Search

The rise of antibiotic-resistant bacterial strains represents an important challenge for global health, underscoring the critical need for innovative strategies to confront this threat. Natural products and their derivatives have emerged as a promising reservoir for drug discovery. The social amoeba Dictyostelium discoideum is a potent model organism in this effort. Employing this invertebrate model, we introduce a novel perspective to investigate natural plant extracts in search of molecules with potential antivirulence activity. Our work established an easy-scalable developmental assay targeting a virulent strain of Klebsiella pneumoniae , with Helenium aromaticum as the representative plant. The main objective was to identify tentative compounds from the Helenium aromaticum extract that attenuate the virulence of K. pneumoniae virulence without inducing cytotoxic effects on amoeba cells. Notably, the methanolic root extract of H. aromaticum fulfilled these prerequisites compared to the dichloromethane extract. Using UHPLC Q/Orbitrap/ESI/MS/MS, 63 compounds were tentatively identified in both extracts, 47 in the methanolic and 29 in the dichloromethane, with 13 compounds in common. This research underscores the potential of employing D. discoideum -assisted pharmacognosy to discover new antivirulence agents against multidrug-resistant pathogens.

In this study, isolation and purification of lichen substances from Usnea cornuta were performed using conventional solvents, green solvents and green technologies. In addition, several lichen compounds were tentatively identified by UHPLC/ESI/MS/MS and usnic acid, diffractaic and galbinic acids were quantified as well. Limonene, ethyl lactate and methanol, were compared regarding their extraction properties and antioxidant capacities, determined by DPPH, ORAC, and FRAP assays. In the ethyl lactate, methanol and limonene extracts, 28 compounds in all, were detected for the first time by high resolution UHPLC-MS/MS fingerprinting. Untargeted metabolomics tentatively identified 14 compounds from the methanolic extract, 4 from limonene extract, and 20 metabolites from ethyl lactate extract. The green extract of ethyl lactate showed a similar antioxidant capacity to toxic methanol extract, except at ORAC assay where it was higher. Therefore, ethyl lactate can replace methanol, to provide more sustainable green chemistry methods.

For the first time, we report a green extraction of lichen substances assisted by high power ultrasounds from Hypotrachyna cirrhata using ethyl lactate. This sustainable alternative was comparable, both in isolation and detection of lichen substances, to methanol. In the metabolomic analysis, a total of 77 lichen substances were detected comprising depsides, depsidones, dibenzofurans, organic acids, and lipids. Although the UHPLC/ESI/MS profiles were similar, the antioxidant activity was higher for the ethyl lactate extract. Ethyl lactate can replace toxic organic solvents, such as methanol, in order to provide more sustainable green chemistry methods.

UHPLC/ESI/MS/MS profiling followed by bioactivity guided isolation of Pseudevernia furfuracea ( P. furfuracea ) extract yielded two polyphenolic molecules, Methyl haematommate (PF-1) and Atraric acid (PF-2). These molecules were evaluated for bioactivity against five cancerous cell lines. The results revealed that atraric acid showed significant activity against ovarian cancer cell line (PA-1) having GI 50 at 16.42 µg/mL and moderate activity against the breast cancer cell line (MCF-7), having GI 50 at 64.35 µg/mL. The results were further supported by in silico molecular docking studies of atraric acid with the epidermal growth factor receptor (EGFR) tyrosine kinase protein. The study revealed that atraric acid has the capacity to act as a potential EGFR inhibitor via occupying the ATP binding pocket of EGFR and making favourable electrostatic interactions and van der Waals interaction with its key residues. Our results highlight P. furfuracea and its polyphenolic compound, atraric acid as a promising candidate for ovarian cancer management.

Alzheimer´s disease (AD) is the most common form of dementia involving Aβ and tau protein. So far, AD cure remains elusive, but considering that AD progresses throughout tau pathology, which turns tau protein an appropriate target, besides tau is also included in other neurodegenerative disorders named as tauopathies. Here, we have isolated seventeen compounds belonging to six lichens species. Due to scarce of spectroscopic data of the compound 5,7-dihydroxy-6-methylphthalide, we explained their structural elucidation based on NMR data. In this study, we show that only tenuiorin from Umbilicaria antarctica inhibited 50% of tau 4R at 100 µM. Then, we shown that molecular interactions of tenuiorin with the steric zipper model of the hexapeptide 306 VQIVYK 311 were studied by docking calculations and the results suggested that tenuiorin forms both hydrogen bonds with lysine and glutamine side chains and forms several hydrophobic interactions with valine and lysine from 306 VQIVYK 311 motif.