Citrinin (CIT) is a mycotoxin commonly found in grains, fruits, herbs, and spices. Its toxicity primarily affects the kidney and liver. Meanwhile, food industry by-products, particularly from fishing and aquaculture, contribute significantly to environmental concerns but can also serve as valuable sources of nutrients and bioactive compounds. Additionally, microalgae like spirulina (Arthrospira platensis) offer interesting high-added-value compounds with potential biological and cytoprotective properties. This study aims to reduce CIT\'s toxicity on SH-SY5Y cells using natural extracts from the microalgae spirulina and fish processing by-products (sea bass head). The combination of these extracts with CIT has shown increased cell viability up to 15% for fish by-products extract and about 10% for spirulina extract compared to CIT alone. Furthermore, a notable reduction of up to 63.2% in apoptosis has been observed when fish by-products extracts were combined with CIT, counteracting the effects of CIT alone. However, the extracts\' effectiveness in preventing CIT toxicity in the cell cycle remains unclear. Overall, considering these nutrient and bioactive compound sources is crucial for enhancing food safety and mitigating the harmful effects of contaminants such as mycotoxins. Nevertheless, further studies are needed to investigate their mechanisms of action and better understand their protective effects more comprehensively.

Dietary supplements containing red yeast rice (RYR), a fermentation product of the fungus Monascus purpureus grown on white rice, remain popular in Europe as proclaimed cholesterol-lowering aids. The cholesterol-lowering effects are due to the occurrence of monacolin K, which is often present as a mixture of monacolin K lactone (MK) and as monacolin K hydroxy acid (MKA). MK is structurally similar to the cholesterol-lowering medicine lovastatin. Recently, due to safety concerns linked to the use of statins, the European Commission prohibited RYR supplements with a maximum serving exceeding 3 mg of total monacolins per day. Moreover, the amount of the mycotoxin citrinin, potentially produced by M. purpureus, was also reduced to 100 µg/kg. Evidently, manufacturers that offer their products on the European market, including the online market, must also be compliant with these limits in order to guarantee the safety of their products. Therefore, thirty-five different RYR supplements, purchased from an EU-bound e-commerce platform or from registered online pharmacies, were screened for their compliance to the European legislation for citrinin content and the amount of total monacolin K. This was conducted by means of a newly developed LC-MS/MS methodology that was validated according to ISO 17025. Moreover, these supplements were also screened for possible adulteration and any contamination by micro-organisms and/or mycotoxins. It was found that at least four of the thirty-five RYR supplements (≈11%) might have reason for concern for the safety of the consumer either due to high total monacolin K concentrations exceeding the European predefined limits for total monacolins or severe bacterial contamination. Moreover, three samples (≈9%) were likely adulterated, and the labeling of six of the seventeen samples (≈35%) originating from an EU-based e-commerce platform was not compliant, as either the mandatory warning was missing or incomplete or the total amount of monacolins was not mentioned.

Monascus species are functional fermentation fungi with great potential for selenium (Se) supplementation. This study investigated the effects of Se bio-fortification on the growth, morphology, and biosynthesis of Monascus ruber M7. The results demonstrated a significant increase in the yield of orange and red Monascus pigments (MPs) in red yeast rice (RYR) by 38.52% and 36.57%, respectively, under 20 μg/mL of selenite pressure. Meanwhile, the production of citrinin (CIT), a mycotoxin, decreased from 244.47 μg/g to 175.01 μg/g. Transcriptome analysis revealed significant upregulation of twelve genes involved in MPs biosynthesis, specifically MpigE, MpigF, and MpigN, and downregulation of four genes (mrr3, mrr4, mrr7, and mrr8) associated with CIT biosynthesis. Additionally, three genes encoding cysteine synthase cysK (Log2FC = 1.6), methionine synthase metH (Log2FC = 2.2), and methionyl-tRNA synthetase metG (Log2FC = 1.8) in selenocompound metabolism showed significantly upregulated. These findings provide insights into Se biotransformation and metabolism in filamentous fungi.

Citrinin is a hepato-nephrotoxic mycotoxin produced by fungal species. The Monascus purpureus fungus plays a crucial role in the fermentation of red rice to produce red yeast rice-based food supplements, which represent the primary source of human exposure to citrinin. In this study, a simple and sensitive analytical method was successfully developed and validated for the citrinin determination in these products. The extraction process involved a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) step and citrinin determination by ultra high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). The proposed method provided satisfactory linearity, percentage of recovery from 82 to 104% with relative standard deviations (RSD) lower than 14%, and limits of detection and quantification of 0.07 μg/Kg and 0.24 μg/kg, respectively. Among the 14 samples analyzed, citrinin was found in two red rice samples (0.24 and 0.46 μg/kg) and in six food supplements (from 0.44 to 87 μg/kg).

Two new cytochalasin derivatives, peniotrinins A (1) and B (2), three new citrinin derivatives, peniotrinins C-E (4, 5, 7), and one new tetramic acid derivative, peniotrinin F (12), along with nine structurally related known compounds, were isolated from the solid culture of Peniophora sp. SCSIO41203. Their structures, including the absolute configurations of their stereogenic carbons, were fully elucidated based on spectroscopic analysis, quantum chemical calculations, and the calculated ECD. Interestingly, 1 is the first example of a rare 6/5/5/5/6/13 hexacyclic cytochalasin. We screened the above compounds for their anti-prostate cancer activity and found that compound 3 had a significant anti-prostate cancer cell proliferation effect, while compounds 1 and 2 showed weak activity at 10 μM. We then confirmed that compound 3 exerts its anti-prostate cancer effect by inducing methuosis through transmission electron microscopy and cellular immunostaining, which suggested that compound 3 might be first reported as a potential anti-prostate methuosis inducer.

Pear residue, a byproduct of pear juice extraction, is rich in soluble sugar, vitamins, minerals, and cellulose. This study utilized Monascus anka in liquid fermentation to extract dietary fiber (DF) from pear residue, and the structural and functional characteristics of the DF were analyzed. Soluble DF (SDF) content was increased from 7.9/100 g to 12.6 g/100 g, with a reduction of average particle size from 532.4 to 383.0 nm by fermenting with M. anka. Scanning electron microscopy and infrared spectroscopic analysis revealed more porous and looser structures in Monascus pear residue DF (MPDF). Water-, oil-holding, and swelling capacities of MPDF were also enhanced. UV-visible spectral analysis showed that the yield of yellow pigment in Monascus pear residue fermentation broth (MPFB) was slightly higher than that in the Monascus blank control fermentation broth. The citrinin content in MPFB and M. anka seed broth was 0.90 and 0.98 ug/mL, respectively. Therefore, liquid fermentation with M. anka improved the structural and functional properties of MPDF, suggesting its potential as a functional ingredient in food.

Monascus is a filamentous fungus that has been used in the food and pharmaceutical industries. When used as an auxiliary fermenting agent in the manufacturing of cheese, Monascus cheese is obtained. Citrinin (CIT) is a well-known hepatorenal toxin produced by Monascus that can harm the kidneys structurally and functionally and is frequently found in foods. However, CIT contamination in Monascus cheese is exacerbated by the metabolic ability of Monascus to product CIT, which is not lost during fermentation, and by the threat of contamination by Penicillium spp. that may be introduced during production and processing. Considering the safety of consumption and subsequent industrial development, the CIT contamination of Monascus cheese products needs to be addressed. This review aimed to examine its occurrence in Monascus cheese, risk implications, traditional control strategies, and new research advances in prevention and control to guide the application of biotechnology in the control of CIT contamination, providing more possibilities for the application of Monascus in the cheese industry.

Penicilloneines A (1) and B (2) are the first reported quinolone-citrinin hybrids. They were isolated from the starfish-derived fungus Penicillium sp. GGF16-1-2, and their structures were elucidated using spectroscopic, chemical, computational, and single-crystal X-ray diffraction methods. Penicilloneines A (1) and B (2) share a common 4-hydroxy-1-methyl-2(1H)-quinolone unit; however, they differ in terms of citrinin moieties, and these two units are linked via a methylene bridge. Penicilloneines A (1) and B (2) exhibited antifungal activities against Colletotrichum gloeosporioides, with lethal concentration 50 values of 0.02 and 1.51 μg/mL, respectively. A mechanistic study revealed that 1 could inhibit cell growth and promote cell vacuolization and consequent disruption of the fungal cell walls via upregulating nutrient-related hydrolase genes, including putative hydrolase, acetylcholinesterase, glycosyl hydrolase, leucine aminopeptidase, lipase, and beta-galactosidase, and downregulating their synthase genes 3-carboxymuconate cyclase, pyruvate decarboxylase, phosphoketolase, and oxalate decarboxylase.

Mycotoxins can be found in food and feed storage as well as in several kinds of foodstuff and are capable of harming mammals and some of them even in small doses. This study investigated on the undifferentiated neuronal cell line SH-SY5Y the effects of two mycotoxins: patulin (PAT) and citrinin (CTN), which are predominantly produced by fungi species Penicillium and Aspergillus. Here, the individual and combined cytotoxicity of PAT and CTN was investigated using the cytotoxic assay MTT. Our findings indicate that after 24 h of treatment, the IC50 value for PAT is 2.01 μM, which decreases at 1.5 μM after 48 h. In contrast, CTN did not attain an IC50 value at the tested concentration. Therefore, we found PAT to be the more toxic compared to CTN. However, the combined treatment suggests an additive toxic effect. With 2,7-dichlorodihydrofluorescin diacetate (DCFH-DA) DCFH-DA assay, ROS generation was demonstrated after CTN treatment, but PAT showed only small changes. The mixture presented a very constant behavior over time. Finally, the median-effect/combination index (CI-) isobologram equation demonstrated an additive effect after 24 h, but an antagonistic effect after 48 h for the interaction of the two mycotoxins.

Penicillium citrinum GZWMJZ-836 is an endophytic fungus from Drynaria roosii Nakaike. Five previously undescribed citrinin derivatives (1-5) and six intermediates related to their biosynthesis (6-11) were obtained from the extract of this strain\'s solid fermentation using multiple column chromatography separations, including high-performance liquid chromatography. The structures of these compounds were determined through comprehensive spectroscopic analyses, primarily using NMR and HRESIMS data. The stereochemistry was mainly confirmed by ECD calculations, and the configurations of C-7\' in compounds 4 and 5 were determined using 13C NMR calculations. Compounds 4-5 and 8 showed antibacterial activity against five strains, with minimum inhibitory concentration values ranging from 7.8 to 125 μM. Compounds 4 and 7 exhibited inhibitions against three plant pathogenic fungi, with IC50 values ranging from 66.6 to 152.1 μM. Additionally, a putative biosynthetic pathway for compounds 1-5 derived from citrinin was proposed.