Terminal carboxylation of branched carbon chain contributing to acidic stability of azaphilone pigments from a new isolate of Talaromyces amestolkiae

Teratogenic effect evaluation of Monascus red oral exposure to pregnant rats and their gut microbiota

Monascus red (MR) is widely used as a natural food colorant and preservative in East Asia. However, the potential effects of MR during pregnancy remains unknown. In this study, MR was administrated to Sprague-Dawley (SD) rats at doses of 0, 0.50, 1.58, and 5.00 g/kg bw on gestational days 6-15 by oral gavage. In the maternal and embryo-fetal examinations, there were no marked toxicities in terms of general clinical signs, body weight, food consumption, serum endocrine indices, organ weights, thyroid histopathology, examinations of uterine contents and fetuses. In the gut microbiota analysis, the 5.00 g/kg bw dose of MR decreased the α diversity and slightly changed their community structure at the genus level. Yet no marked toxicities in maternal animals or embryo-fetal development were observed. The no-observed-adverse-effect-level (NOAEL) of the maternal and developmental toxicity through oral exposure to MR was 5.00 g/kg bw, the highest dose tested in rats.

Improving the color stability of red Monascus pigments by direct protein microgelation

The application of red Monascus pigments (RMPs) in food storage as well as food processing usually endures harsh environmental conditions. Here, we presented a new encapsulation strategy to improve the stability of RMPs. At first, we managed to realize the azaphilic substitution reaction between orange Monascus pigments (OMPs) and soy protein to produce water-soluble RMPs, i.e., soy protein chemically modified by OMPs. Then, the as-prepared RMPs as a kind of protein were directly utilized to fabricate microgels where microgel efficiency > 60 % (encapsulation of RMPs in microgels > 60 %) was achieved after optimization of Ca2+ and RMP concentrations. The microgels with particle sizes < 10 μm dispersed very well in water. The stability of encapsulated RMPs in microgels under harsh environmental conditions, such as heating, acidic pH, and sunlight irradiation, had improved approximately 10-20 % compared with that of free RMPs under the same condition.

Unveiling the fungal color palette: pigment analysis of Fusarium solani species complex and Curvularia verruculosa clinical isolates

Fungal species in the Nectriaceae, such as Fusarium spp. (Hypocreales: Nectriaceae), are etiologic agents of hyalohyphomycosis capable of producing violaceous or yellowish pigments under certain conditions, while Curvularia spp. (Pleosporales: Pleosporaceae) are agents of phaeohyphomycosis and typically produce melanin in their cell walls. In nectriaceous and pleosporaceous fungi, these pigments are mainly constituted by polyketides (e.g., azaphilones, naphthoquinones, and hydroxyanthraquinones). Considering the importance of pigments synthesized by these genera, this work focused on the selective extraction of pigments produced by eight Fusarium solani species complex and one Curvularia verruculosa isolate recovered from dermatomycosis specimens, their separation, purification, and posterior chemical analysis. The pigments were characterized through spectral and acid-base analysis, and their maximum production time was determined. Moreover, spectral identification of isolates was carried out to approach the taxonomic specificity of pigment production. Herein we describe the isolation and characterization of three acidic pigments, yellowish and pinkish azaphilones (i.e., coaherin A and sclerotiorin), and a purplish xanthone, reported for the first time in the Nectriaceae and Pleosporaceae, which appear to be synthesized in a species-independent manner, in the case of fusaria.

Bioactive polyketides and meroterpenoids from the mangrove-derived fungus Talaromyces flavus TGGP35

Six new polyketides, which includes three new lactones (talarotones A-C) (1-3), one new polyketide (talarotide A) (4), two new polyenes (talaroyenes A, B) (5, 6), together with one new meroterpenoid (talaropenoid A) (7) and 13 known compounds (8-20) were isolated from the mangrove-derived fungus Talaromyces flavus TGGP35. The structure and configuration of the compounds 1-7 were elucidated from the data obtained from HR-ESI-MS, IR, 1D/2D NMR spectroscopy, Mo2 (OAc)4-induced electronic circular dichroism (ECD), CD spectroscopy, and modified Mosher's method. Compounds 5 and 20 displayed antioxidant activity with IC50 values of 0.40 and 1.36 mM, respectively. Compounds 3, 6, 11, 16, and 17 displayed cytotoxic activity against human cancer cells Hela, A549, and had IC50 values ranging from 28.89 to 62.23 μM. Compounds 7, 10-12, and 14-18 exhibited moderate or potent anti-insect activity against newly hatched larvae of Helicoverpa armigera Hubner, with IC50 values in the range 50-200 μg/mL. Compound 18 showed antibacterial activity against Ralstonia solanacearum with the MIC value of 50 μg/mL.