Cladamide: a new ceramide from the endophytic fungus Cladosporium cladosporioides

New sesquiterpene from a soil fungus of Trichoderma sp

Sixteen secondary metabolites, including one new sesquiterpene (1, named isocyclonerodiol oxide), seven known sesquiterpenes (2-8), two sorbicillinoid polyketides (15, 16), and six known other compounds (9-14) were isolated from the fermentation broth of Trichoderma sp. T-4-1. The structure of 1 was determined by 1 D, 2 D NMR (HMBC, HSQC, 1H-1H COSY, NOESY), and HRESIMS spectra. In addition, sesquiterpenes and sorbicillinoid polyketides showed significant antiviral activities.

Calmodulin-Targeting Molecules from Ageratina grandifolia

Four new natural chemical entities, including 2-hydroxy-α-truxillic acid (2), (3R,4S)-2,2-dimethyl-3-hydroxy-4-(1-angeloyloxy)-6-acetyl-7-methoxychromane (3), N-tricosanoyltyramine (4), and grandifolamide (5), were isolated along with 11 known compounds (1, 6-15) from the aerial parts of Ageratina grandifolia. The chemical structures were elucidated using chemical derivatization and HR-MS, NMR, and DFT-calculated chemical shifts, combined with DP4+ statistical analysis. It was found that 2 decomposed into its biogenetic precursor, o-coumaric acid, upon standing at room temperature for a few weeks. 3,5-Diprenyl-4-hydroxyacetophenone (8), O-methylencecalinol (10), encecalin (11), and encecalinol (12) bound to calmodulin (CaM) with higher affinity than chlorpromazine, a well-known CaM inhibitor. Molecular dynamics studies revealed that the complexes of these compounds with CaM remained stable during the simulation. Altogether these results revealed the therapeutic and research tool potential of compounds 8, 10, 11, and 12.

Versisterol, a new endophytic steroid with 3CL protease inhibitory activity from Avicennia marina (Forssk.) Vierh

A new epoxy ergostane sterol, named versisterol, was isolated from Aspergillus versicolor, an endophytic fungus from Avicennia marina. The structure of the isolated compound was deduced by means of one- and two-dimensional NMR and high-resolution mass spectrometry. The absolute stereochemistry was elucidated by NOESY analysis, and experimental and calculated time-dependent density functional theory (TD-DFT) circular dichroism spectroscopy. Versisterol inhibited 3CL protease (3CL^pro) with an IC₅₀ value of 2.168 ± 0.09 μM. Binding affinities and molecular interactions of versisterol towards 3CL^pro were scrutinized and compared to lopinavir with the help of the combination of docking computations and molecular dynamics (MD) simulation. In silico calculations demonstrated a comparable binding affinity of versisterol with a docking score of -9.4 kcal mol^-1, and MM-GBSA binding energy over 200 ns MD simulation of -29.1 kcal mol^-1, with respect to lopinavir (-9.8 and -32.2 kcal mol^-1, respectively). These findings suggested that versisterol can be an auspicious prototype for developing new 3CL^pro drug candidates against COVID-19.