Identification of Antimicrobial Metabolites from the Egyptian Soil-Derived Amycolatopsis keratiniphila Revealed by Untargeted Metabolomics and Molecular Docking.

Actinomycetes are prolific producers of bioactive secondary metabolites. The prevalence of multidrug-resistant (MDR) pathogens has prompted us to search for potential natural antimicrobial agents. Herein, we report the isolation of rare actinobacteria from Egyptian soil. The strain was identified as Amycolatopsis keratiniphila DPA04 using 16S rRNA gene sequencing. Cultivation profiling, followed by chemical and antimicrobial evaluation of crude extracts, revealed the activity of DPA04 ISP-2 and M1 culture extracts against Gram-positive bacteria. Minimum inhibitory concentrations (MIC) values ranged from 19.5 to 39 µg/mL. Chemical analysis of the crude extracts using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF) led to the identification of 45 metabolites of different chemical classes. In addition, ECO-0501 was identified in the cultures with significant antimicrobial activity. Multidrug resistance in Staphylococcus aureus is reported to be related to the multidrug efflux pump (MATE). ECO-0501 and its related metabolites were subjected to molecular docking studies against the MATE receptor as a proposed mechanism of action. ECO-0501 and its derivatives (AK_1 and N-demethyl ECO-0501) had better binding scores (-12.93, -12.24, and -11.92 kcal/mol) than the co-crystallized 4HY inhibitor (-8.99 kcal/mol) making them promising candidates as MATE inhibitors. Finally, our work established that natural products from this strain could be useful therapeutic tools for controlling infectious diseases.

Cholinesterase Inhibitors from an Endophytic Fungus Aspergillus niveus Fv-er401: Metabolomics, Isolation and Molecular Docking.

Alzheimer's disease poses a global health concern with unmet demand requiring creative approaches to discover new medications. In this study, we investigated the chemical composition and the anticholinesterase activity of Aspergillus niveus Fv-er401 isolated from Foeniculum vulgare (Apiaceae) roots. Fifty-eight metabolites were identified using UHPLC-MS/MS analysis of the crude extract. The fungal extract showed acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory effects with IC50 53.44 ± 1.57 and 48.46 ± 0.41 µg/mL, respectively. Two known metabolites were isolated, terrequinone A and citrinin, showing moderate AChE and BuChE inhibitory activity using the Ellman's method (IC50 = 11.10 ± 0.38 µg/mL and 5.06 ± 0.15 µg/mL, respectively for AChE, and IC50 15.63 ± 1.27 µg/mL and 8.02 ± 0.08 µg/mL, respectively for BuChE). As evidenced by molecular docking, the isolated compounds and other structurally related metabolites identified by molecular networking had the required structural features for AChE and BuChE inhibition. Where varioxiranol G (-9.76 and -10.36 kcal/mol), penicitrinol B (-9.50 and -8.02 kcal/mol), dicitrinol A (-8.53 and -7.98 kcal/mol) and asterriquinone CT5 (-8.02 and -8.25 kcal/mol) showed better binding scores as AChE and BuChE inhibitors than the co-crystallized inhibitor (between -7.89 and 7.82 kcal/mol) making them promising candidates for the development of new drugs to treat Alzheimer's.

Anticholinesterase activity and metabolite profiling of Syagrus romanzoffiana (Cham.) Glassman leaves and fruits via UPLC-QTOF-PDA-MS.

The purpose of this study is to provide a complete metabolic profile of the hydroalcoholic extracts of the leaves and fruits of Syagrus romanzoffiana (Cham.) Glassman via UPLC-QTOF-PDA-MS and to evaluate their anticholinesterase activities in a model of Alzheimer disease. The current study has identified 39 metabolites belonging to various chemical classes (i.e. flavonols, phenolic acids, fatty acids, stilbenoids and lignans). While the fatty acids predominated in both leaves and fruits, the stilbenoids were more predominant in leaves. Their neuroprotective effect was comparable to Aricept; the standard drug used in treatment of Alzheimer disease. Both extracts significantly decreased the acetylcholinesterase activity and improved the histopathological changes in the cerebral cortex and cerebellum of rat model of aluminium chloride-induced Alzheimer disease. In light of the current study, Syagrus romanzoffiana (Cham.) Glassman is recommended as promising candidate for palliative treatment in Alzheimer disease through inhibition of the acetylcholinesterase activity.