Can lichen secondary compounds impact upon the pathogenic soil fungi Fusarium oxysporum and F. avenaceum?

The antifungal activity of secondary lichen metabolites extracted by means of acetone and ethanol from Cetraria islandica, Cladonia mitis, C. rangiferina, Pseudevernia furfuracea and Usnea dasopoga on the pathogenic fungi Fusarium oxysporum and F. avenacuem was examined. The activity of extracted compounds was tested after their mixture with PDA medium before solidification. The most active extracts inhibiting the growth of fungal mycelia contained fumarprotocetraric, salazinic and usnic acids, and atranorin. Unparalleled activity was demonstrated by an ethanol extract from mixed C. islandica and P. furfuracea thalli, which accelerated the growth of F. avenaceum compared with the control test with ethanol. The growth rate of the two Fusarium representatives was strongly inhibited by both alcoholic extracts from C. mitis and from C. rangiferina, more strongly than by the extracts from the mixed thalli of the two terricolous taxa. A dose of 1 ml of acetone added to the medium had no significant effect on the growth of the tested fungi; it indicates usefulness of acetone as a solvent for some lichen compounds in this type of experiment.

Beneficial Effects of Liposomal Formulations of Lichen Substances: A Review

: Lichens are commonly used as essential traditional medicines to treat various conditions, including skin disorders, wounds, digestive, respiratory, obstetric, and gynecological problems in many cultures in Africa, Asia, Europe, Haitian, Oceania, and North and South America. Lichens have been deeply investigated for their phytochemical properties, and to date, numerous compounds (also known as substances) have been successfully isolated from the extracts. However, the low solubility and bioavailability of pure lichen substances have been widely recognized as the significant issues hindering their biological applications. Recently, several groups have investigated the properties and the potential applications of lichen metabolites-based liposomal formulations and revealed a substantial improvement in their solubility, bioactivity, and toxicity in the animal. Thus, in this topical review, we aimed to provide an overview of liposomal structures, the efficacy of liposomal formulations, as well as their beneficial effects as compared to the free compounds themselves.

A Review of Anti-Cancer and Related Properties of Lichen-Extracts and Metabolites

Background: Lichens are a composite consortium of fungus and alga. The symbiotic organisms are naturally equipped with distinct characteristics as compared to constituting organisms separately. Lichens due to their peculiar anatomy and physiology, are the reservoir of more than 600 unique secondary metabolites, also known as ‘lichen substances’. Since ancient times, many ethnic groups from various parts of the world had knowledge about the applications of lichens as major provenance of food/fodder, medicine, dyes, spices, perfumes, etc. Lichen substances have shown impressive antioxidant, antimicrobial, antiviral, antitumor, and anti-inflammatory activities under experimental conditions. Usnic acid, a well-known metabolite, found in several species of lichens, possesses potent antioxidant and anti-inflammatory activities. It also has significant anti-proliferative potential as revealed through testing in different cancer cell lines. Atranorin, Lecanoric acid, Norstictic acid, Lobaric acid, Stictic acid, Ramalin, Gyrophoric acid, Salazinic acid, Protolichesterinic, and Fumarprotocetraric acid are some of the other purified lichen metabolites with potent anti-cancer activities. Objective: This study presents an overview of lichen derived extracts/compounds augmenting the anti-cancer (related) properties. Method: The review comprehends different studies (in vivo and in vitro) backing up the possibility of lichen extracts and metabolites towards their use as antioxidant, anti-proliferative, anti-inflammatory and EMT-inhibiting agents. Results: The review focuses on anti-cancer and related properties of lichen extracts and metabolites that include their anti-oxidative, anti-inflammatory, anti-proliferative and pro-apoptotic, cancer stemness reduction, activities and, the potential of inhibition of cancer-associated Epithelial-mesenchymal transition (EMT) that is responsible for multiple drug-resistance and metastasis of cancer cells in a large proportion of cases. Conclusion: Lichens can be the repertoire of a plethora of lichen metabolites with putative bioactive potential, which is needed to be explored in order to find out novel anti-cancer drugs.

Anticancer Potential of Lichens’ Secondary Metabolites

Lichens produce different classes of phenolic compounds, including anthraquinones, xanthones, dibenzofuranes, depsides and depsidones. Many of them have revealed effective biological activities such as antioxidant, antiviral, antibiotics, antifungal, and anticancer. Although no clinical study has been conducted yet, there are number of in vitro and in vivo studies demonstrating anticancer effects of lichen metabolites. The main goal of our work was to review most recent published papers dealing with anticancer activities of secondary metabolites of lichens and point out to their perspective clinical use in cancer management.

Two new Micarea species (Pilocarpaceae) from Western Europe

Two new Micarea species, M. minuta and M. pseudotsugae, are described from the Netherlands based on morphological, chemical and molecular data. Micarea minuta belongs to the M. denigrata group and can be distinguished from other similar species of this group by its small apothecia, Sedifolia-grey pigment in the epihymenium, mostly 1-septate and small ascospores, 40–80 μm wide mesopycnidia, and the lack of secondary lichen metabolites detectable by thin-layer chromatography. Micarea pseudotsugae is a member of the M. prasina group and is characterized by an areolate, granular to subsquamulose thallus, the presence of methoxymicareic acid, the lack of Sedifolia-grey pigment, the presence of crystals (visible in polarized light) in the apothecia only, and one type of conidia (mesoconidia). The phylogenetic position of the newly described species was studied based on mtSSU rDNA marker analysis; M. minuta was found to be closely related to M. denigrata, M. nitschkeana and M. subnigrata, while M. pseudotsugae was found to be closely related to M. byssacea and M. laeta. Notes on secondary chemistry, ecology, distribution and phylogeny are given.

Morphology and secondary chemistry in species recognition of Parmelia omphalodes group – evidence from molecular data with notes on the ecological niche modelling and genetic variability of photobionts

To evaluate the importance of morphological and chemical characters used in the recognition of species within the Parmelia omphalodes group, we performed phylogenetic, morphological and chemical analyses of 335 specimens, of which 34 were used for molecular analyses. Phylogenetic analyses, based on ITS rDNA sequences, show that P. pinnatifida is distinct from P. omphalodes and the most important difference between those species is the development of pseudocyphellae. In P. pinnatifida, they are mostly marginal and form white rims along lobes margins, but laminal pseudocyphellae can develop in older parts of thalli and are predominantly connected with marginal pseudocyphellae. In contrast, in P. omphalodes laminal pseudocyphellae are common and are predominantly not connected to marginal pseudocyphellae. Chemical composition of secondary lichen metabolites in both analysed species is identical and therefore this feature is not diagnostic in species recognition. Few samples of P. discordans, species morphologically similar to P. omphalodes and P. pinnatifida, were also included in the analyses and they are nested within the clade of P. omphalodes, despite the different chemistry (protocetraric acid present versus salazinic acid in P. omphalodes). All taxa of the P. omphalodes group occupy similar niches, but their potential distributions are wider than those currently known. The absence of specimens in some localities may be limited by the photobiont availability. Parmelia omphalodes and P. pinnatifida are moderately selective in photobiont choice as they form associations with at least two or three lineages of Trebouxia clade S. Parmelia pinnatifida, as well as P. discordans are associated with Trebouxia OTU S02 which seems to have a broad ecological amplitude. Other lineages of Trebouxia seem to be rarer, especially Trebouxia sp. OTU S04, which is sometimes present in P. pinnatifida. This study indicates the importance of extensive research including morphology, chemistry and analysis of molecular markers of both bionts in taxonomical studies of lichens.

A database of high-resolution MS/MS spectra for lichen metabolites

While analytical techniques in natural products research massively shifted to liquid chromatography-mass spectrometry, lichen chemistry remains reliant on limited analytical methods, Thin Layer Chromatography being the gold standard. To meet the modern standards of metabolomics within lichenochemistry, we announce the publication of an open access MS/MS library with 250 metabolites, coined LDB for Lichen DataBase, providing a comprehensive coverage of lichen chemodiversity. These were donated by the Berlin Garden and Botanical Museum from the collection of Siegfried Huneck to be analyzed by LC-MS/MS. Spectra at individual collision energies were submitted to MetaboLights (https://www.ebi.ac.uk/metabolights/MTBLS999) while merged spectra were uploaded to the GNPS platform (CCMSLIB00004751209 to CCMSLIB00004751517). Technical validation was achieved by dereplicating three lichen extracts using a Molecular Networking approach, revealing the detection of eleven unique molecules that would have been missed without LDB implementation to the GNPS. From a chemist’s viewpoint, this database should help streamlining the isolation of formerly unreported metabolites. From a taxonomist perspective, the LDB offers a versatile tool for the chemical profiling of newly reported species.

Một hợp chất đơn vòng mới từ loài địa y Parmotrema tsavoense (Krog & Swinscow) Krog & Swinscow (Parmeliaceae)

A new monoaromatic compound, methyl (E)-2,4-dihydroxy-6-methyl-3-(3-oxobut-1-en-1-yl)benzoate (1), together with two common lichen metabolites atranol (2), 2-O-methylatranol (3) were isolated from the lichen Parmotrema tsavoense (Krog & Swinscow) Krog & Swinscow. Their chemical structures were established by 1D NMR, 2D NMR, high resolution ESI–MS spectroscopic analysis and comparison with those reported in the literatures.