Curcumin inhibits Aspergillus flavus infection and aflatoxin production possibly by inducing ROS burst

Mass spectrometry analysis of PM2.5 in poultry farms and the cytotoxicity and metabolism perturbation of BEAS-2B cells

To evaluate the potential risks posed by farm-derived fine particulate matter (PM2.5), we conducted a comprehensive analysis of PM2.5 samples collected from chicken farms. Specifically, water-soluble ions, metal and metalloids, and volatile organic compounds (VOCs) were quantitatively determined via ion chromatography, inductively coupled plasma mass spectrometry (ICP-MS), and gas chromatography‒mass spectrometry (GC‒MS), respectively. Furthermore, the microbial composition was elucidated through 16S ribosomal RNA (rRNA) high-throughput sequencing and ribosomal DNA (rDNA)-internal transcribed spacer (ITS) analysis. The study revealed that the water-soluble ion profile of PM2.5 was dominated by NO3-, NH4+, and SO42-, among others. Notably, aluminum, zinc, and manganese emerged as metals with relatively high concentrations. The primary VOCs identified were formic acid, acetic acid, and propionic acid. Microbiologically, Aspergillus and Faecalibacterium were the predominant genera detected. Upon exposure to PM2.5, BEAS-2B cells exhibited marked morphological alterations and a decrease in cell viability. Additionally, a dose-dependent increase in intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) levels was observed, accompanied by a decrease in superoxide dismutase (SOD) activity. This oxidative stress was further corroborated by elevated levels of inflammatory cytokines, including IL-6, IL-8, and TNF-α. Our findings suggest that livestock-generated PM2.5 significantly impacts cellular metabolism, particularly amino acid and nucleotide metabolism. Notably, PM2.5 from these environments can elicit cellular oxidative stress and inflammatory responses, which, with prolonged exposure, may lead to adverse health outcomes in both animals and humans. Therefore, the physical, chemical, and microbial characteristics of PM2.5 in poultry farms cannot be overlooked, emphasizing the critical need to improve the air quality within these facilities.

Inhibition Mechanism of Cinnamomum burmannii Leaf Essential Oil Against Aspergillus flavus and Aflatoxins

This investigation evaluates the comparative efficacy of Cinnamomum burmannii leaf essential oil (YXYO) and its main active ingredients as a novel preservative to protect stored food commodities from fungal infestations, aflatoxin B1 (AFB1) contamination caused by Aspergillus flavus. Morphological observations utilizing SEM and TEM revealed significant alterations in treated samples, alongside a decrease in ergosterol content and a dose-dependent disruption of the antioxidant system and energy system. Transcriptomic analysis suggested that differentially expressed genes were predominantly associated with spore growth, the cell wall, the cell membrane, oxidative stress, energy metabolism, and aflatoxin biosynthesis. Solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) identified ten active ingredients in YXYO, including borneol, α-terpineol, terpinen-4-ol, etc. Moreover, an effective inhibition of A. flavus infection in peanuts was observed with the application of 30 μL/disc of YXYO and a blend of its active compounds.

Research progress on inhibitors and inhibitory mechanisms of mycotoxin biosynthesis

Mycotoxins are secondary metabolites produced by fungi with harmful effects such as carcinogenicity, teratogenicity, nephrotoxicity, and hepatotoxicity. They cause widespread contamination of plant products such as crops, food, and feed, posing serious threats to the life and health of human beings and animals. It has been found that many traditionally synthesized and natural compounds are capable of inhibiting the growth of fungi and their secondary metabolite production. Natural compounds have attracted much attention due to their safety, environmental, and health friendly features. In this paper, compounds of plant origin with inhibitory effects on ochratoxins, aflatoxins, Fusarium toxins, and Alternaria toxins, including cinnamaldehyde, citral, magnolol, eugenol, pterostilbene, curcumin, and phenolic acid, are reviewed, and the inhibitory mechanisms of different compounds on the toxin production of fungi are also elucidated, with the aim of providing application references to reduce the contamination of fungal toxins, thus safeguarding the health of human beings and animals.

Unraveling the antifungal and anti-aflatoxin B1 mechanisms of piperitone on Aspergillus flavus

Aspergillus flavus infects important crops and produces carcinogenic aflatoxins, posing a serious threat to food safety and human health. Biochemical analysis and RNA-seq were performed to investigate the effects and mechanisms of piperitone on A. flavus growth and aflatoxin B1 biosynthesis. Piperitone significantly inhibited the growth of A. flavus, AFB1 production, and its pathogenicity on peanuts and corn flour. Differentially expressed genes (DEGs) associated with the synthesis of chitin, glucan, and ergosterol were markedly down-regulated, and the ergosterol content was reduced, resulting in a disruption in the integrity of the cell wall and cell membrane. Moreover, antioxidant genes were down-regulated, the correspondingly activities of antioxidant enzymes such as catalase, peroxidase, and superoxide dismutase were reduced, and levels of superoxide anion and hydrogen peroxide were increased, leading to a burst of reactive oxygen species (ROS). Accompanied by ROS accumulation, DNA fragmentation and cell autophagy were observed, and 16 aflatoxin cluster genes were down-regulated. Overall, piperitone disrupts the integrity of the cell wall and cell membrane, triggers the accumulation of ROS, causes DNA fragmentation and cell autophagy, ultimately leading to defective growth and impaired AFB1 biosynthesis.

The Synergistic Combination of Curcumin and Polydatin Improves Temozolomide Efficacy on Glioblastoma Cells

Glioblastoma (GBL) is one of the more malignant primary brain tumors; it is currently treated by a multimodality strategy including surgery, and radio- and chemotherapy, mainly consisting of temozolomide (TMZ)-based chemotherapy. Tumor relapse often occurs due to the establishment of TMZ resistance, with a patient median survival time of <2 years. The identification of natural molecules with strong anti-tumor activity led to the combination of these compounds with conventional chemotherapeutic agents, developing protocols for integrated anticancer therapies. Curcumin (CUR), resveratrol (RES), and its glucoside polydatin (PLD) are widely employed in the pharmaceutical and nutraceutical fields, and several studies have demonstrated that the combination of these natural products was more cytotoxic than the individual compounds alone against different cancers. Some of us recently demonstrated the synergistic efficacy of the sublingual administration of a new nutraceutical formulation of CUR+PLD in reducing tumor size and improving GBL patient survival. To provide some experimental evidence to reinforce these clinical results, we investigated if pretreatment with a combination of CUR+PLD can improve TMZ cytotoxicity on GBL cells by analyzing the effects on cell cycle, viability, morphology, expression of proteins related to cell proliferation, differentiation, apoptosis or autophagy, and the actin network. Cell viability was assessed using the MTT assay or a CytoSmart cell counter. CalcuSyn software was used to study the CUR+PLD synergism. The morphology was evaluated by optical and scanning electron microscopy, and protein expression was analyzed by Western blot. Flow cytometry was used for the cell cycle, autophagic flux, and apoptosis analyses. The results provide evidence that CUR and PLD, acting in synergy with each other, strongly improve the efficacy of alkylating anti-tumor agents such as TMZ on drug-resistant GBL cells through their ability to affect survival, differentiation, and tumor invasiveness.

Energy Metabolism Enhance Perylenequinone Biosynthesis in Shiraia sp. Slf14 through Promoting Mitochondrial ROS Accumulation

Perylenequinones (PQs) are important natural compounds that have been extensively utilized in recent years as agents for antimicrobial, anticancer, and antiviral photodynamic therapies. In this study, we investigated the molecular mechanisms regulating PQ biosynthesis by comparing Shiraia sp. Slf14 with its low PQ titer mutant, Slf14(w). The results indicated that the strain Slf14 exhibited a higher PQ yield, a more vigorous energy metabolism, and a more pronounced oxidation state compared to Slf14(w). Transcriptome analysis consistently revealed that the differences in gene expression between Slf14 and Slf14(w) are primarily associated with genes involved in redox processes and energy metabolism. Additionally, reactive oxygen species (ROS) were shown to play a crucial role in promoting PQ synthesis, as evidenced by the application of ROS-related inhibitors and promoters. Further results demonstrated that mitochondria are significant sources of ROS, which effectively regulate PQ biosynthesis in Shiraia sp. Slf14. In summary, this research revealed a noteworthy finding: the higher energy metabolism of the strain Slf14 is associated with increased intracellular ROS accumulation, which in turn triggers the activation and expression of gene clusters responsible for PQ synthesis.

Rhein Inhibits Cell Development and Aflatoxin Biosynthesis via Energy Supply Disruption and ROS Accumulation in Aspergillus flavus

Aspergillus flavus and its carcinogenic secondary metabolites, aflatoxins, not only cause serious losses in the agricultural economy, but also endanger human health. Rhein, a compound extracted from the Chinese herbal medicine Rheum palmatum L. (Dahuang), exhibits good anti-inflammatory, anti-tumor, and anti-oxidative effects. However, its effect and underlying mechanisms against Aspergillus flavus have not yet been fully illustrated. In this study, we characterized the inhibition effect of rhein on A. flavus mycelial growth, sporulation, and aflatoxin B1 (AFB1) biosynthesis and the potential mechanism using RNA-seq analysis. The results indicate that A. flavus mycelial growth and AFB1 biosynthesis were significantly inhibited by 50 μM rhein, with a 43.83% reduction in colony diameter and 87.2% reduction in AFB1 production. The RNA-seq findings demonstrated that the differentially expressed genes primarily participated in processes such as spore formation and development, the maintenance of cell wall and membrane integrity, management of oxidative stress, the regulation of the citric acid cycle, and the biosynthesis of aflatoxin. Biochemical verification experiments further confirmed that 50 μM rhein effectively disrupted cell wall and membrane integrity and caused mitochondrial dysfunction through disrupting energy metabolism pathways, leading to decreased ATP synthesis and ROS accumulation, resulting in impaired aflatoxin biosynthesis. In addition, a pathogenicity test showed that 50 μM rhein inhibited A. flavus spore growth in peanut and maize seeds by 34.1% and 90.4%, while AFB1 biosynthesis was inhibited by 60.52% and 99.43%, respectively. In conclusion, this research expands the knowledge regarding the antifungal activity of rhein and provides a new strategy to mitigate A. flavus contamination.

The potential of antifungal peptides derived from Lactiplantibacillus plantarum WYH for biocontrol of Aspergillus flavus contamination

Aspergillus flavus is a notorious fungus that contaminates food crops with toxic aflatoxins, posing a serious threat to human health and the agricultural economy. To overcome the inadequacy of traditional control methods and meet consumer preferences for natural-sources additives, there is an urgent demand for novel biocontrol agents that are safe and efficient. This study aims to investigate the antifungal properties of a novel antifungal agent derived from the biologically safe Lactiplantibacillus plantarum WYH. Firstly, antifungal peptides (AFPs) with a molecular weight of less than 3kD, exhibiting remarkable temperature stability and effectively retarding fungal growth in a dose-dependent manner specifically against A. flavus, were concentrated from the fermentation supernatant of L. plantarum WYH and were named as AFPs-WYH. Further analysis demonstrated that AFPs-WYH might exert antifungal effects through the induction of oxidative stress, disruption of mitochondrial function, alteration of membrane permeability, and cell apoptosis in A. flavus. To further validate our findings, a transcriptomics analysis was conducted on A. flavus treated with 2 and 5 mg/mL of AFPs-WYH, which elucidated the potential effect of AFPs-WYH administration on the regulation of genes involved in impairing fungal development and preventing aflatoxin biosynthesis pathways. Overall, AFPs-WYH reduced the A. flavus proliferation and affected the AFB1 biosynthesis, exhibiting a promising potential for food industry applications as a biopreservative and biocontrol agent.

Curcumin: An innovative approach for postharvest control of Alternaria alternata induced black rot in cherry tomatoes

Curcumin, a natural bioactive compound derived from Curcuma longa, has been widely recognized for its antifungal properties. In this study, we investigated the effects of curcumin on the phytopathogenic fungus Alternaria alternata and its pathogenicity in cherry tomato fruit. The results demonstrated that curcumin treatment significantly inhibited mycelial growth and spore germination of A. alternata in a dose-dependent manner. Scanning electron microscopy revealed alterations in the morphology of A. alternata mycelia treated with curcumin. Furthermore, curcumin treatment led to an increase in malondialdehyde and hydrogen peroxide contents, indicating cell membrane damage in A. alternata. Moreover, curcumin exhibited a remarkable inhibitory effect on the incidence and lesion diameters of black rot caused by A. alternata in cherry tomato fruit. Gene expression analysis revealed upregulation of defense-related genes (POD, SOD, and CAT) in tomato fruit treated with curcumin. Additionally, curcumin treatment resulted in decreased activity of exocellular pathogenic enzymes (polygalacturonase, pectin lyase, and endo-1,4-β-d-glucanase) in A. alternata. Overall, our findings highlight the potential of curcumin as an effective antifungal agent against A. alternata, providing insights into its inhibitory mechanisms on mycelial growth, spore germination, and pathogenicity in cherry tomato fruit.

Antifungal and elicitor activities of p-hydroxybenzoic acid for the control of aflatoxigenic Aspergillus flavus in kiwifruit

Aspergillus flavus not only reduces kiwifruit production but also synthesizes carcinogenic aflatoxins, resulting in a relevant threat to human health. p-Hydroxybenzoic acid (pHBA) is one of the most abundant phenolics in kiwifruit. In this study, pHBA was found to reduce A. flavus mycelial growth by blocking the fungal mitotic exit network (MEN) and cytokinesis and to inhibit the biosynthesis of aflatoxins B1 and B2. The application of pHBA promoted the accumulation of endogenous pHBA and induced oxidative stress in A. flavus-infected kiwifruit, resulting in an increase in H2O2 content and catalase (CAT) and superoxide dismutase (SOD) activities. Preventive and curative treatments with 5 mM pHBA reduced A. flavus advancement by 46.1% and 68.0%, respectively. Collectively, the antifungal and elicitor properties of pHBA were examined for the first time, revealing new insights into the role of pHBA in the defense response of kiwifruit against A. flavus infection.

Stand Up to Stand Out: Natural Dietary Polyphenols Curcumin, Resveratrol, and Gossypol as Potential Therapeutic Candidates against Severe Acute Respiratory Syndrome Coronavirus 2 Infection

The COVID-19 pandemic has stimulated collaborative drug discovery efforts in academia and the industry with the aim of developing therapies and vaccines that target SARS-CoV-2. Several novel therapies have been approved and deployed in the last three years. However, their clinical application has revealed limitations due to the rapid emergence of viral variants. Therefore, the development of next-generation SARS-CoV-2 therapeutic agents with a high potency and safety profile remains a high priority for global health. Increasing awareness of the "back to nature" approach for improving human health has prompted renewed interest in natural products, especially dietary polyphenols, as an additional therapeutic strategy to treat SARS-CoV-2 patients, owing to its good safety profile, exceptional nutritional value, health-promoting benefits (including potential antiviral properties), affordability, and availability. Herein, we describe the biological properties and pleiotropic molecular mechanisms of dietary polyphenols curcumin, resveratrol, and gossypol as inhibitors against SARS-CoV-2 and its variants as observed in in vitro and in vivo studies. Based on the advantages and disadvantages of dietary polyphenols and to obtain maximal benefits, several strategies such as nanotechnology (e.g., curcumin-incorporated nanofibrous membranes with antibacterial-antiviral ability), lead optimization (e.g., a methylated analog of curcumin), combination therapies (e.g., a specific combination of plant extracts and micronutrients), and broad-spectrum activities (e.g., gossypol broadly inhibits coronaviruses) have also been emphasized as positive factors in the facilitation of anti-SARS-CoV-2 drug development to support effective long-term pandemic management and control.