Isolation, characterization and antifungal docking studies of wortmannin isolated from Penicillium radicum

Fascinating Furanosteroids and Their Pharmacological Profile

This review article delves into the realm of furanosteroids and related isoprenoid lipids derived from diverse terrestrial and marine sources, exploring their wide array of biological activities and potential pharmacological applications. Fungi, fungal endophytes, plants, and various marine organisms, including sponges, corals, molluscs, and other invertebrates, have proven to be abundant reservoirs of these compounds. The biological activities exhibited by furanosteroids and related lipids encompass anticancer, cytotoxic effects against various cancer cell lines, antiviral, and antifungal effects. Notably, the discovery of exceptional compounds such as nakiterpiosin, malabaricol, dysideasterols, and cortistatins has revealed their potent anti-tuberculosis, antibacterial, and anti-hepatitis C attributes. These compounds also exhibit activity in inhibiting protein kinase C, phospholipase A2, and eliciting cytotoxicity against cancer cells. This comprehensive study emphasizes the significance of furanosteroids and related lipids as valuable natural products with promising therapeutic potential. The remarkable biodiversity found in both terrestrial and marine ecosystems offers an extensive resource for unearthing novel biologically active compounds, paving the way for future drug development and advancements in biomedical research. This review presents a compilation of data obtained from various studies conducted by different authors who employed the PASS software 9.1 to evaluate the biological activity of natural furanosteroids and compounds closely related to them. The utilization of the PASS software in this context offers valuable advantages, such as screening large chemical libraries, identifying compounds for subsequent experimental investigations, and gaining insights into potential biological activities based on their structural features. Nevertheless, it is crucial to emphasize that experimental validation remains indispensable for confirming the predicted activities.

Bioactive and unusual steroids from Penicillium fungi

Penicillium fungi are represented by various species and can be found worldwide and thrive in a range of environments, such as in the soil, air, and indoors, and in marine environments, as well as food products. Chemical investigation of species of this genus has led to the discovery of compounds from several structural classes with varied bioactivities. As an example, this genus has been a source of bioactive and structurally unusual steroids. The scope of this short review is to cover specialized metabolites of the steroid class and the cytotoxic, antimicrobial, anti-inflammatory as well as phytotoxic activities of these compounds. Other steroids that possess unusual structures, with significant bioactivity yet to determined, will also be discussed to further demonstrate the structural diversity of this compound class from Penicillium fungi, and hopefully inspire the further exploration of such compounds to uncover their activity.

Systematic analysis to identify novel disease indications and plausible potential chemical leads of glutamate ionotropic receptor NMDA type subunit 1, GRIN1

Schizophrenia is a mental illness affecting the normal lifestyle of adults and early adolescents incurring major symptoms as jumbled speech, involvement in everyday activities eventually got reduced, patients always struggle with attention and memory, reason being both the genetic and environmental factors responsible for altered brain chemistry and structure, resulting in schizophrenia and associated orphan diseases. The network biology describes the interactions among genes/proteins encoding molecular mechanisms of biological processes, development, and diseases. Besides, all the molecular networks, protein-protein Interaction Networks have been significant in distinguishing the pathogenesis of diseases and thereby drug discovery. The present meta-analysis prioritizes novel disease indications viz. rare and orphan diseases associated with target Glutamate Ionotropic Receptor NMDA Type Subunit 1, GRIN1 using text mining knowledge-based tools. Furthermore, ZINC database was virtually screened, and binding conformation of selected compounds was performed and resulted in the identification of Narciclasine (ZINC04097652) and Alvespimycin (ZINC73138787) as potential inhibitors. Furthermore, docked complexes were subjected to MD simulation studies which suggests that the identified leads could be a better potential drug to recuperate schizophrenia.

Role of Protein Glycosylation in Interactions of Medically Relevant Fungi with the Host

Protein glycosylation is a highly conserved post-translational modification among organisms. It plays fundamental roles in many biological processes, ranging from protein trafficking and cell adhesion to host–pathogen interactions. According to the amino acid side chain atoms to which glycans are linked, protein glycosylation can be divided into two major categories: N-glycosylation and O-glycosylation. However, there are other types of modifications such as the addition of GPI to the C-terminal end of the protein. Besides the importance of glycoproteins in biological functions, they are a major component of the fungal cell wall and plasma membrane and contribute to pathogenicity, virulence, and recognition by the host immunity. Given that this structure is absent in host mammalian cells, it stands as an attractive target for developing selective compounds for the treatment of fungal infections. This review focuses on describing the relationship between protein glycosylation and the host–immune interaction in medically relevant fungal species.

Elucidation of antifungal and aflatoxin B1 inhibitory mode of action of Eugenia caryophyllata L. essential oil loaded chitosan nanomatrix against Aspergillus flavus

The present study investigated the novel antifungal, and anti-aflatoxin B₁ mechanism of Eugenia caryophyllata L. essential oil (ECEO) loaded chitosan nanomatrix against the toxigenic strain of A. flavus (AFLV-DK-02). Phytochemical profiling of ECEO was done by GC-MS which revealed eugenol (73.6%) as the primary bioactive compound. ECEO was encapsulated inside the chitosan nanomatrix (ECEO-Np) and characterized using SEM, AFM, FTIR and XRD analysis. The ECEO-Np exhibited enhance antifungal (0.25 μL/mL) and anti-aflatoxin B₁ inhibitory activity (0.15 μL/mL) than ECEO. Antifungal and antiaflatoxin B₁ inhibitory activity was found to be related with impairment in the biological functioning of the plasma membrane (ergosterol synthesis, leakage of membrane ions, UV light (260, 280 nm) absorbing material, dead cell by propidium iodide assay, mitochondrial membrane potential (MMP), methylglyoxal and inhibition in essential carbon substrate utilization). ECEO-Np exhibited remarkable free radical scavenging activity with IC₅₀ value of 0.002 μL/mL. ECEO-Np effectively preserves the sensory characteristics of exposed maize crop seed up to six months of storage and shows considerable safety profile (non-toxic, non-mutagenic, non-hepatotoxic, non-carcinogenic, non-tumorigenic and biodegradable) using computational ADMET (absorption, distribution, metabolism, excretion, and toxicity) analysis.

Anticancer Drug Discovery from Microbial Sources: The Unique Mangrove Streptomycetes

Worldwide cancer incidence and mortality have always been a concern to the community. The cancer mortality rate has generally declined over the years; however, there is still an increased mortality rate in poorer countries that receives considerable attention from healthcare professionals. This suggested the importance of the prompt detection, effective treatment, and prevention strategies. The genus Streptomyces has been documented as a prolific producer of biologically active secondary metabolites. Streptomycetes from mangrove environments attract researchers' attention due to their ability to synthesize diverse, interesting bioactive metabolites. The present review highlights research on mangrove-derived streptomycetes and the production of anticancer-related compounds from these microorganisms. Research studies conducted between 2008 and 2019, specifically mentioning the isolation of streptomycetes from mangrove areas and described the successful purification of compound(s) or generation of crude extracts with cytotoxic activity against human cancer cell lines, were compiled in this review. It is anticipated that there will be an increase in prospects for mangrove-derived streptomycetes as one of the natural resources for the isolation of chemotherapeutic agents.

Study of the Binding Interaction between Wortmannin and Calf Thymus DNA: Multispectroscopic and Molecular Docking Studies

INTRODUCTION

Wortmannin (WTN) is a steroid metabolite that inhibits phosphatidylinositol 3-kinase and other signaling pathways. Structurally, the WTN consists of a cyclopentanophenanthrene-like structure with several oxygen-rich moieties which have the potential to interact with deoxyribonucleic acid (DNA) molecules.

METHODS

We aim to evaluate the WTN and calf thymus DNA (ct-DNA) interaction with molecular docking using the AutoDock 4.2 software. UV and fluorescence spectroscopy and viscosity techniques were performed to confirm the in silico analysis.

RESULTS

Molecular docking showed that the WTN interacted with ct-DNA via hydrogen bonds at guanine-rich sequences. The number of hydrogen bonds between the WTN and DNA was 1-2 bonds (average 1.2) per WTN molecule. The in silico binding constant was 2 × 103 M-1. UV spectroscopy showed that the WTN induced a hyperchromic feature without wavelength shifting. The WTN and DNA interaction led to quenching of DNA-emitted fluorescence. The different concentrations of WTN had no effect on DNA viscosity. Taken together, our results demonstrated WTN interacts with DNA in the nonintercalating mode, which is considered as a new mechanism of action.

CONCLUSION

These results suggest that the WTN may exert its biological effects, at least in part, via interaction with DNA.

Comparative assessment of the therapeutic drug targets of C. botulinum ATCC 3502 and C. difficile str. 630 using in silico subtractive proteomics approach

Growing antimicrobial resistance of the pathogens against multiple drugs posed a serious threat to the human health worldwide. This fueled the need of identifying the novel therapeutic targets that can be used for developing new class of the drugs. Recently, there is a substantial rise in the rate of Clostridium infections as well as in the emergence of virulent and antibiotic resistant strains. Hence, there is an urgent need for the identification of potential therapeutic targets and the development of new drugs for the treatment and prevention of Clostridium infections. In the present study, a combinatorial approach involving systems biology and comparative genomics strategy was tested against Clostridium botulinum ATCC 3502 and Clostridium difficile str. 630 pathogens, to render potential therapeutic target at qualitative and quantitative level. This resulted in the identification of five common (present in both the pathogens, 34 in C. botulinum ATCC 3502 and 42 in C. difficile str. 630) drug targets followed by virtual screening-based identification of potential inhibitors employing molecular docking and molecular dynamics simulations. The identified targets will provide a solid platform for the designing of novel wide-spectrum lead compounds capable of inhibiting their catalytic activities against multidrug-resistant Clostridium in the near future.

Isolation, Purification, and Characterization of Heparinase from Streptomyces variabilis MTCC 12266

Arterial/venous thrombosis is the major cardiovascular disorder accountable for substantial mortality; and the current demand for antithrombotic agents is extensive. Heparinases depolymerize unfractionated heparin (UFH) for the production of low molecular-weight heparins (LMWHs; used as anticoagulants against thrombosis). A microbial strain of Streptomyces sp. showing antithrombotic activity was isolated from the soil sample collected from north India. The strain was characterized by using 16S rRNA homology technique and identified as Streptomyces variabilis MTCC 12266 capable of producing heparinase enzyme. This is the very first communication reporting Streptomyces genus as the producer of heparinase. It was observed that the production of intracellular heparinase was [63.8 U/mg protein (specific activity)] 1.58 folds higher compared to extracellular heparinase [40.28 U/mg protein]. DEAE-Sephadex A-50 column followed by Sepharose-6B column purification of the crude protein resulted 19.18 folds purified heparinase. SDS-PAGE analysis of heparinase resulted an estimated molecular-weight of 42 kDa. It was also found that intracellular heparinase has the ability to depolymerize heparin to generate LMWHs. Further studies related to the mechanistic action, structural details, and genomics involved in heparinase production from Streptomyces variabilis are warranted for large scale production/purification optimization of heparinase for antithrombotic applications.

Drug repurposing against arabinosyl transferase (EmbC) of Mycobacterium tuberculosis: Essential dynamics and free energy minima based binding mechanics analysis

Arabinosyl tranferases (embA, embB, embC) are the key enzymes responsible for biogenesis of arabinan domain of arabinogalactan (AG) and lipoarabinomannan (LAM), two major heteropolysaccharide constituents of the peculiar mycobacterial cell envelope. EmbC is predominantly responsible for LAM synthesis and has been commonly associated with Ethambutol resistance. We have screened the FDA library against EmbC to reposition a drug better than Ethambutol with higher binding affinity to Embc. High throughput virtual screening followed by extra precision docking using Glide gave two best leads i.e. Terlipressin and Amikacin with docking score of -11.39 kcal/mol and -10.71 kcal/mol, respectively. Binding mechanics of the selected drugs was elucidated through long range molecular dynamics simulations (100 ns) using binding free energy rescoring, essential dynamics and free energy minima based approaches, thus revealing the most stable binding modes of Terlipressin with EmbC. Our study establishes the EmbC binding potential of the repurposed drugs Terlipressin and Amikacin.

Inhibition of C298S mutant of human aldose reductase for antidiabetic applications: Evidence from in silico elementary mode analysis of biological network model

Human aldose reductase (hAR) is the key enzyme in sorbitol pathway of glucose utilization and is implicated in the etiology of secondary complications of diabetes, such as, cardiovascular complications, neuropathy, nephropathy, retinopathy, and cataract genesis. It reduces glucose to sorbitol in the presence of NADPH and the major cause of diabetes complications could be the change in the osmotic pressure due to the accumulation of sorbitol. An activated form of hAR (activated hAR or ahAR) poses a potential obstacle in the development of diabetes drugs as hAR-inhibitors are ineffective against ahAR. The therapeutic efficacy of such drugs is compromised when a large fraction of the enzyme (hAR) undergoes conversion to the activated ahAR form as has been observed in the diabetic tissues. In the present study, attempts have been made to employ systems biology strategies to identify the elementary nodes of human polyol metabolic pathway, responsible for normal metabolic states, followed by the identification of natural potent inhibitors of the activated form of hAR represented by the mutant C298S for possible antidiabetic applications. Quantum Mechanical Molecular Mechanical docking strategy was used to determine the probable inhibitors of ahAR. Rosmarinic acid was found as the most potent natural ahAR inhibitor and warrants for experimental validation in the near future.

Phytophthora infestans specific phosphorylation patterns and new putative control targets

In this study we applied biomathematical searches of gene regulatory mechanisms to learn more about oomycete biology and to identify new putative targets for pesticides or biological control against Phytophthora infestans. First, oomycete phylum-specific phosphorylation motifs were found by discriminative n-gram analysis. We found 11.600 P. infestans specific n-grams, mapping 642 phosphoproteins. The most abundant group among these related to phosphatidylinositol metabolism. Due to the large number of possible targets found and our hypothesis that multi-level control is a sign of usefulness as targets for intervention, we identified overlapping targets with a second screen. This was performed to identify proteins dually regulated by small RNA and phosphorylation. We found 164 proteins to be regulated by both sRNA and phosphorylation and the dominating functions where phosphatidylinositol signalling/metabolism, endocytosis, and autophagy. Furthermore we performed a similar regulatory study and discriminative n-gram analysis of proteins with no clear orthologs in other species and proteins that are known to be unique to P. infestans such as the RxLR effectors, Crinkler (CRN) proteins and elicitins. We identified CRN proteins with specific phospho-motifs present in all life stages. PITG_12626, PITG_14042 and PITG_23175 are CRN proteins that have species-specific phosphorylation motifs and are subject to dual regulation.

Cytoplasmic sphingosine-1-phosphate pathway modulates neuronal autophagy

Autophagy is an important homeostatic mechanism that eliminates long-lived proteins, protein aggregates and damaged organelles. Its dysregulation is involved in many neurodegenerative disorders. Autophagy is therefore a promising target for blunting neurodegeneration. We searched for novel autophagic pathways in primary neurons and identified the cytosolic sphingosine-1-phosphate (S1P) pathway as a regulator of neuronal autophagy. S1P, a bioactive lipid generated by sphingosine kinase 1 (SK1) in the cytoplasm, is implicated in cell survival. We found that SK1 enhances flux through autophagy and that S1P-metabolizing enzymes decrease this flux. When autophagy is stimulated, SK1 relocalizes to endosomes/autophagosomes in neurons. Expression of a dominant-negative form of SK1 inhibits autophagosome synthesis. In a neuron model of Huntington’s disease, pharmacologically inhibiting S1P-lyase protected neurons from mutant huntingtin-induced neurotoxicity. These results identify the S1P pathway as a novel regulator of neuronal autophagy and provide a new target for developing therapies for neurodegenerative disorders.