Beauvericin and enniatins H, I and MK1688 are new potent inhibitors of human immunodeficiency virus type-1 integrase

In vitro assessment of emerging mycotoxins co-occurring in cheese: a potential health hazard

Some Penicillium strains used in cheese ripening produce emerging mycotoxins, notably roquefortine C (ROQC) and cyclopiazonic acid (CPA), as well as enniatins (ENNs) and beauvericin (BEA). Co-occurrence of these mycotoxins in natural samples has been reported worldwide, however, most studies focus on the toxicity of a single mycotoxin. In the present study, the effects of ROQC and CPA alone and in combination with BEA and ENNs A, A1, B, and B1 were analysed in human neuroblastoma cells. ROQC and CPA reduced cell viability, with IC50 values of 49.5 and 7.3 µM, respectively, and induced caspase-8-mediated apoptosis. When ROQC and CPA were binary combined with ENNs, an enhancement of their individual effects was observed. Furthermore, a clear synergism was produced when ROQC and CPA were mixed with the four ENNs. An additive effect was also described for the combination of CPA + ENNs (A, A1, B, B1) + BEA. Finally, the effects of commercial cheese extracts containing the mentioned mycotoxins were evaluated, finding a strong reduction in cell viability. These results suggest that the co-occurrence of emerging mycotoxins in natural matrices could pose a potential health risk.

Exploring potential molecular targets and therapeutic efficacy of beauvericin in triple-negative breast cancer cells

Triple negative breast cancer (TNBC) presents a significant global health concern due to its aggressive nature, high mortality rate and limited treatment options, highlighting the urgent need for targeted therapies. Beauvericin, a bioactive fungal secondary metabolite, possess significant anticancer potential, although its molecular targets in cancer cells remain unexplored. This study has investigated possible molecular targets of beauvericin and its therapeutic insights in TNBC cells. In silico studies using molecular docking and MD simulation predicted the molecular targets of beauvericin. The identified targets included MRP-1 (ABCC1), HDAC-1, HDAC-2, LCK and SYK with average binding energy of -90.1, -44.3, -72.1, -105 and -60.8 KJ/mol, respectively, implying its multifaceted roles in reversing drug resistance, inhibiting epigenetic modulators and oncogenic tyrosine kinases. Beauvericin has significantly reduced the viability of MDA-MB-231 and MDA-MB-468 cells, with IC50 concentrations of 4.4 and 3.9 µM, while concurrently elevating the intracellular ROS by 9.0 and 7.9 folds, respectively. Subsequent reduction of mitochondrial transmembrane potential in TNBC cells, has confirmed the induction of oxidative stress, leading to apoptotic cell death, as observed by flow cytometric analyses. Beauvericin has also arrested cell cycle at G1-phase and impaired the spheroid formation and clonal expansion abilities of TNBC cells. The viability of spheroids was reduced upon beauvericin treatment, exhibiting IC50 concentrations of 10.3 and 6.2 µM in MDA-MB-468 and MDA-MB-231 cells, respectively. In conclusion, beauvericin has demonstrated promising therapeutic potential against TNBC cells through possible inhibition of MRP-1 (ABCC1), HDAC-1, HDAC-2, LCK and SYK.

Beauvericin Reverses Epithelial-to-Mesenchymal Transition in Triple-Negative Breast Cancer Cells through Regulation of Notch Signaling and Autophagy

Metastasis stands as a prime contributor to triple-negative breast cancer (TNBC) associated mortality worldwide, presenting heightened severity and significant challenges due to limited treatment options. Addressing TNBC metastasis necessitates innovative approaches and novel therapeutics to specifically target its propensity for dissemination to distant organs. Targeted therapies capable of reversing epithelial-to-mesenchymal transition (EMT) play a crucial role in suppressing metastasis and enhancing the treatment response. Beauvericin, a promising fungal secondary metabolite, exhibits significant potential in diminishing the viability of EMT-induced TNBC cells by triggering intracellular oxidative stress, as evidenced by an enhanced reactive oxygen species level and reduced mitochondrial transmembrane potential. In monolayer cultures, it has exhibited an IC50 of 2.3 μM in both MDA-MB-468 and MDA-MB-231 cells, while in 3D spheroids, the IC50 values are 9.7 and 7.1 μM, respectively. Beauvericin has also reduced the migratory capability of MDA-MB-468 and MDA-MB-231 cells by 1.5- and 1.7-fold, respectively. Both qRT-PCR and Western blot analysis have shown significant upregulation in the expression of epithelial marker (E-cadherin) and downregulation in the expression of mesenchymal markers (N-cadherin, vimentin, Snail, Slug, and β-catenin), following treatment, indicating reversal of EMT. Furthermore, beauvericin has suppressed the Notch signaling pathway by substantially downregulating Notch-1, Notch-3, Hes-1, and cyclinD3 expression and induced autophagy as observed by elevated expression of autophagy markers LC3 and Beclin-1. In conclusion, beauvericin has successfully downregulated TNBC cell survival by inducing oxidative stress and suppressed their migratory potential by reversing EMT through the inhibition of Notch signaling and activation of autophagy.

Computational Applications: Beauvericin from a Mycotoxin into a Humanized Drug

Drug discovery was initially attributed to coincidence or experimental research. Historically, the traditional approaches were complex, lengthy, and expensive, entailing costly random screening of synthesized compounds or natural products coupled with in vivo validation largely depending on the availability of appropriate animal models. Currently, in silico modeling has become a vital tool for drug discovery and repurposing. Molecular docking and dynamic simulations are being used to find the best match between a ligand and a molecule, an approach that could help predict the biomolecular interactions between the drug and the target host. Beauvericin (BEA) is an emerging mycotoxin produced by the entomopathogenic fungus Beauveria bassiana, being originally studied for its potential use as a pesticide. BEA is now considered a molecule of interest for its possible use in diverse biotechnological applications in the pharmaceutical industry and medicine. In this manuscript, we provide an overview of the repurposing of BEA as a potential therapeutic agent for multiple diseases. Furthermore, considerable emphasis is given to the fundamental role of in silico techniques to (i) further investigate the activity spectrum of BEA, a secondary metabolite, and (ii) elucidate its mode of action.

Low beauvericin concentrations promote PC-12 cell survival under oxidative stress by regulating lipid metabolism and PI3K/AKT/mTOR signaling

Beauvericin (BEA), a naturally occurring cyclic peptide with good pharmacological activity, has been widely explored in anticancer research. Although BEA is toxic, studies have demonstrated its antioxidant activity. However, to date, the antioxidant mechanisms of BEA remain unclear. Herein, we conducted a comprehensive and detailed study of the antioxidant mechanism of BEA using an untargeted metabolomics approach, subsequently validating the results. BEA concentrations of 0.5 and 1 μM significantly inhibited H2O2-induced oxidative stress (OS), decreased reactive oxygen species levels in PC-12 cells, and restored the mitochondrial membrane potential. Untargeted metabolomics indicated that BEA was primarily involved in lipid-related metabolism, suggesting its role in resisting OS in PC-12 cells by participating in lipid metabolism. BEA combated OS damage by increasing phosphatidylcholine, phosphatidylethanolamine, and sphingolipid levels. In the current study, BEA upregulated proteins related to the PI3K/AKT/mTOR pathway, thereby promoting cell survival. These findings support the antioxidant activity of BEA at low concentrations, warranting further research into its pharmacological effects.

Transcriptional Activation of Biosynthetic Gene Clusters in Filamentous Fungi

Filamentous fungi are highly productive cell factories, many of which are industrial producers of enzymes, organic acids, and secondary metabolites. The increasing number of sequenced fungal genomes revealed a vast and unexplored biosynthetic potential in the form of transcriptionally silent secondary metabolite biosynthetic gene clusters (BGCs). Various strategies have been carried out to explore and mine this untapped source of bioactive molecules, and with the advent of synthetic biology, novel applications, and tools have been developed for filamentous fungi. Here we summarize approaches aiming for the expression of endogenous or exogenous natural product BGCs, including synthetic transcription factors, assembly of artificial transcription units, gene cluster refactoring, fungal shuttle vectors, and platform strains.

The Mycotoxin Beauvericin Exhibits Immunostimulatory Effects on Dendritic Cells via Activating the TLR4 Signaling Pathway

Beauvericin (BEA), a mycotoxin of the enniatin family produced by various toxigenic fungi, has been attributed multiple biological activities such as anti-cancer, anti-inflammatory, and anti-microbial functions. However, effects of BEA on dendritic cells remain unknown so far. Here, we identified effects of BEA on murine granulocyte–macrophage colony-stimulating factor (GM-CSF)-cultured bone marrow derived dendritic cells (BMDCs) and the underlying molecular mechanisms. BEA potently activates BMDCs as signified by elevated IL-12 and CD86 expression. Multiplex immunoassays performed on myeloid differentiation primary response 88 (MyD88) and toll/interleukin-1 receptor (TIR) domain containing adaptor inducing interferon beta (TRIF) single or double deficient BMDCs indicate that BEA induces inflammatory cytokine and chemokine production in a MyD88/TRIF dependent manner. Furthermore, we found that BEA was not able to induce IL-12 or IFNβ production in Toll-like receptor 4 (Tlr4)-deficient BMDCs, whereas induction of these cytokines was not compromised in Tlr3/7/9 deficient BMDCs. This suggests that TLR4 might be the functional target of BEA on BMDCs. Consistently, in luciferase reporter assays BEA stimulation significantly promotes NF-κB activation in mTLR4/CD14/MD2 overexpressing but not control HEK-293 cells. RNA-sequencing analyses further confirmed that BEA induces transcriptional changes associated with the TLR4 signaling pathway. Together, these results identify TLR4 as a cellular BEA sensor and define BEA as a potent activator of BMDCs, implying that this compound can be exploited as a promising candidate structure for vaccine adjuvants or cancer immunotherapies.

In silico evidence of beauvericin antiviral activity against SARS-CoV-2

Background

Scientists are still battling severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for the coronavirus 2019 (COVID-19) pandemic so human lives can be saved worldwide. Secondary fungal metabolites are of intense interest due to their broad range of pharmaceutical properties. Beauvericin (BEA) is a secondary metabolite produced by the fungus Beauveria bassiana. Although promising anti-viral activity has previously been reported for BEA, studies investigating its therapeutic potential are limited.

Methods

The objective of this study was to assess the potential usage of BEA as an anti-viral molecule via protein–protein docking approaches using MolSoft.

Results

In-silico results revealed relatively favorable binding energies for BEA to different viral proteins implicated in the vital life stages of this virus. Of particular interest is the capability of BEA to dock to both the main coronavirus protease (Pockets A and B) and spike proteins. These results were validated by molecular dynamic simulation (Gromacs). Several parameters, such as root-mean-square deviation/fluctuation, the radius of gyration, H-bonding, and free binding energy were analyzed. Computational analyses revealed that interaction of BEA with the main protease pockets in addition to the spike glycoprotein remained stable.

Conclusion

Altogether, our results suggest that BEA might be considered as a potential competitive and allosteric agonist inhibitor with therapeutic options for treating COVID-19 pending in vitro and in vivo validation.

The antimicrobial and immunomodulatory effects of Ionophores for the treatment of human infection

Ionophores are a diverse class of synthetic and naturally occurring ion transporter compounds which demonstrate both direct and in-direct antimicrobial properties against a broad panel of bacterial, fungal, viral and parasitic pathogens. In addition, ionophores can regulate the host-immune response during communicable and non-communicable disease states. Although the clinical use of ionophores such as Amphotericin B, Bedaquiline and Ivermectin highlight the utility of ionophores in modern medicine, for many other ionophore compounds issues surrounding toxicity, bioavailability or lack of in vivo efficacy studies have hindered clinical development. The antimicrobial and immunomodulating properties of a range of compounds with characteristics of ionophores remain largely unexplored. As such, ionophores remain a latent therapeutic avenue to address both the global burden of antimicrobial resistance, and the unmet clinical need for new antimicrobial therapies. This review will provide an overview of the broad-spectrum antimicrobial and immunomodulatory properties of ionophores, and their potential uses in clinical medicine for combatting infection.

Beauvericin potentiates the activity of pesticides by neutralizing the ATP-binding cassette transporters in arthropods

Multi-drug resistance is posing major challenges in suppressing the population of pests. Many herbivores develop resistance, causing a prolonged survival after exposure to a previously effective pesticide. Consequently, resistant pests reduce the yield of agricultural production, causing significant economic losses and reducing food security. Therefore, overpowering resistance acquisition of crop pests is a must. The ATP binding cassette transporters (ABC transporters) are considered as the main participants to the pesticide efflux and their neutralization will greatly contribute to potentiate failed treatments. Real-Time PCR analysis of 19 ABC transporter genes belonging to the ABCB, ABCC, ABCG, and ABCH revealed that a broad range of efflux pumps is activated in response to the exposure to pesticides. In this study, we used beauvericin (BEA), a known ABC transporters modulator, to resensitize different strains of Tetranychus urticae after artificial selection for resistance to cyflumetofen, bifenazate, and abamectin. Our results showed that the combinatorial treatment of pesticide (manufacturer's recommended doses) + BEA (sublethal doses: 0.15 mg/L) significantly suppressed the resistant populations of T. urticae when compared to single-drug treatments. Moreover, after selective pressure for 40 generations, the LC₅₀ values were significantly reduced from 36.5, 44.7, and 94.5 (pesticide) to 8.3, 12.5, and 23.4 (pesticide + BEA) for cyflumetofen, bifenazate, and abamectin, respectively. While the downstream targets for BEA are still elusive, we demonstrated hereby that it synergizes with sub-lethal doses of different pesticides and increases their effect by inhibiting ABC transporters. This is the first report to document such combinatorial activity of BEA against higher invertebrates paving the way for its usage in treating refractory cases of resistance to pesticides. Moreover, we demonstrated, for the first time, using in silico techniques, the higher affinity of BEA to ABC transformers subfamilies when compared to xenobiotics; thus, elucidating the pathway of the mycotoxin.

Beauvericin and Enniatins: In Vitro Intestinal Effects

Food and feed contamination by emerging mycotoxins beauvericin and enniatins is a worldwide health problem and a matter of great concern nowadays, and data on their toxicological behavior are still scarce. As ingestion is the major route of exposure to mycotoxins in food and feed, the gastrointestinal tract represents the first barrier encountered by these natural contaminants and the first structure that could be affected by their potential detrimental effects. In order to perform a complete and reliable toxicological evaluation, this fundamental site cannot be disregarded. Several in vitro intestinal models able to recreate the different traits of the intestinal environment have been applied to investigate the various aspects related to the intestinal toxicity of emerging mycotoxins. This review aims to depict an overall and comprehensive representation of the in vitro intestinal effects of beauvericin and enniatins in humans from a species-specific perspective. Moreover, information on the occurrence in food and feed and notions on the regulatory aspects will be provided.

Cyclodepsipeptide Biosynthesis in Hypocreales Fungi and Sequence Divergence of The

Fungi from the Hypocreales order synthesize a range of toxic non-ribosomal cyclic peptides with antimicrobial, insecticidal and cytotoxic activities. Entomopathogenic Beauveria, Isaria and Cordyceps as well as phytopathogenic Fusarium spp. are known producers of beauvericins (BEAs), beauvenniatins (BEAEs) or enniatins (ENNs). The compounds are synthesized by beauvericin/enniatin synthase (BEAS/ESYN1), which shows significant sequence divergence among Hypocreales members. We investigated ENN, BEA and BEAE production among entomopathogenic (Beauveria, Cordyceps, Isaria) and phytopathogenic (Fusarium) fungi; BEA and ENNs were quantified using an LC-MS/MS method. Phylogenetic analysis of partial sequences of putative BEAS/ESYN1 amplicons was also made. Nineteen fungal strains were identified based on sequence analysis of amplified ITS and tef-1α regions. BEA was produced by all investigated fungi, with F. proliferatum and F. concentricum being the most efficient producers. ENNs were synthesized mostly by F. acuminatum, F. avenaceum and C. confragosa. The phylogeny reconstruction suggests that ancestral BEA biosynthesis independently diverged into biosynthesis of other compounds. The divergent positioning of three Fusarium isolates raises the possibility of parallel acquisition of cyclic depsipeptide synthases in ancient complexes within Fusarium genus. Different fungi have independently evolved NRPS genes involved in depsipeptide biosynthesis, with functional adaptation towards biosynthesis of overlapping yet diversified metabolite profiles.

Beauvericin: The beauty and the beast

Beauvericin (BEA) is a natural bioactive compound, with a dual nature. On the one hand, the peculiar characteristics of its molecule confer to BEA interesting properties, such as antibacterial, antiviral, antifungal, antiparasitic, insecticidal and anticarcinogenic activities. On the other hand, it is a natural contaminant of food and feed commodities, and an emerging mycotoxin, but lacks a toxicological risk assessment evaluation for long term exposure. This review aims to provide a global and comprehensive overview on BEA from its biological activities, to its in vivo and in vitro toxicological effects covering the multifaceted nature of this substance.

Selected Fungal Natural Products with Antimicrobial Properties

Fungal natural products and their effects have been known to humankind for hundreds of years. For example, toxic ergot alkaloids produced by filamentous fungi growing on rye poisoned thousands of people and livestock throughout the Middle Ages. However, their later medicinal applications, followed by the discovery of the first class of antibiotics, penicillins and other drugs of fungal origin, such as peptidic natural products, terpenoids or polyketides, have altered the historically negative reputation of fungal "toxins". The development of new antimicrobial drugs is currently a major global challenge, mainly due to antimicrobial resistance phenomena. Therefore, the structures, biosynthesis and antimicrobial activity of selected fungal natural products are described here.

Co-Occurrence of Beauvericin and Enniatins in Edible Vegetable Oil Samples, China

A total of 470 edible vegetable oil samples including peanut, soybean, rapeseed, sesame seed, corn, blend, and others collected from eight provinces of China were analyzed for the concentrations of beauvericin (BEA), enniatin A (ENA), A₁ (ENA₁), B (ENB), and B₁ (ENB₁) by ultraperformance liquid chromatography/electrospray ionization tandem mass spectrometry (UPLC/ESI-MS/MS). Concentrations of BEA, ENB, and ENB₁ (average = 5.59 μg/kg, 5.16 μg/kg, and 4.61 μg/kg) in all positive samples were higher than those for ENA and ENA₁ (average = 0.85 μg/kg and 1.88 μg/kg). Frequencies of BEA and ENNs in all analyzed samples were all higher than 50% with the exception of ENA₁ (36.6%, 172/470). Levels of BEA and ENNs in all analyzed samples varied based on their sample types and geographical distributions (Kruskal–Wallis test, p < 0.05). The soybean and peanut oil samples were found to be more easily contaminated by BEA and ENNs than other oil samples. Concentrations of BEA and ENNs in samples obtained from Heilongjiang, Shandong and Guizhou were higher than those found in samples from other provinces. Besides, frequencies of mycotoxin co-contaminations were high and their co-contamination types also varied by oil types. BEA-ENA-ENA₁-ENB-ENB₁ was the most commonly found toxin combination type, almost in one third of the analyzed samples (30%, 141/470). Overall, these results indicate that co-occurrence of BEA and ENNs in analyzed Chinese edible vegetable oil samples is highly common, and it is vital to monitor them, both simultaneously and on a widespread level.

Co-culture of the fungus Fusarium tricinctum with Streptomyces lividans induces production of cryptic naphthoquinone dimers

Co-cultivation of the endophytic fungus Fusarium tricinctum with Streptomyces lividans on solid rice medium led to the production of four new naphthoquinone dimers, fusatricinones A–D (1–4), and a new lateropyrone derivative, dihydrolateropyrone (5), that were not detected in axenic fungal controls. In addition, four known cryptic compounds, zearalenone (7), (−)-citreoisocoumarin (8), macrocarpon C (9) and 7-hydroxy-2-(2-hydroxypropyl)-5-methylchromone (10), that were likewise undetectable in extracts from fungal controls, were obtained from the co-culture extracts. The known antibiotically active compound lateropyrone (6), the depsipeptides enniatins B (11), B1 (12) and A1 (13), and the lipopeptide fusaristatin A (14), that were present in axenic fungal controls and in co-culture extracts, were upregulated in the latter. The structures of the new compounds were elucidated by 1D and 2D NMR spectra as well as by HRESIMS data. The relative and absolute configuration of dihydrolateropyrone (5) was elucidated by TDDFT-ECD calculations.

Naphthoquinone dimers from co-culture of Fusarium tricinctum with Streptomyces lividans.

A Review on the Synthesis and Bioactivity Aspects of Beauvericin, a Fusarium Mycotoxin

Beauvericin (BEA) is an emerging Fusarium mycotoxin that contaminates food and feeds globally. BEA biosynthesis is rapidly catalyzed by BEA synthetase through a nonribosomal, thiol-templated mechanism. This mycotoxin has cytotoxicity and is capable of increasing oxidative stress to induce cell apoptosis. Recently, large evidence further shows that this mycotoxin has a variety of biological activities and is being considered a potential candidate for medicinal and pesticide research. It is noteworthy that BEA is a potential anticancer agent since it can increase the intracellular Ca²⁺ levels and induce the cancer cell death through oxidative stress and apoptosis. BEA has exhibited effective antibacterial activities against both pathogenic Gram-positive and Gram-negative bacteria. Importantly, BEA exhibits an effective capacity to inhibit the human immunodeficiency virus type-1 integrase. Moreover, BEA can simultaneously target drug resistance and morphogenesis which provides a promising strategy to combat life-threatening fungal infections. Thus, in this review, the synthesis and the biological activities of BEA, as well as, the underlying mechanisms, are fully analyzed. The risk assessment of BEA in food and feed are also discussed. We hope this review will help to further understand the biological activities of BEA and cast some new light on drug discovery.

In vitro mechanisms of Beauvericin toxicity: A review

Beauvericin (BEA) is a mycotoxin produced by many species of fungus Fusarium and by Beauveria bassiana; BEA is a natural contaminant of cereals and cereals based products and possesses a wide variety of biological properties. The mechanism of action seems to be related to its ionophoric activity, that increases ion permeability in biological membranes. As a consequence, BEA causes cytotoxicity in several cell lines and is capable to produce oxidative stress at molecular level. Moreover, BEA is genotoxic (produces DNA fragmentation, chromosomal aberrations and micronucleus) and causes apoptosis with the involvement of mitochondrial pathway. However, several antioxidant mechanisms protect cells against oxidative stress produced by BEA. Despite its strong cytotoxicity, no risk assessment have been still carried out by authorities due to a lack of toxicity data, so research on BEA toxicological impact is still going on. This review reports information available regarding BEA mechanistic toxicology with the aim of updating information regarding last researches on this mycotoxin.

Enniatin and Beauvericin Biosynthesis in Fusarium Species: Production Profiles and Structural Determinant Prediction

Members of the fungal genus Fusarium can produce numerous secondary metabolites, including the nonribosomal mycotoxins beauvericin (BEA) and enniatins (ENNs). Both mycotoxins are synthesized by the multifunctional enzyme enniatin synthetase (ESYN1) that contains both peptide synthetase and S-adenosyl-l-methionine-dependent N-methyltransferase activities. Several Fusarium species can produce ENNs, BEA or both, but the mechanism(s) enabling these differential metabolic profiles is unknown. In this study, we analyzed the primary structure of ESYN1 by sequencing esyn1 transcripts from different Fusarium species. We measured ENNs and BEA production by ultra-performance liquid chromatography coupled with photodiode array and Acquity QDa mass detector (UPLC-PDA-QDa) analyses. We predicted protein structures, compared the predictions by multivariate analysis methods and found a striking correlation between BEA/ENN-producing profiles and ESYN1 three-dimensional structures. Structural differences in the β strand's Asn789-Ala793 and His797-Asp802 portions of the amino acid adenylation domain can be used to distinguish BEA/ENN-producing Fusarium isolates from those that produce only ENN.

Bioactive endophytic fungi isolated from Caesalpinia echinata Lam. (Brazilwood) and identification of beauvericin as a trypanocidal metabolite from Fusarium sp

Aiming to identify new sources of bioactive secondary metabolites, we isolated 82 endophytic fungi from stems and barks of the native Brazilian tree Caesalpinia echinata Lam. (Fabaceae). We tested their ethyl acetate extracts in several in vitro assays. The organic extracts from three isolates showed antibacterial activity against Staphylococcus aureus and Escherichia coli [minimal inhibitory concentration (MIC) 32-64 μg/mL]. One isolate inhibited the growth of Salmonella typhimurium (MIC 64 μg/mL) and two isolates inhibited the growth of Klebsiella oxytoca (MIC 64 μg/mL), Candida albicans and Candida tropicalis (MIC 64-128 μg/mL). Fourteen extracts at a concentration of 20 μg/mL showed antitumour activities against human breast cancer and human renal cancer cells, while two isolates showed anti-tumour activities against human melanoma cancer cells. Six extracts were able to reduce the proliferation of human peripheral blood mononuclear cells, indicating some degree of selective toxicity. Four isolates were able to inhibit Leishmania (Leishmania) amazonensis and one isolate inhibited Trypanosoma cruzi by at least 40% at 20 μg/mL. The trypanocidal extract obtained from Fusarium sp. [KF611679] culture was subjected to bioguided fractionation, which revealed beauvericin as the compound responsible for the observed toxicity of Fusarium sp. to T. cruzi. This depsipeptide showed a half maximal inhibitory concentration of 1.9 μg/mL (2.43 μM) in a T. cruzi cellular culture assay.

Beauveria bassiana: Biocontrol Beyond Lepidopteran Pests

Beauveria bassiana has been extensively employed since the last century for biocontrol of lepidopteran pests. B. bassiana has also been explored for diverse functions including bioremediation of toxic industrial effluents and heavy-metal polluted soils. Investigations on multifarious applications of chemically diverse secondary metabolites of this entomopathogenic fungus offer promising implications in pharmaceutical and agricultural sectors. In addition, the development of eco-friendly bioremediation strategies using abiotic stress-tolerant strains of B. bassiana will contribute to maintain the sustainability of agroecosystem.

Synergistic effect of a novel cyclic pentadepsipeptide, neoN-methylsansalvamide, and paclitaxel on human multidrug resistance cancer cell lines

NeoN-methylsansalvamide is a novel low-molecular-weight cyclic pentadepsipeptide that exerts cytotoxic effects on various human cancer cell lines. Its structural analysis using liquid chromatography mass/mass spectrometry showed the cyclic structure sequence -phenylalanine-leucine-valine-N-methylleucine-leucic acid-. The intrinsic cytotoxic and multidrug resistance reversal effects of neoN-methylsansalvamide were evaluated on the human cancer cell lines MES-SA and HCT15 as well as on their multidrug resistance sublines (MES-SA/DX5 and HCT15/CL05, respectively) using the sulforhodamine B assay. The EC50 values of paclitaxel for MES-SA, HCT15, and for the multidrug resistance sublines MES-SA/DX5 and HCT15/CL05 were 1.00±0.20, 0.85±0.63, 10.00±0.53, and >1000 nmol/l, respectively. However, the EC50 values for paclitaxel including 3 μmol/l neoN-methylsansalvamide for MES-SA/DX5, HCT15, and HCT15/CL02 were 1.58±0.12, 0.10±0.02, and 288.40±21.02 nmol/l, respectively. The in-vitro multidrug resistance reversal activity of neoN-methylsansalvamide was similar to that of the control verapamil. These finding suggests that a novel cyclic pentadepsipeptide, neoN-methylsansalvamide, is effective in reversing multidrug resistance in vitro, and this activity may be a major applicable biological function of this compound.

Structural analysis of a new cytotoxic demethylated analogue of neo-N-methylsansalvamide with a different peptide sequence produced by Fusarium solani isolated from potato

A novel cytotoxic cyclic pentadepsipeptide, neosansalvamide, was produced by Fusarium solani KCCM90040 isolated from Fusarium -contaminated potato in Korea. The molecular formula of neosansalvamide was analyzed as C₃₂H₅₀N₄O₆ by electrospray ionization tandem mass spectrometry and combined structural analysis. The one- and two-dimensional nuclear magnetic resonance and absolute configuration of amino acid spectral data allowed for the resolution of cyclic five subunits linked in the following order: (S)-leucic acid, two L-leucine, L-valine, and L-phenylalanine, and this sequence shows a molecular structure as a new demethylated analogue of neo-N-methylsansalvamide but having a different peptide sequence. The cytotoxic effects of neosansalvamide were investigated by sulforhodamine B bioassay on four human cancer cell lines. The IC₅₀ value of neosansalvamide required to inhibit cell growth in vitro by 50% for A549 (lung cancer), SK-OV-3 (ovarian cancer), SK-MEL-2 (skin melanoma), and MES-SA (uterine sarcoma) cell lines were 11.70 ± 0.55, 10.38 ± 0.64, 13.99 ± 1.32, and 11.75 ± 0.13 μM, respectively (mean ± standard error).

Beauvericin, a bioactive compound produced by fungi: a short review

Beauvericin is a cyclic hexadepsipeptide mycotoxin, which has insecticidal, antimicrobial, antiviral and cytotoxic activities. It is a potential agent for pesticides and medicines. This paper reviews the bioactivity, fermentation and biosynthesis of the fungal product beauvericin.

Beauvericin production by the Lepidoptera pathogenic fungus Isaria tenuipes: Analysis of natural specimens, synnemata from cultivation, and mycelia from liquid-media fermentation

Beauvericin was analyzed in three forms of the Lepidoptra pathogenic fungus Isaria tenuipes (4 isolates): (a) natural specimen, (b) cultivated synnemata on rice media, and (c) mycelia from fermentation in liquid media. Beauvericin was detected in very low amounts in all tested natural specimens. Synnemata on rice contained much higher concentrations of beauvericin than the corresponding natural materials, although the concentrations were lower than mycelia from liquid fermentation. The results casted a caution that beauvericin concentration should be carefully checked, as a possible toxic constituent, upon mass production of a selected strain of Isaria tenuipes for health food purposes.

Beauvericin induced erythrocyte cell membrane scrambling

Beauvericin is a mycotoxin with antiviral, antibacterial, nematicidal, insecticidal, cytotoxic, and apoptotic activity. Similar to nucleated cells erythrocytes may undergo suicidal death or eryptosis, which is characterized by cell shrinkage and phosphatidylserine exposure at the erythrocyte surface. Eryptosis may be triggered by energy depletion leading to increase of cytosolic Ca²+ activity. The present study thus explored whether beauvericin is able to trigger eryptosis and influence eryptosis following energy depletion. Cell membrane scrambling was estimated from binding of annexin V to phosphatidylserine at the erythrocyte surface, cell volume from forward scatter in FACS analysis, cytosolic Ca²+ concentration from Fluo3 fluorescence, cytosolic ATP concentration from a luciferase-assay and ion channel activity with whole cell patch clamp. Exposure to beauvericin (≥ 5 μM) significantly decreased erythrocyte ATP concentration and increased cytosolic Ca²+ concentration as well as annexin V-binding. The effect of beauvericin on annexin V binding was significantly blunted by removal of extracellular Ca²+. Glucose depletion (48 h) was followed by, increase of Fluo3 fluorescence, decrease of forward scatter and increase of annexin V-binding. Beauvericin (≥ 1 μM) augmented the effect of glucose withdrawal on Fluo3 fluorescence and annexin V-binding, but significantly blunted the effect of glucose withdrawal on forward scatter, an effect paralleled by inhibition of Ca²+ activated K+ channels. The present observations disclose novel effects of beauvericin, i.e. stimulation of Ca²+ entry with subsequent cell membrane scrambling and inhibition of Ca²+ activated K+ channels with blunting of cell shrinkage.

Beauvericin and enniatin: emerging toxins and/or remedies?

Beauvericin (BEA) and enniatins (ENN) are emerging Fusarium mycotoxins that are known to contaminate food and feed. BEA- and ENN-mediated cytotoxicity towards various mammalian and cancer cell lines is only partly understood yet and engages several cellular targets and molecular mechanisms. Thus, the channel forming ability of BEA and ENN selectively directs a flux of cations – particularly calcium – into the cell. The resulting increased intracellular calcium levels might be at least in part responsible for their cytotoxicity. Additionally, BEA and ENN activate programmed cell death via the internal mitochondrial pathway (release of cytochrome c, activation of pro-apoptotic proteins such as Bax and activation of caspases). Several cellular signalling pathways and regulators are influenced by these fusariotoxins including MAPK, NF-κB and p53. The in vitro cytotoxicity implicates that these compounds could be potentially used as cancer therapeutics. However, considering their high prevalence in grains destined for consumption, also potential systemic toxicity towards humans and animals has to be considered. Interestingly, the few studies that have addressed this issue in animals so far predominantly reported minor effects at least as far as acute toxicity is concerned. However, consequences especially of chronic exposure but also at pharmacologically active doses in humans/animals have not been explored in detail. Nevertheless, both compounds exhibit interesting pharmacological characteristics (as they are cytotoxic especially to cancer cells, inhibit drug efflux pumps, are non-mutagenic, inhibit bone resorption) which suggest them as potential drug candidates to fight disseminated cancer. Thus, detailed studies on the consequences of chronic and bolus BEA and ENN exposure are eagerly needed.