Polyketide-Derived Secondary Metabolites from a Dothideomycetes Fungus, Pseudopalawania siamensis gen. et sp. nov., (Muyocopronales) with Antimicrobial and Cytotoxic Activities

Abstract

Pseudopalawania siamensis gen. et sp. nov., from northern Thailand, is introduced based on multi-gene analyses and morphological comparison. An isolate was fermented in yeast malt culture broth and explored for its secondary metabolite production. Chromatographic purification of the crude ethyl acetate (broth) extract yielded four tetrahydroxanthones comprised of a new heterodimeric bistetrahydroxanthone, pseudopalawanone (1), two known dimeric derivatives, 4,4′-secalonic acid D (2) and penicillixanthone A (3), the corresponding monomeric tetrahydroxanthone paecilin B (4), and the known benzophenone, cephalanone F (5). Compounds 1–3 showed potent inhibitory activity against Gram-positive bacteria. Compounds 2 and 3 were inhibitory against Bacillus subtilis with minimum inhibitory concentrations (MIC) of 1.0 and 4.2 μg/mL, respectively. Only compound 2 showed activity against Mycobacterium smegmatis. In addition, the dimeric compounds 1–3 also showed moderate cytotoxic effects on HeLa and mouse fibroblast cell lines, which makes them less attractive as candidates for development of selectively acting antibiotics.

Virtual screening-driven drug discovery of SARS-CoV2 enzyme inhibitors targeting viral attachment, replication, post-translational modification and host immunity evasion infection mechanisms

“…Secondary metabolites from fungi have been successfully developed into several drug medications that include, but not limited to, antineoplastics, antibiotics, and antivirals (Zaiyou et al, 2017). Due to the immense range of habitats that fungi inhabit and their need to compete against a diverse array of organisms, fungal organisms have developed numerous ways to survive (Hyde et al, 2019) and offers great potential as tomorrows bioresource for the discovery of biologically active natural products (Kuephadungphan et al, 2019;Mapook et al, 2020;Notarte et al, 2017Notarte et al, , 2018Notarte et al, , 2019Phukhamsakda et al, 2018).…”

Chromanone Lactones: A Neglected Group of Natural Products – Isolation, Structure Elucidation, Bioactivity, and Synthesis

“…The last compound of the mixed chromanone lactone dimer group isolated up to now is pseudopalawanone ( 228 ) (Figure 22) obtained from the fungus Pseudopalawania siamensis gen. et sp. nov [24] . Again, the structure of this compound was elucidated through standard procedures, revealing an exceptionally oxygenated tetrahydroxanthone and a CL unit with a 2‐8’ connection.…”

“…The last compound of the mixed chromanone lactone dimer group isolated up to now is pseudopalawanone (228) (Figure 22) obtained from the fungus Pseudopalawania siamensis gen. et sp. nov. [24] Again, the structure of this compound was elucidated through standard procedures, revealing an exceptionally oxygenated tetrahydroxanthone and a CL unit with a 2-8' connection. The relative configuration of the compound was finally established utilizing coupling constant analysis, 2D-NMR and NOE experiments together with CD analysis, and was determined as (aS,5S*,6S*,8S*,10aS*,2'S*,9'R*,10'R*).…”

Not One, But Five: Virtual Screening-Driven Drug Discovery of SARS-CoV2 Enzyme Inhibitors Targeting Viral Attachment, Replication and Post-Translational Infection Mechanisms

“…They can be grown with relative ease and have many characteristics that offer great promise for application in medicine. Efforts along this area have been highlighted in several fungal genera that produce secondary metabolites displaying a wide range of biological activities [44][45][46][47][48][49][50].…”