Recent advances on Pestalotiopsis genus: chemistry, biological activities, structure-activity relationship, and biosynthesis

DMSO enhances the biosynthesis of epoxyquinols in Pestalotiopsis sp. (strain IQ-011) and yields new [4 + 2] cycloaddition dimers

Pestalotiopsis sp. (strain IQ-011) produces cuautepestalorin (10), a 7,8-dihydrochromene-oxoisochromane adduct featuring a spiro-polycyclic (6/6/6/6/6/6) ring system. Additionally, it yields its proposed biosynthetic precursors: cytosporin M (1) and oxopestalochromane (11) when cultured under standard conditions (fermentation in solid media). Following an OSMAC approach guided by metabolomic studies (PCA and molecular networks), it was established that the epigenetic modulator DMSO dramatically increases the production of 1 up to 50 times according to feature-based molecular networking (FBMN) analysis, and triggers the production of other derivatives from the epoxyquinol family. Chemo-targeted isolation resulted in the discovery of four new compounds: 19-hydroxycytosporin M (2) and three [4 + 2] cycloaddition products: ent-eutyscoparol J (4), ent-pestaloquinol A (6) and ent-pestaloquinol B (8). The structures of all isolates were established based on spectroscopic, spectrometric, chiroptical, and X-ray diffraction analyses. This study demonstrates the potential of combining metabolomic tools with DMSO as an epigenetic modulator to enhance fungal metabolite diversity and highlights the importance of chiroptical methods for accurate compound identification.

Isolation and biological activity of six new polyketide and terpenoid derivatives from Neopestalotiopsis Clavispora AL01

A fungus strain, Neopestalotiopsis clavispora AL01, was isolated from the leaf spot of the plant Phoenix dactylifera. Further chemical investigation of the fermentation extract of this strain afforded six new secondary metabolites (1-6), along with 11 known compounds (7-17) which included a new natural compound (7). Their structures were determined by extensive spectroscopic analysis including one-and two-dimensional (1D and 2D) NMR spectroscopy, high-resolution electrospray ionization mass spectrometry (HRESIMS), and ECD and NMR calculations. All compounds were evaluated for their phytotoxic activities. Among them, compounds 10, 12 and 13 exhibited phytotoxic activities against Nicotiana tabacum. Compound 3 exhibited weak antibacterial activity against methicillin-resistant Staphylococcus aureus, Micrococcus luteus and Vibrio harveyi. Taken collectively, these findings establish a solid research foundation for future investigations on bioactive natural products derived from phytopathogenic fungi.

Pestalotiopols E-J, Six New Polyketide Derivatives from a Marine Derived Fungus Pestalotiopsis sp. SWMU-WZ04-1

Chemical epigenetic cultivation of the sponge-derived fungus Pestalotiopsis sp. SWMU-WZ04-1 contributed to the identification of twelve polyketide derivatives, including six new pestalotiopols E-J (1-6) and six known analogues (7-12). Their gross structures were deduced from 1D/2D NMR and HRESIMS spectroscopic data, and their absolute configurations were further established by circular dichroism (CD) Cotton effects and the modified Mosher's method. In the bioassay, the cytotoxic and antibacterial activities of all compounds were evaluated. Chlorinated benzophenone derivatives 7 and 8 exhibited inhibitory effects on Staphylococcus aureus and Bacillus subtilis, with MIC values varying from 3.0 to 50 μg/mL. In addition, these two compounds were cytotoxic to four types of human cancer cells, with IC50 values of 16.2~83.6 μM. The result showed that compound 7 had the probability of being developed into a lead drug with antibacterial ability.