CASE-DFT Structure Elucidation of Proton-Deficient Chlorodepsidones from the Indonesian Lichen and Structure Revision of Flavicansone.

Biodiscovery efforts in Indonesia have aimed to explore the understudied chemical diversity of its rich lichen flora, seeking to find new products endowed with significant biological properties. The chemical screening of a extract led to selection of this species for further investigation. LC/MS and H NMR-based dereplication pinpointed six chlorodepsidones from the thallus of a sample of this lichen.

Synthesis of galactomannan fragments to help NMR assignment of polysaccharides extracted from lichens.

The synthesis of six model trisaccharides representative of galactomannans produced by lichens was performed through stereoselective glycosylation. These standards include linear and branched galactomannans bearing either galactofuranosyl or galactopyranosyl entities. The complete assignment of H and C signals for both forms of synthetically reduced oligosaccharides was performed.

Salazinic Acid and Norlobaridone from the Lichen : Antioxidant Activity, α-Glucosidase Inhibitory and Molecular Docking Studies.

The present study was intended for the identification of secondary metabolites in acetone extract of the lichen using UPLC-ESI-QToF-MS/MS and the detection of bioactive compounds. This study led to the identification of 22 metabolites based on their MS/MS spectra, accurate molecular masses, molecular formula from a comparison of the literature database (DNP), and fragmentation patterns. In addition, potent antioxidant and α-glucosidase inhibitory potentials of acetone extract of motivated us to isolate 10 metabolites, which were characterized as salazinic acid (), norlobaridone (), atranorin (), lecanoric acid (), lichesterinic acid (), protolichesterinic acid (), methyl hematommate (), iso-rhizonic acid (), atranol (), and methylatratate ( based on their spectral data.

Comprehensive Lichenometabolomic Exploration of Vain Using UPLC-Q-ToF-MS/MS: An Identification of Free Radical Scavenging and Anti-Hyperglycemic Constituents.

In this study, we propose ultra-performance liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (UPLC-QToF-MS/MS)-guided metabolite isolation as a choice analytical approach to the ongoing structure−activity investigations of chemical isolates from the edible lichen, Ramalina conduplicans Vain. This strategy led to the isolation and identification of a new depside (5) along with 13 known compounds (1−4, 6−14), most of which being newly described in this lichen species. The structures of the isolates were established by detailed analysis of their spectral data (IR, NMR, and Mass).

Chemical fingerprinting of the Brazilian medicinal plant (R. Br.) Less. (Asteraceae) collected at different altitudes.

(R. Br.) Less.

Synthesis of an Exhaustive Library of Naturally Occurring Gal-Man and Gal-Man Disaccharides. Toward Fingerprinting According to Ring Size by Advanced Mass Spectrometry-Based IM-MS and IRMPD.

Nature offers a huge diversity of glycosidic derivatives. Among numerous structural modulations, the nature of the ring size of hexosides may induce significant differences on both biological and physicochemical properties of the glycoconjugate of interest. On this assumption, we expect that small disaccharides bearing either a furanosyl entity or a pyranosyl residue would give a specific signature, even in the gas phase.

Which Specialized Metabolites Does the Native Subantarctic Gastropod Notodiscus hookeri Extract from the Consumption of the Lichens Usnea taylorii and Pseudocyphellaria crocata?

is the only representative of terrestrial gastropods on Possession Island and exclusively feeds on lichens. The known toxicity of various lichen metabolites to plant-eating invertebrates led us to propose that evolved means to protect itself from their adverse effects. To validate this assumption, the current study focused on the consumption of two lichen species: and .

NMR reassignment of stictic acid isolated from a Sumatran lichen Stereocaulon montagneanum (Stereocaulaceae) with superoxide anion scavenging activities.

The phytochemical study of Stereocaulon montagneanum harvested in Sumatra (Indonesia) led to the isolation of 11 known compounds including two metabolites not previously described in the genus Stereocaulon, peristictic acid (8) and menegazziaic acid (10). The complete 1H and 13C NMR spectral assignments of stictic acid derivatives are reported with some revisions. Five depsidones belonging to the stictic acid chemosyndrome were superoxide anion scavengers as potent as ascorbic acid and with no toxicity on two human cell lines.

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.

Death related to consumption of Rauvolfia sp. powder mislabeled as Tabernanthe iboga.

Powdered roots of iboga (Tabernanthe iboga) contain ibogaine, an alkaloid that has been used to treat addictions. We report the case of a 30-year-old woman who died after ingesting a powder labeled as Tabernanthe iboga she had bought online. Analysis of the powder revealed the absence of ibogaine but the presence of toxic alkaloids (ajmaline, yohimbine and reserpine) found in Rauvolfia sp.

Preliminary Studies on the Activity of Mixed Polyphenol-Heterocyclic Systems Against B16-F10 Melanoma Cancer Cells.

The Bcl-2 family includes 26 proteins involved in apoptosis. Cancer cells can develop the ability to avoid apoptosis through the upregulation and/or down regulation of such proteins Bax, Bcl-xL or Mcl-1, especially during chemoresistance progress. These proteins engaged in a network of dynamic interactions that control apoptosis triggering have become attractive therapeutic targets in cancers including melanoma.

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).