PLGA-PEG-COOH nanoparticles are efficient systems for delivery of mefloquine to Echinococcus multilocularis metacestodes.

Alveolar echinococcosis (AE) is a severe disease caused by the infection with the larval stage of Echinococcus multilocularis, the metacestode. As there is no actual curative drug therapy, recommendations to manage AE patients are based on radical surgery and prophylactic administration of albendazole or mebendazole during 2 years to prevent relapses. There is an urgent need for new therapeutic strategies for the management of AE, as the drugs in use are only parasitostatic, and can induce toxicity.

Lichen or Associated Micro-Organism Compounds Are Active against Human Coronaviruses.

(1) Background: Since the emergence of SARS-CoV-2, responsible for the COVID-19 pandemic, efforts have been made to identify antiviral compounds against human coronaviruses. With the aim of increasing the diversity of molecule scaffolds, 42 natural compounds, of which 28 were isolated from lichens and 14 from their associated microorganisms (bacteria and fungi), were screened against human coronavirus HCoV-229E. (2) Methods: Antiviral assays were performed using HCoV-229E in Huh-7 and Huh-7/TMPRSS2 cells and SARS-CoV-2 in a Vero-81-derived clone with a GFP reporter probe.

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.

Lichen butyrolactone derivatives disrupt oral bacterial membrane.

We have previously demonstrated that out of the butyrolactones series synthesized based on the natural lichen metabolite lichesterinic acid, compound (B-13) was the most effective against oral bacteria. However, its antibacterial mechanism is still unknown. In this study, we have investigated its bacterial localization by synthesizing a fluorescently labeled B-13 with NBD while maintaining its antibacterial activity.

Mycosporine-Like Amino Acids (MAAs) in Time-Series of Lichen Specimens from Natural History Collections.

Mycosporine-like amino acids (MAAs) were quantified in fresh and preserved material of the chlorolichen var. (Verrucariaceae/Ascomycota). The analyzed samples represented a time-series of over 150 years.

Tsavoenones A-C: unprecedented polyketides with a 1,7-dioxadispiro[4.0.4.4]tetradecane core from the lichen Parmotrema tsavoense.

New racemic dispiranic polyketides, tsavoenones A (1), B (2) and C (3), having a novel 1,7-dioxadispiro[4.0.4.

Antibacterial activities of natural lichen compounds against Streptococcus gordonii and Porphyromonas gingivalis.

The oral bacteria not only infect the mouth and reside there, but also travel through the blood and reach distant body organs. If left untreated, the dental biofilm that can cause destructive inflammation in the oral cavity may result in serious medical complications. In dental biofilm, Streptococcus gordonii, a primary oral colonizer, constitutes the platform on which late pathogenic colonizers like Porphyromonas gingivalis, the causative agent of periodontal diseases, will bind.

New erythritol derivatives from the fertile form of Roccella montagnei.

Chemical investigation of the methanol extract of the fertile form of Roccella montagnei collected in Vietnam afforded twelve secondary metabolites, including five new montagnetol derivatives, orsellinylmontagnetols A-D and a furanyl derivative together with seven known compounds. Their chemical structures were elucidated by analysis of 1D and 2D NMR and high resolution mass spectroscopic data. The relative stereochemistry of two chiral centers (C-2 and C-3) of orsellinylmontagnetols A and B was elucidated by comparison of their coupling constants and the specific rotation with those reported in the literature while the absolute stereochemistry was determined by the application of a modified Mosher method for the hydroxy group at C-3.

Design, synthesis and biological evaluation of potential antibacterial butyrolactones.

Novel butyrolactone analogues were designed and synthesized based on the known lichen antibacterial compounds, lichesterinic acids (B-10 and B-11), by substituting different functional groups on the butyrolactone ring trying to enhance its activity. All synthesized butyrolactone analogues were evaluated for their in vitro antibacterial activity against Streptococcus gordonii. Among the derivatives, B-12 and B-13 had the lowest MIC of 9.

Lichen-derived compounds show potential for central nervous system therapeutics.

Background: Natural products from lichens are widely investigated for their biological properties, yet their potential as central nervous system (CNS) therapeutic agents is less explored.

Purpose: The present study investigated the neuroactive properties of selected lichen compounds (atranorin, perlatolic acid, physodic acid and usnic acid), for their neurotrophic, neurogenic and acetylcholine esterase (AChE) activities.

Methods: Neurotrophic activity (neurite outgrowth) was determined using murine neuroblastoma Neuro2A cells.

UV-protectant metabolites from lichens and their symbiotic partners.

Lichens are structurally complex symbiotic organisms that are exposed to a wide variety of external conditions (extreme temperatures, desiccation, UV radiation, etc.). These poikilohydric organisms have developed various mechanisms of photoprotection, such as light scattering, radiation screening, thermal dissipation, activation of antioxidant defense and macromolecules and membrane repair.

Characterization and identification of mycosporines-like compounds in cyanolichens. Isolation of mycosporine hydroxyglutamicol from Nephroma laevigatum Ach.

Mycosporine-like compounds, comprising mycosporines and mycosporine-like amino acids (MAAs) are UV protecting secondary metabolites described in organisms such as fungi, algae, cyanobacteria or animals. Lichens however, were only poorly investigated for such constituents so far. Here, a method for the characterization of mycosporines and MAAs in purified aqueous extracts, involving HPTLC coupled to spectrophotodensitometry, HPLC-DAD-MS(n) and UPLC-HRMS analysis, is described.

A novel aryl-hydrazide from the marine lichen Lichina pygmaea: isolation, synthesis of derivatives, and cytotoxicity assays.

A new aryl-hydrazide l-glutamic acid derivative, pygmeine (3), was isolated from a methanolic extract of Lichina pygmaea, a marine lichen. Synthetic derivatives obtained via a two-step coupling of l-glutamic acid with phenylhydrazine moieties were useful to elucidate the structure of 3 and to carry out biological assays. Thus, the cytotoxicity of the ortho-, meta-, and para-hydroxyl isomers along with their respective benzyl intermediates, and a natural methoxylated analog, were evaluated on murine and human melanoma cells (B16, A375).

Multiple dual-mode centrifugal partition chromatography as an efficient method for the purification of a mycosporine from a crude methanolic extract of Lichina pygmaea.

Centrifugal partition chromatography method was applied to the separation and purification of a crude methanolic extract of a cyanobacterial lichen, Lichina pygmaea. A multiple dual-mode was used to separate two compounds of interest, namely mycosporine-serinol and a glutamic acid derivative. These compounds are described here for the first time in a lichen.

Preparation and characterization of copper(II) and nickel(II) complexes of a new chiral salen ligand derived from (+)-usnic acid.

Chiral copper(II) and nickel(II) complexes were obtained after reaction of diacetate salts with a new chiral salen ligand derived from (+)-usnic acid.