Talarostatin, a vermistatin derivative from the soil-derived fungus Talaromyces thailandensis PSU-SPSF059.

The soil-derived fungus Talaromyces thailandensis PSU-SPSF059 produced one new vermistatin derivative, talarostatin, and seven known compounds including two vermistatins, two chrodrimanins, two diphenyl ethers and one penicillide derivative. Extensive spectroscopic analysis was performed to identify their structures. The absolute configuration of talarostatin was determined by comparing the experimental and calculated electronic circular dichroism data. The antimicrobial and cytotoxic activities of the isolated secondary metabolites were also evaluated.

A nonadride derivative from the marine-derived fungus Aspergillus chevalieri PSU-AMF79.

One new nonadride enantiomer, ent-epiheveadride, along with five known dioxopiperazine derivatives were isolated from the marine-derived fungus Aspergillus chevalieri PSU-AMF79. Their structures were identified by extensive spectroscopic analysis. The absolute configuration of ent-epiheveadride was determined by comparison of the specific rotation and electronic circular dichroism data with those of related known compounds. It exhibited antifungal activity against Cryptococcus neoformans ATCC90113 flucytosine-resistant and Candida albicans NCPF3153 with the MIC values of 128 and 200 µg/mL, respectively. In addition, the known L-alanyl-L-tryptophan anhydride displayed TMEM16A inhibitory activity with 65.0% inhibition at a concentration of 5 µg/mL.

New aromatic polyketides from the marine-derived fungus Pseudopithomyces maydicus PSU-AMF350 and their antimicrobial activity.

Four new aromatic polyketides including two diphenyl ethers (pseudopithoethers A-B, 1-2), one benzofuranone (pseudopithonone, 3) and one xanthone (pseudopithoxanthone, 4), along with two known compounds (5-6) and one new naturally occurring hydroquinone (α,2,5-trihydroxyacetophenone, 7) were isolated from the marine-derived fungus Pseudopithomyces maydicus PSU-AMF350. Their structures were identified by analysis of spectroscopic data. All isolated compounds were tested for antimicrobial activity. Only compound 7 displayed antibacterial activity against methicillin-resistant Staphylococcus aureus with the MIC value of 128 µg/mL and against S. aureus, Acinetobacter baumannii NPRC005 and A. baumannii NPRC007 with the same MIC value of 200 µg/mL.[Formula: see text].

A fungus-derived purpactin A as an inhibitor of TMEM16A chloride channels and mucin secretion in airway epithelial cells.

TMEM16A is a Ca2+-activated Cl- channel involved in mucus secretion in inflamed airways and proposed as a drug target for diseases associated with mucus hypersecretion including asthma. This study aimed to identify novel inhibitors of TMEM16A-mediated Cl- secretion in airway epithelial cells from a collection of compounds isolated from fungi indigenous in Thailand and examine its potential utility in mitigating airway mucus secretion using Calu-3 cells as a study model. Screening of > 400 fungal metabolites revealed purpactin A isolated from a soil-derived fungus Penicillium aculeatum PSU-RSPG105 as an inhibitor of TMEM16A-mediated Cl- transport with an IC50 value of ~2 µM. A consistent inhibitory effect of purpactin A on TMEM16A were observed regardless of TMEM16A activators or in the presence of an inhibitor of Ca2+/calmodulin-dependent protein kinase II (CaMKII), a negative regulator of TMEM16A. In addition, purpactin A did not affect cell viability, epithelial barrier integrity and activities of membrane transport proteins essential for maintaining airway hydration including CFTR Cl- channels and apical BK K+ channels. Intriguingly, purpactin A prevented a Ca2+-induced mucin release in cytokine-treated airway cells. Taken together, purpactin A represents the first class of TMEM16A inhibitor derived from fungus, which may be beneficial for the treatment of diseases associated with mucus hypersecretion.

Cis-2 and trans-2-eisocenoic fatty acids are novel inhibitors for Mycobacterium tuberculosis Protein tyrosine phosphatase A.

Small protein tyrosine phosphatase (PtpA) of Mycobacterium tuberculosis is attributed to the development of latent tuberculosis infection, and hence bocomes an interesting target for drug development. In this communication, inhibition of PtpA by naturally occurring fatty acids cis-2 and trans-2-eicosenoic acid is investigated. Mtb PtpA was heterologously expressed in Escherichia coli, and the activity of PtpA was inhibited by cis-2 and trans-2 eicosenoic fatty acids. Both compunds showed strong inhibition of PtpA activity with IC50 at low micromolar concentration. As comparison, trans-11-eicosenoic acid only slightly inhibit PtpA. In silico analysis confirmed the inhibition of PtpB by cis-2-eicosenoic acid by formation of several hydrogen bonds. These findings show that cis-2 and trans-2 eicosenoic fatty acids are potential candidates for latent tuberculosis inhibitors.