Potential of coumarins against Covid-19.

Antileishmanial bioassay guided fractionation of Geosmithia langdonii has resulted in the isolation and identification of two new compounds (1 and 2) together with 10 known compounds (3–12). The structures of the isolated metabolites were elucidated based on comprehensive 1D and 2D NMR spectroscopic data as well as mass spectrometry. The absolute configuration at C4, C5, and C6 of 2 was determined as R using a modified Mosher esterification method and NOESY correlations. The extracts and the isolated metabolites were evaluated for their antileishmanial activities. Compounds 3, 9, 11, and 12 were found to be active against Leishmania donovani with IC50 values of 6.9, 3.3, 8.5, and 9.2 μM, respectively, while compounds 1, 5, and 10 showed lower activities against L. donovani with IC50 values of 13.0, 47.3, and 34.0 μM, respectively.

A phytochemical study of Geosmithia lavendula Pitt led to the isolation of three new anthraquinones: 1-acetyl-2,4,6,8-tetrahydroxy-9,10-anthraquinone (1), 2-acetyl-1,4,5,7-tetrahydroxy-9,10-anthraquinone (2), and 1-acetyl-2,4,5,6,7-pentahydroxy-9,10-anthraquinone (3), as well as another new compound named didodecyl thiodipropionate (propionic acid, 3,3-sulfinyl di-1,1′-didodecyl ester) (4), along with ten known compounds: 1-acetyl-2,4,5,7-tetrahydroxy-9,10-anthraquinone (rhodolamprometrin) (5), 1-acetyl-2,4,5,7,8-pentahydroxy-9,10-anthraquinone (6), (22E)-ergosta-6,22-diene-3β,5α,8α-triol, p-hydroxybenzyl alcohol, oleic acid, D-mannitol, palmitic acid, stearic acid, cis-vaccenic acid and 2-decenal. The structures of the isolated metabolites were elucidated based on NMR spectroscopic and mass spectrometric data. Compound 1 exhibited moderate activity against methicillin resistant Staphylococcus aureus with an IC50 value of 16.1 μg/mL.

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