Pigments of fungal origin have aroused increasing interest in the food dye and cosmetic industries since the global demand for natural dyes has grown. Endophytic microorganisms are a source of bioactive compounds, and Amazonian plant species can harbor fungi with a wide range of biotechnological applications. Popularly known in Brazil as crajiru, Fridericia chica is a medicinal plant that produces a red pigment. In this study, a total of 121 fungi were isolated in potato dextrose agar from three plants. We identified nine pigment-producing endophytic fungi isolated from branches and leaves of F. chica. The isolates that showed pigment production in solid media were molecularly identified via multilocus analysis as Aspergillus welwitschiae, A. sydowii, Curvularia sp., Diaporthe cerradensis (two strains), Hypoxylon investiens, Neoscytalidium sp. (two strains) and Penicillium rubens. These isolates were subjected to submerged fermentation in two culture media to obtain metabolic extracts. The extracts obtained were analyzed in terms of their absorbance between 400 and 700 nm. The pigmented extract produced by H. investiens in medium containing yeast extract showed maximum absorbance in the red absorption range (UA₇₀₀ = 0.550) and significant antioxidant and antimicrobial activity. This isolate can thus be considered a new source of extracellular pigment.

Endophytic fungi are promising producers of phenolic compounds; however, the process of extracting these molecules from the culture medium is a crucial step for obtaining these metabolites. In this context, the best conditions for extracting phenolic compounds produced by Cophinforma mamane CF2-13, isolated from an Amazonian plant, were evaluated. The fungus was cultivated in a liquid medium to obtain its metabolites. The effects of the solvent, time, and temperature were investigated, as well as the use of ultrasound. The total phenolics and the antioxidant activity were assessed to define the best extraction conditions. The optimized extract was chemically characterized and used to analyze its potential in protecting olive oil from lipid oxidation. The best results were found using ethyl acetate at 20 °C for 2 h. These conditions led to 61.61 mg GAEq/g of extract of total phenolics, and an antioxidant capacity of 0.47, 0.45, and 0.29 mmol TEq/g of extract using the DPPH, ABTS, and FRAP methods, respectively. In addition, the optimized extract presented caffeic acid and was able to delay the lipid oxidation of olive oil. The potential of endophytic fungi to produce phenolic compounds is promising for the food industry since natural bioactive compounds have many benefits for human health.

Pectinolytic enzymes play a key role in many beverages manufacturing processes, improving their clarification and filtration steps. Fungal pectinases are considered promising green catalysts for industrial applications, and they can be produced using fruit-processing residues as substrate. In this study, we investigated the optimal conditions to produce polygalacturonase from Aspergillus brasiliensis in a solid-phase bioprocess, using cupuaçu (Theobroma grandiflorum) peel as substrate. Then, the pectinolytic extract was applied in the clarification of cupuaçu juice. A central composite design was used to determine the optimal fungal cultivation conditions. Thus, the optimal fungal cultivation (maximum production of 11.81 U/g of polygalacturonase) was obtained using cupuaçu peel with 80% moisture, at 34 °C, for 7 days in a medium containing 4.2% phosphorus and 2.6% nitrogen. The enzymatic extract showed greater activity at 60 °C and stability at a pH range between 5.0 and 7.0. The pectinolytic extract was able to clarify the cupuaçu juice, causing a 53.95% reduction in its turbidity and maintaining its antioxidant activity. Our results demonstrate that the cupuaçu peel can be used as a substrate to produce polygalacturonase, and the enzymatic extract produced can be applied in the cupuaçu juice processing, contributing to the circular economy.

Endophytic fungi are recognized for their capacity to produce bioactive metabolites, yet their metabolic output is strongly modulated by preservation strategies. This study evaluated the influence of three long-term preservation methods—PDA slants with mineral oil (PB), Castellani’s method (PC), and filter paper with mineral oil (PF)—on the production of phenolic compounds and antioxidant activity by the Amazonian endophytes Cophinforma mamane and Aspergillus niger. Post-reactivation morphological analyses revealed method-dependent changes in colony pigmentation, texture, and sporulation intensity. PB preservation induced the most vigorous growth and enhanced sporulation in A. niger. For extracellular metabolites (AcOEt extracts), PB yielded the highest total phenolic content in A. niger (258.24 mg GAE/g), whereas PF and PC favored C. mamane (154.48 and 153.33 mg GAE/g). For intracellular ethanolic extracts, PB was most effective for C. mamane, producing 206.19 mg GAE/g for total phenols and the highest antioxidant activities (EC₅₀ = 1.40 mg/mL and FRAP = 95.61 µmol TE/g). HPLC–DAD identified protocatechuic acid as the predominant compound, which was especially abundant in PC and PF-preserved A. niger (60.76 and 85.38 µg/mg, respectively). Multivariate correlations indicated syringic (r = 0.53) and p-coumaric (r = 0.63) acids as the main contributors to antioxidant potential. These findings demonstrate that preservation methods may positively or negatively modulate fungal biosynthetic capacity, underscoring the importance of species-specific preservation protocols for maintaining metabolic stability in culture collections.

Cecropia sp. (Urticaceae) are commonly used in traditional medicine in South American countries for the treatment of different diseases. To date, the species Cecropia concolor Willd, of Amazonian occurrence, has not been investigated for its pharmacological potential. In this study, we described the chemical profile and the antileishmanial, antioxidant and cytotoxic activities of extracts of the leaves of C. concolor. The ethanolic extract and its partition phases (hexane, ethyl acetate and hydroethanolic) were analyzed for their chemical classes and phenolic content. Antileishmanial activity was assessed against Leishmania (L.) amazonensis. The antioxidant activity was evaluated using the DPPH method and in MRC-5 human fibroblast cells. Toxicity was tested against Artemia salina and in human cells (fibroblasts and cancer lines). The leaves of C. concolor have phenolic substances, such as flavonoids, as well as terpenes, steroids and alkaloids. Chlorogenic acid, caffeic acid, schaftoside and vicenin 2 were identified. The hydroethanolic phase showed a high concentration of phenolic compounds and pronounced antioxidant activity. The antileishmanial activity was observed in the ethanolic extract, with a promising effect of the hexane phase. The C. concolor ethanolic extract and its phases are non-toxic, which makes this species of interest in pharmaceutical and cosmetics applications.

Background/Objectives: Antimicrobial resistance and biofilm-associated infections have intensified the search for new bioactive molecules from natural sources. This study evaluated the antibacterial activity, effects on biofilm biomass, preliminary cytotoxicity, and chemical profiles of ethyl acetate extracts obtained from Amazonian endophytic fungi against Staphylococcus aureus CCCD-S009. Methods: Ten fungal extracts were evaluated using broth microdilution and crystal violet-based biofilm assays. Additional experiments assessed biofilm biomass during formation and the reduction in preformed biofilm biomass at the minimum inhibitory concentration (MIC) and half the MIC (0.5× MIC). Complementary experiments with Talaromyces pinophilus CCM-UEA-F0408 included testing across multiple concentrations and qualitative microscopy. Cytotoxicity was evaluated in MRC-5 human fibroblasts, and chemical characterization included thin-layer chromatography, total phenolic content determination, and HPLC-PDA analysis of selected phenolic acids. Results: Nine extracts showed antibacterial activity, with Cophinforma mamane CCM-UEA-F0869 and Penicillium jenningsiae CCM-UEA-F0773 exhibiting the lowest MICs (312.5 µg/mL). Nine extracts reduced crystal violet-stained biofilm biomass during formation by more than 50%. At 0.5× MIC, reductions in biofilm biomass ranged from 73.40% to 86.94%. Removal of preformed biofilm biomass was less consistent and varied with extract concentration and exposure time. At 50 µg/mL, seven extracts maintained MRC-5 cell viability above 90%, whereas T. pinophilus CCM-UEA-F0695 and P. jenningsiae CCM-UEA-F0773 markedly reduced cell viability. Preliminary chemical analyses revealed differences among extracts, and targeted HPLC-PDA profiling indicated the presence of caffeic, 4-hydroxybenzoic, gallic, and vanillic acids in selected fungal extracts. Conclusions: Amazonian endophytic fungal extracts exhibited distinct antibacterial, biofilm-related, and cytotoxicity profiles. The reduction in biofilm biomass observed at sub-MICs supports further investigation of these extracts as potential sources of bioactive compounds. However, biofilm-specific effects cannot be distinguished from growth inhibition using the present assays alone.