutamic acid, 9,12,13-Trihydroxyoctadec-10-enoic acid, hydroxyferulic acid), and chemotherapeutic (e.g., daunomycinone, mitoxantrone) related metabolites. Comparative analysis of 17 genomes from 16 Aspergillus species revealed abundant CAZymes (568 per species), secondary metabolite BGCs (73 per species), and transporters (1359 per species). Some BGCs are highly conserved in this section (e.g., pyranonigrin E and UNII-YC2Q1O94PT (ACR toxin I)), while others are incomplete or completely lost among species (e.g., bikaverin and chaetoglobosins were found exclusively in series Sclerotiorum, while asperlactone seemed completely lost). The results of this study, including genome analysis and metabolome characterization, emphasize the molecular diversity of A. affinis CMG 70, as well as of other species in the section Circumdati.

In vitro evaluation of lysozyme activity and antimicrobial effect of extracts from four Tunisian lichens: Diploschistes ocellatus, Flavoparmelia caperata, Squamarina cartilaginea and Xanthoria parietina

Since lichens have been recognised as a potential natural source of bioactive substances, the aim of this study was to investigate the antimicrobial, lysozyme and antifungal effects of methanol, acetone and quencher extracts from four lichens: Diploschistes ocellatus, Flavoparmelia caperata, Squamarina cartilaginea and Xanthoria parietina. The results showed that the tested extracts had antimicrobial activity against Gram-positive and Gram-negative bacteria and anti-candida, and inhibit the spore germination of tested fungi. The different extracts varied in their effect as determined by the diameter of the inhibition zone, the highest values being observed with the methanol and acetone extracts (29.5 and 27.5 mm, respectively) for S. cartilaginea against Enterococcus faecalis. For powdered material (quencher), F. caperata showed the highest inhibition diameter (25.5 mm) against Staphylococcus aureus. The Minimum Inhibitory Concentration (MIC) values varied from 125 to 2000 μg mL^-1. Methanol extracts of S. cartilaginea were more active against Enterobacter cloacae (MIC 125 µg mL^-1) and Staphylococcus aureus (MIC 125 µg mL^-1), and also affected lysozyme activity against Staphylococcus aureus, as well as the morphology of fungal hyphae. This study demonstrated that the investigated species are a potential source of bioactive compounds which are potentially important antimicrobial agents.

Anti-cancer Evaluation of Depsides Isolated from Indonesian Folious Lichens: Physcia millegrana, Parmelia dilatata and Parmelia aurulenta

Cancer is a serious health burden on global societies. The discovery and development of new anti-cancer therapies remains a challenging objective. Although it has been shown that lichen secondary metabolites may be potent sources for new anti-cancer agents, the Indonesian- grown folious lichens, Physcia millegrana,Parmelia dilatata and Parmeila aurulenta, have not yet been explored. In this study exhaustive preparative high-performance liquid chromatography was employed to isolate the lichen constituents with spectroscopic and spectrometric protocols identifying nine depsides 9–17, including the new methyl 4-formyl-2,3-dihydroxy-6-methylbenzoate 13. The cytotoxicity of the depsides towards cancer cells was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results indicated lowest toxicity of the depsides towards human A549 lung cancer cells. Importantly, the di-depsides (11, 12 and 17) showed greatest toxicity, indicating that these structures are biologically more active than the mono-depsides against the HepG2 liver cancer, A549 lung cancer and HL-60 leukemia cell lines.