Computational Modeling of the Staphylococcal Enterotoxins and Their Interaction with Natural Antitoxin Compounds

An ethnopharmacological approach to evaluate antiparasitic and health-promoting abilities of Pueraria tuberosa (Willd.) DC. in livestock

In eastern India, the tubers of Pueraria tuberosa (Willd.) DC. are used by the ethnic communities for its wide range of medicinal and nutritional value, especially to rejuvenate livestock health and to treat helminthiasis. The study is aimed to evaluate the ethnoveterinary medicinal importance of P. tuberosa as anthelmintic, to verify its nontoxic nature and identify the most potent phytoconstituents aided by in silico molecular docking technique. Ethnomedicinal data collected from 185 informants were quantitatively analyzed employing eight quantitative indices to highlight the use diversity and most frequently used part of the plant. High scores of certain indices employed, such as Use Value (UV = 0.52), Fidelity Level (FL = 68.42%) and Tissue Importance Value (TIV = 1) clearly illustrate an ethnomedicinal lead regarding medico-nutritional benefits of the tuber part used against intestinal helminthic diseases of veterinary animals. Based on this ethno-guided lead, root tuber has been investigated for its chemical profiling by the estimation of total phenolics, flavonoids, tannins and alkaloids, along with HPLC and GC-MS analyses. Anthelmintic property was evaluated with the tuber extracts by in vitro studies on some helminths of livestock and poultry birds, and it showed promising results against the tested parasites namely Cotylophoron cotylophorum, Raillietina tetragona and Setaria cervi. Toxicity assessments of tuber extract through in vitro and in vivo methods were performed using Vero cells and BALB/c mice. Nontoxic nature of the studied tuber extract was observed even in higher experimental doses. Out of 12 phytocompounds identified by GC-MS analysis, one compound [Morphinan-4,5-epoxy-3,6-di-ol,6- (7-nitrobenzofurazan-4-yl) amino-] exhibited the best binding conformations in cost of the lowest binding energy values with six target proteins that include one anti-inflammatory, one antioxidant, and four anthelmintic proteins. The findings of our study are found very encouraging to evaluate this tuber drug furthermore intensively towards the development of anthelmintic veterinary medicine.

Chromatographic Fingerprinting of Cacao Pod Husk Extracts (Theobroma cacao L.): Exploring Antibacterial, Antioxidant, and Antidiabetic Properties with In Silico Molecular Docking Analysis

Natural drugs derived from plants are becoming more popular because of their apparent biological efficacy, affordability, and safety. A byproduct of cocoa farms, cocoa pod husk (CPH), is often disregarded yet contains an abundance of phenolic chemicals that have antimicrobial and antioxidant features, which has led to intensive investigation into possible biomedical applications. In order to identify crucial functional groups and phytochemical components, we carefully examined the 80% ethanol and dichloromethane extracts of CPH using gas chromatography-mass spectrometry (GC-MS) and HPLC. The antibacterial and antioxidant properties of such extracts and their impact on cytotoxicity and α-glucosidase were explored. According to our results, the 80% ethanol and dichloromethane extracts contained 19 and 12 phytochemical components, respectively. Interestingly, at 250 µg/mL, all CPH extracts showed strong antibacterial properties that totally prevented the bacterial growth. At 66.6% and 82.7%, respectively, the ethanol and dichloromethane extracts showed impressive antioxidant and DPPH scavenging capabilities where the ethanol extract showed a substantially lower IC50 value of 35.26 µg/mL than the dichloromethane extract, which had an IC50 value of 23.88 µg/mL. Furthermore, the α-glucosidase inhibitory effect of the dichloromethane extract was found to be better, as shown by its IC50 value of 126.5 µg/mL, which was lower than that of the ethanol extract at 151.3 µg/mL. The extracts' compatibility was verified by cytotoxicity tests, which revealed no appreciable alterations in the cell lines. Additionally, novel in silico molecular docking experiments were performed on 25 discovered compounds, providing insight into their possible bioactivity. Broad-spectrum activities of extracts were confirmed by molecular docking investigations aimed at interacting with α-glucosidase proteins. Our thorough analysis makes CPH extracts seem like the excellent candidates for biomedical uses. These results provide new insights into the therapeutic potential of CPH extracts and pave the way for the development of innovative medications and natural remedies.

Blood proteins self-assembly, staphylococcal enterotoxins-interaction, antibacterial synergistic activities of biogenic carbon/FeSO4/Cu/CuO nanocomposites modified with three antibiotics

INTRODUCTION

Nanocomposites based on copper, iron, and carbon materials are novel nanomaterials with both antibacterial and biocompatibility properties considerable to fight against multidrug-resistant bacteria.

METHODS

In this study, phytogenic carbon/FeSO4/Cu/CuO nanocomposites modified by three antibiotics including tetracycline, amoxicillin, and penicillin were employed to hinder antibiotic resistant bacteria of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Interaction of albumin and hemoglobin as major blood proteins with these nanocomposites were evaluated by SEM, FTIR, and AFM techniques. As in silico study, molecular docking properties of staphylococcal enterotoxin toxin A and B with (Z)-α-Bisabolene epoxide, (E)-Nerolidol, α-Cyperone, daphnauranol C, nootkatin, and nootkatone as major secondary metabolites of Daphne mucronata were obtained by AutoDock Vina program.

RESULTS

Physicochemical characterization of nanocomposites showed (Zeta potential (- 5.09 mV), Z-average (460.2 d.nm), polydispersity index (0.293), and size range of 44.58 ± 6.78 nm). Results of both in vitro and in silico surveys disclosed significant antibacterial activity of antibiotic functionalized carbon/FeSO4/Cu/CuO nanocomposites compared to antibiotics alone towards Gram-negative and Gram-positive bacteria.

CONCLUSION

Synergistic activity of bio-fabricated carbon/FeSO4/Cu/CuO nanocomposites with antibiotics may be affected by main parameters of concentration and ratio of antibacterial agents, physicochemical properties of nanocomposites, bacterial type (Gram-negative or Gram-positive), antibacterial mechanisms, and chemical structure of antibiotics.

Stability and Resistance to Proteolysis of Enterotoxins SEC and SEL Produced by Staphylococcus epidermidis and Staphylococcus aureus

The only staphylococcal enterotoxins produced by Staphylococcus epidermidis include SEC_epi and SEL_epi, whereas Staphylococcus aureus produces orthologous SECs and SEL having different sequences. We compared S. epidermidis and S. aureus SECs and SELs in terms of resistance to proteolysis and both, thermal and chemical stability. We show that SEC_epi and SEL_epi produced by S. epidermidis have similar resistance to proteolysis if compared with their respective orthologues produced by S. aureus. Studied S. epidermidis and S. aureus SEC variants incubated with pepsin at pH 2.0 were found to be more resistant to proteolysis than SELs. SELs turned out to be more resistant than SECs to proteolysis with trypsin at pH 8.0. SEC_epi was found to be more resistant to thermal denaturation if compared with its S. aureus orthologues. The S. epidermidis and S. aureus SEC variants were found to have higher thermal stability than SELs. Our data indicate that, due to their high stability, the enterotoxins SEC_epi and SEL_epi produced in food by S. epidermidis may pose a food safety risk comparable with that posed by S. aureus enterotoxins.

A Sensitive Immunodetection Assay Using Antibodies Specific to Staphylococcal Enterotoxin B Produced by Baculovirus Expression

Staphylococcal enterotoxin B (SEB) is a potent bacterial toxin that causes inflammatory stimulation and toxic shock, thus it is necessary to detect SEB in food and environmental samples. Here, we developed a sensitive immunodetection system using monoclonal antibodies (mAbs). Our study is the first to employ a baculovirus expression vector system (BEVS) to produce recombinant wild-type SEB. BEVS facilitated high-quantity and pure SEB production from suspension-cultured insect cells, and the SEB produced was characterized by mass spectrometry analysis. The SEB was stable at 4 °C for at least 2 years, maintaining its purity, and was further utilized for mouse immunization to generate mAbs. An optimal pair of mAbs non-competitive to SEB was selected for sandwich enzyme-linked immunosorbent assay-based immunodetection. The limit of detection of the immunodetection method was 0.38 ng/mL. Moreover, it displayed higher sensitivity in detecting SEB than commercially available immunodetection kits and retained detectability in various matrices and S. aureus culture supernatants. Thus, the results indicate that BEVS is useful for producing pure recombinant SEB with its natural immunogenic property in high yield, and that the developed immunodetection assay is reliable and sensitive for routine identification of SEB in various samples, including foods.

Proteomic analysis of adipose tissue revealing differentially abundant proteins in highly efficient mid-lactating dairy cows

The improvement of nutrient utilization efficiency in dairy cows represents an important task in view of the current rising demand for animal products and sustainable resource usage. In this perspective, the identification of appropriate markers to identify the most efficient animals for dairy production becomes a crucial factor. Residual feed intake (RFI), which represents the difference between predicted and actual intake, is used to define the efficiency of cows. In this study, subcutaneous adipose tissue (AT) was collected from five high efficient (HEF) and five low efficient (LEF) mid-lactation Holstein dairy cows, that represented subgroups of the 20% lowest RFI values (HEF) and highest 20% RFI values (LEF), out of a cohort of 155 cows that were examined for feed efficiency at the individual dairy barn at Volcani Institute, Israel. Adipose samples were examined for proteomic analysis by nano-LC/MS–MS and gene expression by RT-PCR. A total of 101 differential proteins (P ≤ 0.05 and fold change ± 1.5) and two protein networks related to feed efficiency were found between HEF and LEF cows. Among the enriched top canonical pathways, FAT10 signaling, EIF2 signaling, Sirtuin signaling, Acute phase response signaling, Protein ubiquitination and mTOR signaling pathways were related to feed efficiency in AT. Furthermore, abundance of transferrin (TF; FC = 78.35, P = 0.02) enriched pathways, including mTOR signaling, LXR/RXR and FXR/RXR activation was found in AT of HEF cows. Relative mRNA expression of RBM39, which is involved in energy metabolism, was decreased in AT of HEF versus LEF. The relationship found between the AT proteins and/or metabolic pathways and the feed efficiency demonstrates that AT may reflect metabolic adaptations to high efficiency, and suggests that these proteins together with their metabolic mechanisms are suitable candidates as biomarkers to identify efficient cows for dairy production.

Effects of Environmental Heat Load on Endocannabinoid System Components in Adipose Tissue of High Yielding Dairy Cows

Environmental heat load (HL) adversely affects the performance of dairy cows. The endocannabinoid system (ECS) regulates metabolism and the stress response, thus we hypothesized that HL may affect the ECS of dairy cows. Our objective was to determine the levels of endocannabinoids (eCBs) and gene and protein expressions of the ECS components in adipose tissue (AT) and plasma of early postpartum (PP) and late-lactation cows. In addition, we examined eCBs in milk, and studied the interaction of eCBs with bovine cannabinoids receptors CB1 and CB2. In the first experiment, plasma and AT were sampled from cows calving during summer (S, n = 9) or winter (W, n = 9). Dry matter intake (DMI) and energy balance (EB) were lower in S vs. W, and relative gene expressions of transient-receptor-potential-cation-channel-subfamily-V-member-1 (TRPV1), the cannabinoid receptors CNR1 (CB1) and CNR2 (CB2), and monoglyceride lipase (MGLL) were decreased in AT of S compared to W. Protein abundance of peroxisome proliferator-activated-receptor-alpha (PPAR-α) was decreased, while tumor-necrosis factor-α (TNF-α) was increased in AT of S vs. W. Other components of the ECS were not different between S and W calving cows. To study whether the degree of HL may affect the ECS, we performed a second experiment with 24 late-lactation cows that were either cooled (CL) or not cooled (heat-stressed; HS) during summer. DMI was lower in HS vs. CL, AT protein abundance of PPAR-α was lower, and TRPV1 tended to be lower in HS vs. CL, but other components of the ECS were not different between groups. Milk levels of 2-arachidonoylglycerol (2-AG) tended to increase in HS vs. CL. Additionally, modeling of the bovine cannabinoid receptors demonstrated their binding to anandamide and 2-AG. Environmental HL, possibly via lower intake, is associated with limited alterations in ECS components in AT of dairy cows.

Hazard of Staphylococcal Enterotoxins in Food and Promising Strategies for Natural Products against Virulence

Staphylococcal enterotoxins (SEs) secreted by Staphylococcus aureus frequently contaminate food and cause serious foodborne diseases but are ignored during food processing and even cold-chain storage. Notably, SEs are stable and resistant to harsh sterilization environments, which can induce more serious hazards to public health than the bacterium itself. Therefore, it is necessary to develop promising strategies to control SE contamination in food and improve food safety. Natural products not only have various pharmaceutical properties, such as antimicrobial and antitoxin activities, but they are also eco-friendly, safe, nutritive, and barely drug-resistant. Here, the hazards of SEs and the promising natural compounds with different inhibitory mechanisms are summarized and classified. The key points of future research and applications for natural products against bacterial toxin contamination in food are also prospected. Overall, this review may provide enlightening insights for screening effective natural compounds to prevent foodborne diseases caused by bacterial toxins.

Antioxidant Resveratrol Increases Lipolytic and Reduces Lipogenic Gene Expression under In Vitro Heat Stress Conditions in Dedifferentiated Adipocyte-Derived Progeny Cells from Dairy Cows

Heat stress (HS) induces oxidative stress by increasing reactive oxygen species (ROS), and the polyphenol resveratrol (RSV) has been shown to have antioxidant properties by reducing ROS. Hence, we aimed to examine the effects of RSV, HS and their interaction on bovine adipocytes. We generated bovine dedifferentiated adipocyte-derived progeny (DFAT) cells from subcutaneous adipose tissue and examined the effects of RSV (100 µM), heat conditions: isothermal (ISO-37 °C), short heat (SH-41.2 °C for 1 h) and long HS (LH-41.2 °C for 16 h), and their interaction on gene expression in DFAT-cells. In medium of DFAT-cells treated with RSV, malondialdehyde levels were reduced and oxygen-radical absorbance-capacity levels were increased compared to control. Treating DFAT-cells with RSV increased the relative mRNA expression of stress-induced-phosphoprotein-1 (STIP1) and the expression of hormone-sensitive-lipase (LIPE) and perilipin-1 (PLIN1), whereas it reduced the expressions of fatty-acid-synthase (FASN) and of pro-inflammatory chemotactic-C-C-motif-chemokine-ligand-2 (CCL2) also under HS. Moreover, reduced protein abundance of FASN was found in RSV-treated DFAT-cells compared to controls. Molecular docking of RSV with FASN confirmed its possible binding to FASN active site. This work demonstrates that RSV has an antioxidant effect on bovine DFAT cells and may induce adipose lipolysis and reduce lipogenesis also under in vitro HS conditions.

Molecular Binding and Simulation Studies of Staphylococcus aureus Superantigens with Flavonoid Compounds

BACKGROUND

Superantigens of Staphylococcus aureus namely enterotoxin A, exfoliative toxin A, and Toxic shock syndrome toxin-1 cause detrimental effects on the cells of the immune system.

METHODS

In this work, the toxins were downloaded from the Protein DataBank database and energies were minimized using KoBaMIN server. Forty flavonoids compounds were identified by pubchem compound database through extensive literature study and their 3D structures were obtained by submitting SMILES to CORINA tool. Based on Lipinski's rule of five, the molecules were filtered that resulted in 27 compounds. Molecular docking was performed for identifying the binding and interaction sites of flavonoids with the toxins using Autodock 4.

RESULTS AND CONCLUSION

The docked complexes were then subjected to molecular dynamics simulation using Gromacs. The analysis revealed the stability of the complexes as indicated by three hydrogen bonds formed during the simulation time period of 20 ns.

Identification of Salicylic Acid Mechanism against Leaf Blight Disease in Oryza sativa by SR-FTIR Microspectroscopic and Docking Studies

The present study was to investigate the application and mechanism of salicylic acid (SA) as SA-Ricemate for the control of leaf blight disease using a Synchrotron Radiation-based Fourier-Transform Infra-Red (SR-FTIR) microspectroscopy and docking studies. After treating rice plants cv. KDML 105 with SA-Ricemate, the leaves were inoculated with Xanthomonas oryzae pv. oryzae, the causal agent of leaf blight, and disease severity were assessed. The leaves were also used to detect changes in endogenous SA content. The results indicated that SA-Ricemate, as an activated compound, reduced disease severity by 60% at three weeks post-inoculation and increased endogenous content by 50%. The SR-FTIR analysis of changes in the mesophyll of leaves (treated and untreated) showed that the groups of lipids, pectins, and proteins amide I and amide II occurred at higher values, and polysaccharides were shown at lower values in treated compared to untreated. Besides, docking studies were used to model a three-dimensional structure for Pathogenesis-related (PR1b) protein and further identify its interaction with SA. The results showed that ASP28, ARG31, LEU32, GLN97, and ALA93 are important residues that have strong hydrogen bonds with SA. The docking results showed that SA has a good interaction, confirming its role in expression.

Structure prediction, molecular simulations of RmlD from Mycobacterium tuberculosis, and interaction studies of Rhodanine derivatives for anti-tuberculosis activity

Tuberculosis is the most dangerous disease causing maximum deaths than any other, caused by single infectious agent. Due to multidrug resistant of Mycobacterium tuberculosis strains, there is a need of new drugs and drug targets. In this work, we have selected RmlD (α-dTDP-6-deoxy-lyxo-4-hexulose reductase) in the dTDP Rhamnose pathway as drug target to control tuberculosis using Rhodanine analogues. In order to study interaction of RmlD with Rhodanine analogues, a three-dimensional model based on crystal structures such as 1VLO from Clostridium, 1KBZ from Salmonella typhimurium, and 2GGS from Sulfolobus was generated using Modeller 9v7. The modeled structure reliability has been checked using programs such as Procheck, What if, Prosa, Verify 3D, and Errat. In an attempt to find new inhibitors for RmlD enzyme, docking studies were done with a series of Rhodanine and its analogues. Detailed analysis of enzyme-inhibitor interactions identified specific key residues, SER5, VAL9, ILE51, HIS54, and GLY55 which were important in forming hydrogen bonds in binding affinity. Homology modeling and docking studies on RmlD model provided valuable insight information for designing better inhibitors as novel anti-tuberculosis drugs by rational method.

Nerolidol improves cardiac function in spontaneously hypertensive rats by inhibiting cardiac inflammation and remodelling associated TLR4/ NF-κB signalling cascade

Toll-like receptor 4 (TLR4) is an important mediator of hypertension and AngII induced cardiac inflammation and remodelling. In this study, the potential of nerolidol to ameliorate hypertension induced cardiac injuries and the underlying mechanism of action was explored by using in vitro and in vivo models. The in vitro analysis was performed on AngII challenged H9c2 cells and their ability to overcome cardiac inflammation and cardiac remodelling effects was determined by evaluating TLR4/NF-κB signalling cascade using Western blot analysis and immunofluorescence. The results were further ascertained using in vivo experiments. Eighteen week old male rats were randomly allocated into different groups i.e. Wistar Kyoto (WKY) rats, hypertensive SHRs, SHRs treated with a low-dose (75 mg/kg b.w) and high-dose of nerolidol (150 mg/kg b.w) and SHRs treated with captopril (50 mg/kg b.w) through oral gauge and finally analysed through echocardiography, histopathological techniques and molecular analysis. The results show that nerilodol target TLR4/NF-κB signalling and thereby attenuate hypertension associated inflammation and oxidative stress thereby provides effective cardioprotection. Echocardiography analysis showed that nerolidol improved cardiac functional characteristics including Ejection Fraction and Fractional Shortening in the SHRs. Collectively, the data of the study demonstrates nerolidol as a cardio-protective agent against hypertension induced cardiac remodelling.

Plant systemic acquired resistance compound salicylic acid as a potent inhibitor against SCF (SKP1-CUL1-F-box protein) mediated complex in Fusarium oxysporum by homology modeling and molecular dynamics simulations

Fusarium oxysporum causes significant economic losses in many crop plants by causing root rot, necrosis, and wilting symptoms. Homology and molecular dynamics studies are promising tools for the detection in F. oxysporum of the systemic resistance compound, salicylic acid, for control of the SKP1-CUL1-F-box protein complex. The structure of SKP1-CUL1-F-box subunit Skp1 from F. oxysporum is produced by Modeler 9v7 for the conduct of docking studies. The Skp1 structure is based on the yeast Cdc4/Skp1 (PDB ID: 3MKS A) crystal structure collected by the Protein data bank. Applying molecular dynamic model simulation methods to the final predicted structure and further evaluated by 3D and PROCHECK test programmers, the final model is verified to be accurate. Applying GOLD 3.0.1, SCF Complex Skp1 is used to prevent stress-tolerant operation. The SKP1-CUL1-F-box model is predicted to be stabilized and tested as a stable docking structure. The predicted model of the SCF structure has been stabilized and confirmed to be a reliable structure for docking studies. The results indicated that GLN8, LYS9, VAL10, TRP11, GLU48, ASN49 in SCF complex are important determinant residues in binding as they have strong hydrogen bonding with salicylic acid, which showed best docking results with SKP1-CUL1-F-box complex subunit Skp1 with docking score 25.25KJ/mol. Insilco studies have been used to determine the mode of action of salicylic acid for Fusarium control. Salicylic acid hinders the SKP1-CUL1-F-box complex, which is important in protein-like interactions through hydrogen bodings. Results from docking studies have shown that the best energy for SKP1-CUL1-F-box was salicylic acid.Communicated by Ramaswamy H. Sarma.

GC-MS analysis of phytoconstituents from Amomum nilgiricum and molecular docking interactions of bioactive serverogenin acetate with target proteins

Amomum nilgiricum is one of the plant species reported from Western Ghats of India, belonging to the family Zingiberaceae, with ethno-botanical values, and is well-known for their ethno medicinal applications. In the present investigation, ethyl acetate and methanol extracts of A. nilgiricum were analyzed by Fourier transform infrared spectrometer (FTIR) and gas chromatography-mass spectrometry (GC-MS) to identify the important functional groups and phytochemical constituents. The FTIR spectra revealed the occurrence of functional characteristic peaks of aromatic amines, carboxylic acids, ketones, phenols and alkyl halides group from leaf and rhizome extracts. The GC-MS analysis of ethyl acetate and methanol extracts from leaves, and methanol extract from rhizomes of A. nilgiricum detected the presence of 25 phytochemical compounds. Further, the leaf and rhizome extracts of A. nilgiricum showed remarkable antibacterial and antifungal activities at 100 mg/mL. The results of DPPH and ferric reducing antioxidant power assay recorded maximum antioxidant activity in A. nilgiricum methanolic leaf extract. While, ethyl acetate leaf extract exhibited maximum α-amylase inhibition activity, followed by methanolic leaf extract exhibiting aldose reductase inhibition. Subsequently, these 25 identified compounds were analyzed for their bioactivity through in silico molecular docking studies. Results revealed that among the phytochemical compounds identified, serverogenin acetate might have maximum antibacterial, antifungal, antiviral, antioxidant and antidiabetic properties followed by 2,4-dimethyl-1,3-dioxane and (1,3-13C2)propanedioic acid. To our best knowledge, this is the first description on the phytochemical constituents of the leaves and rhizomes of A. nilgiricum, which show pharmacological significance, as there has been no literature available yet on GC-MS and phytochemical studies of this plant species. The in silico molecular docking of serverogenin acetate was also performed to confirm its broad spectrum activities based on the binding interactions with the antibacterial, antifungal, antiviral, antioxidant and antidiabetic target proteins. The results of the present study will create a way for the invention of herbal medicines for several ailments by using A. nilgiricum plants, which may lead to the development of novel drugs.

In vitro and in silico analysis of L. donovani enoyl acyl carrier protein reductase - A possible drug target

The emergence of increased resistance to the available drugs has created a situation that demands to find out more specific molecular drug targets for Leishmaniasis. The enoyl acyl carrier protein reductase (ENR), a regulatory enzyme in type II fatty acid synthesis, was confirmed as a novel drug target and triclosan as its specific inhibitor in many microorganisms. In this study, the triclosan was tested for the leishmanicidal property against Leishmania donovani (L. donovani) and the results of in vitro and ex vivo drug assays on promastigotes and amastigotes showed that triclosan possessed antileishmanial activity with a half minimal inhibitory concentration (IC₅₀) of 30 µM. Consequently, adopting in silico approach, we have tested the triclosan's ability to bind with the L. donovani enoyl acyl carrier protein reductase (LdENR). The 3D structure of LdENR was modelled, triclosan and cofactors were docked in LdENR model and molecular dynamic simulations were performed to observe the protein-ligands interactions, stability, compactness and binding energy calculation of the ligands-LdENR complexes. The observation showed that triclosan stably interacted with LdENR in presence of both the cofactors (NADPH and NADH), however, simulation results favor NADH as a preferred co-factor for LdENR. These results support that the reduction of L. donovani growth in the in vitro and ex vivo drug assays may be due to the interaction of triclosan with LdENR, which should be confirmed through enzymatic assays. The results of this study suggest that LdENR could be a potential drug target and triclosan as a lead for Leishmaniasis.Communicated by Ramaswamy H. Sarma.

In Silico Studies on Anti-Stress Compounds of Ethanolic Root Extract of Hemidesmus indicus L

BACKGROUND

Alternative medicine is available for those diseases which cannot be treated by conventional medicine. Ayurveda and herbal medicines are important alternative methods in which the treatment is done with extracts of different medicinal plants. This work is concerned with the evaluation of anti-stress bioactive compounds from the ethanolic root extract of Hemidesmus indicus.

METHODS

Gas chromatography and Mass Spectrum studies are used to identify the compounds present in the ethanolic extract based on the retention time, area. In order to perform docking studies, Vasopressin model is generated using modeling by Modeller 9v7. Vasopressin structure is developed based on the crystal structure of neurophysin-oxytocin from Bos taurus (PDB ID: 1NPO_A) collected from the PDB data bank. Using molecular dynamics simulation methods, the final predicted structure is obtained and further analyzed by verifying 3D and PROCHECK programs, confirmed that the final model is reliable. The identified compounds are docked to vasopressin for the prediction of anti-stress activity using GOLD 3.0.1 software.

RESULTS

The predicted model of Vasopressin structure is stabilized and confirmed that it is a reliable structure for docking studies. The results indicated ARG4, THR7, ASP9, ASP26, ALA32, ALA 80 in Vasopressin are important determinant residues in binding as they have strong hydrogen bonding with phytocompounds. Among the 21 phytocompounds identified and docked, molecule Deoxiinositol, pentakis- O-(trimethylsilyl) showed the best docking results with Vasopressin.

CONCLUSION

The identified compounds were used for anti-stress activity by insilico method with Vasopressin which plays an important role in causing stress and hence selected for inhibitory studies with phytocompounds. The phytocompounds are inhibiting vasopressin through hydrogen bodings and are important in protein-ligand interactions. Docking results showed that out of twenty-one compounds, Deoxiinositol, pentakis-O-(trimethylsilyl) showed best docking energy to the Vasopressin.

Designing, docking and molecular dynamics simulation studies of novel cloperastine analogues as anti-allergic agents: homology modeling and active site prediction for the human histamine H1 receptor

The present study predicts a three-dimensional model for the histamine H1 receptor and the design of antihistamine inhibitors using cloperastine as the core molecule by docking studies. In this work, we predicted a three-dimensional structure of the histamine H1 receptor using the MODELLER9V7 software. The protein structure was developed based on the crystal structure of the histamine H1 receptor, the lysozyme chimera of Escherichia virus T4 (PDB ID: 3RZE_A) target collected from the PDB data bank. Using molecular dynamics simulation methods, the final predicted structure is obtained and further analyzed by VERIFY3D and PROCHECK programs, confirming that the final model is reliable. The drug derivatives of cloperastine were designed and docking was performed with the designed ligands along with the drug. The predicted model of the histamine H1 receptor structure is stable and confirms that it is a reliable structure for docking studies. The results indicate that MET 183, THR 184 and ILE 187 in the histamine H1 receptor are important determinant residues for binding as they have strong hydrogen bonding with cloperastine derivatives. The drug derivatives were docked to the histamine H1 receptor protein by hydrogen bonding interactions and these interactions played an important role in the binding studies. The molecule 1-{2-[(4-chlorophenyl) (phenyl) methoxy] ethyl}-4-methylenepiperidine showed the best docking results with the histamine H1 receptor. The docking results predicted the best compounds, which may act as better drugs than cloperastine and in the future, these may be developed for anti-allergy therapy.

The present study predicts a three-dimensional model for the histamine H1 receptor and the design of antihistamine inhibitors using cloperastine as the core molecule by docking studies.