Project description:Four new derivatives of ketoconazole (Ke) were synthesized: diphenylphosphane (KeP), and phosphane chalcogenides: oxide (KeOP), sulphide (KeSP) and selenide (KeSeP). These compounds proved to be promising antifungal compounds towards Saccharomyces cerevisiae and Candida albicans, especially in synergy with fluconazole. Simulations of docking to the cytochrome P450 14α-demethylase (azoles' primary molecular target) proved that the new Ke derivatives are capable of inhibiting this enzyme by binding to the active site. Cytotoxicity towards hACSs (human adipose-derived stromal cells) of the individual compounds was studied and the IC50 values were higher than the MIC50 for C. albicans and S. cerevisiae. KeP and KeOP increased the level of the p21 gene transcript but did not change the level of p53 gene transcript, a major regulator of apoptosis, and decreased the mitochondrial membrane potential. Taken together, the results advocate that the new ketoconazole derivatives have a similar mechanism of action and block the lanosterol 14α-demethylase and thus inhibit the production of ergosterol in C. albicans membranes.
Project description:Therapeutic options to treat invasive fungal infections are still limited. This makes the development of novel antifungal agents highly desirable. Naturally occurring antifungal peptides represent valid candidates, since they are not harmful for human cells and are endowed with a wide range of activities and their mechanism of action is different from that of conventional antifungal drugs. Here, we characterized for the first time the antifungal properties of novel peptides identified in human apolipoprotein B. ApoB-derived peptides, here named r(P)ApoBLPro, r(P)ApoBLAla and r(P)ApoBSPro, were found to have significant fungicidal activity towards Candida albicans (C. albicans) cells. Peptides were also found to be able to slow down metabolic activity of Aspergillus niger (A. niger) spores. In addition, experiments were carried out to clarify the mechanism of fungicidal activity of ApoB-derived peptides. Peptides immediately interacted with C. albicans cell surfaces, as indicated by fluorescence live cell imaging analyses, and induced severe membrane damage, as indicated by propidium iodide uptake induced upon treatment of C. albicans cells with ApoB-derived peptides. ApoB-derived peptides were also tested on A. niger swollen spores, initial hyphae and branched mycelium. The effects of peptides were found to be more severe on swollen spores and initial hyphae compared to mycelium. Fluorescence live cell imaging analyses confirmed peptide internalization into swollen spores with a consequent accumulation into hyphae. Altogether, these findings open interesting perspectives to the application of ApoB-derived peptides as effective antifungal agents. KEY POINTS: Human cryptides identified in ApoB are effective antifungal agents. ApoB-derived cryptides exert fungicidal effects towards C. albicans cells. ApoB-derived cryptides affect different stages of growth of A. niger. Graphical abstract.
Project description:The high incidence of fungal pathogens has become a global issue for crop protection. A promising strategy to control fungal plant infections is based on the use of nature-inspired compounds. The cytochrome bc1 complex is an essential component of the cellular respiratory chain and is one of the most important fungicidal targets. Natural products have played a crucial role in the discovery of cytochrome bc1 inhibitors, as proven by the development of strobilurins, one of the most important classes of crop-protection agents, over the past two decades. In this review, we summarize advances in the exploration of natural product scaffolds for the design and development of new bc1 complex inhibitors. Particular emphasis is given to molecular modeling-based approaches and structure-activity relationship (SAR) studies performed to improve the stability and increase the potency of natural precursors. The collected results highlight the versatility of natural compounds and provide an insight into the potential development of nature-inspired derivatives as antifungal agents.
Project description:Since its first report in December 2019, the novel coronavirus virus, SARS-CoV-2, has caused an unprecedented global health crisis and economic loss imposing a tremendous burden on the worldwide finance, healthcare system, and even daily life. Even with the introduction of different preventive vaccines, there is still a dire need for effective antiviral therapeutics. Nature has been considered as the historical trove of drug discovery and development, particularly in cases of worldwide crises. Herein, a comprehensive in silico investigation of a highly focused chemical library of 34 pederin-structurally related marine compounds, belonging to four polyketides families, was initiated against the SARS-CoV-2 main protease, Mpro, being the key replicating element of the virus and main target in many drugs development programs. Two of the most potent SARS-CoV-2 Mpro co-crystallized inhibitors, O6K and N3, were added to the tested database as reference standards. Through molecular docking simulation, promising compounds including Pederin (1), Dihydro-onnamide A (11), Onnamide C (14), Pseudo-onnamide A (17), and Theopederin G (29) have been identified from different families based on their superior ligand-protein energies and relevant binding profiles with the key Mpro pocket residues. Thermodynamic behaviors of the identified compounds were investigated through 200 ns all-atom molecular dynamics simulation illustrating their significant stability and pocket accommodation. Furthermore, structural activity preferentiality was identified for the pederin-based marine compounds highlighting the importance of the terminal guanidine and cyclic hemiacetal linker, and the length of the sidechain. Our findings highlight the challenges of targeting SARS-CoV-2 Mpro as well as recommending further in vitro and in vivo studies regarding the examined marine products either alone or in combination paving the way for promising lead molecules.
Project description:Piperine is a natural alkaloid with a wide range of biological functions. Natural phenolic compounds existed in many essential oils (EOs) are plant-derived aroma compounds with broad range of biological activities, however, their actions are slow, and they are typically unstable to light or heat, difficult to extract and so on. In order to find high-potential fungicides derived from piperine, a series of piperine-directed essential oil derivatives were designed and synthesized. The structures of all molecules were confirmed by satisfied spectral data, including 1H NMR, 13C NMR and ESIMS. The target compounds were screened for their potential fungicidal activities against six species of plant pathogen fungi, including Rhizoctonia solani, Fusarium graminearum, Phomopsis adianticola, Alternaria tenuis Nees, Phytophthora capsici and Gloeosporium theae-sinensis. Some of target compounds exhibited moderate and broad-spectrum activity against tested fungi compared to the parental piperine. Further studies have shown that some different concentrations of compounds have significant inhibitory activity against Alternaria tenuis Nees and Phytophthora capsici compared to commercial carbendazim, and compound 2b exhibited particularly significant broad-spectrum fungicidal activity.
Project description:A novel series of 4,6-disubstituted s-triazin-2-yl amino acid derivatives was prepared and characterized. Most of them showed antifungal activity against Candida albicans compared to clotrimazole (standard drug). Compounds bearing aniline derivatives, piperidine and glycine on the triazine core showed the highest inhibition zones at concentrations of 50, 100, 200, and 300 μg per disc. In addition, docking studies revealed that all the compounds accommodated well in the active site residues of N-myristoltransferase (NMT) and exhibited complementarity, which explains the observed antifungal activity. Interestingly, none of these compounds showed antibacterial activity.
Project description:In the present study, we designed and synthesized thiolated VK3 analogs (VK3a-g) along with an extensive antimicrobial study. After the evaluation of the antibacterial and antifungal activity against various bacterial and fungal strains, we presented an initial structure-activity relationship study on these VK3 analogs. In particular, four thiolated VK3 analogs exhibited superior biological potency against some Gram-positive bacterial strains, including Staphylococcus aureus (ATCC® 29213) and Enterococcus faecalis (ATCC® 29212). Next, all thiolated VK3 analogs were evaluated for their potential of cell growth inhibition on the NCI-60 cancer cell lines panel. This screening underlined that the thiolated VK3 analogs have no visible cytotoxicity on different cancer cell lines. The selected two thiolated VK3 analogs (VK3a and VK3b), having minimal hemolytic activity, which also have the lowest MIC values on S. aureus and E. faecalis, were further evaluated for their inhibition capacities on biofilm formation after evaluating their potential in vitro antimicrobial activity against each of the 20 clinically obtained resistant strains of Staphylococcus aureus. VK3b showed excellent antimicrobial activity against clinically resistant S. aureus isolates. Furthermore, the tested molecules showed nearly two log10 reduction in the viable cell count at six hours according to the time kill curve studies. Although these molecules decreased biofilm attachment about 50%, when sub-MIC concentrations were used these molecules increased the percentage of biofilm formation. The molecular docking of VK3a and VK3b in S. aureus thymidylate kinase was conducted in order to predict their molecular interactions. VK3a and VK3b exhibited excellent lead-likeness properties and pharmacokinetic profiles that qualify them for further optimization and development. In conclusion, since investigating efficient novel antimicrobial molecules is quite difficult, these studies are of high importance, especially in the present era of antimicrobial resistance.
Project description:Molecular glues are an intriguing therapeutic modality that harness small molecules to induce interactions between proteins that typically do not interact. However, such molecules are rare and have been discovered fortuitously, thus limiting their potential as a general strategy for therapeutic intervention. We postulated that natural products bearing one or more electrophilic sites may be an unexplored source of new molecular glues, potentially acting through multicovalent attachment. Using chemoproteomic platforms, we show that members of the manumycin family of polyketides, which bear multiple potentially reactive sites, target C374 of the putative E3 ligase UBR7 in breast cancer cells, and engage in molecular glue interactions with the neosubstrate tumor-suppressor TP53, leading to p53 transcriptional activation and cell death. Our results reveal an anticancer mechanism of this natural product family, and highlight the potential for combining chemoproteomics and multicovalent natural products for the discovery of new molecular glues.
Project description:Rhamnolipids (RLs) and fengycins (FGs) are amphiphilic lipid compounds from bacteria secretomes proposed to replace synthetic pesticides for crop protection. They both display plant defense triggering properties and direct antimicrobial activities. In particular, they have well reported antifungal effects against phytopathogenic fungi. RLs and FGs are considered to act through a direct interaction with membrane lipids and a destabilization of microorganism plasma membrane, thereby limiting the risk of resistance emergence. The main objective of this work was to gain insights in the antimycelial mode of action of these metabolites to promote them as environment and human health friendly biocontrol solutions. Their biocidal effects were studied on two Sclerotiniaceae fungi responsible for diseases in numerous plant species worldwide. We show here that different strains of Botrytis cinerea and Sclerotinia sclerotiorum have opposite sensitivities to RLs and FGs on plate experiments. Overall, B. cinerea is more sensitive to FGs while S. sclerotiorum is more sensitive to RLs. Electron microscopy observations demonstrated that RLs induce mycelial destructuring by asperities emergence and hyphal fusions whereas FGs promote swelling and formation of vesicle-like structures due to vacuole fusions and autophagy. Permeability studies, phosphatidylserine externalization and reactive oxygen species production assessments showed a programmed cell death triggering by RLs at medium concentrations (until 50 μg mL-1) and necrosis characteristics at higher concentration. Programmed cell death was always observed on hyphae treated with FGs. Quantifications of mycelial ergosterol content indicated that a higher ergosterol rate in S. sclerotiorum correlates with increasing sensitivity to RLs. Oppositely, a lower ergosterol rate in B. cinerea correlates with increasing sensitivity to FGs, which was confirmed by ergosterol biosynthesis inhibition with tebuconazole. This gain of knowledge will help to better understand the mode of action of RLs and FGs to fight specific plant fungal diseases.