Evaluation of antimycobacterial and synergistic activity of plants selected based on cheminformatic parameters

Background: Drug resistance is a major public health problem and a threat to progress made in bovine tuberculosis care and control worldwide. This study aimed at evaluating anti-mycobacterial and synergistic activity of some medicinal plants that were selected by cheminformatics studies against Mycobacterium bovis

Methods: Considering the strong synergistic antimycobacterial action of oleanolic acid in combination with tuberculosis drugs, NCBI database was explored to find the compounds with over 80% similarity to oleanolic acid, called S1. Plants containing S1-type compounds were traced to and resulted in five plants, including Datura stramonium, Boswellia serrata Lavandula stoechas, Rosmarinus officinalis, and Thymus vulgaris, as experimental samples. Crude extracts were prepared by percolation using 80% ethanol or as the product of a pharmaceutical company. The extracts were screened against Mycobacterium bovisusing broth microdilution method and Alamar Blue Assay. Extracts from these plants were used in combination with isoniazid and ethambutol to investigate the possibility of synergy with respect to antimycobacterial activity

Results: The extracts from D. stramonium, B. serrata a, L. stoechas, R. officinalis, and T. Thymus vulgaris showed antimycobacterial activity of 375, 125, 250, 187.5, 500 microg/ml, respectively. The best synergistic results were for L. stoechas and D. stramonium in combination with ethambutol, the fractional inhibitory concentration index was 0.125 microg/ml for both

Conclusion: The observed antimycobacterial and synergistic activities are completely novel and obtained from targeted screening designed according to cheminformatics strategy. As for the synergistic action of the extracts, they could be used as supplements in bTB treatment

In silico screening and evaluation of the anticonvulsant activity of docosahexaenoic acid-like molecules in experimental models of seizures

Background: Resistance to antiepileptic drugs and the intolerability in 20-30% of the patients raises demand for developing new drugs with improved efficacy and safety. Acceptable anticonvulsant activity, good tolerability, and inexpensiveness of docosahexaenoic acid [DHA] make it as a good candidate for designing and development of the new anticonvulsant medications

Methods: Ten DHA-based molecules were screened based on in silico screening of DHA-like molecules by root-mean-square deviation of atomic positions, the biological activity score of Professional Association for SQL Server, and structural requirements suggested by pharmacophore design. Anticonvulsant activity was tested against clonic seizures induced by pentylenetetrazole [PTZ, 60 mg/kg, i.p.] and tonic seizures induced by maximal electroshock [MES, 50 mA, 50 Hz, 1 ms duration] by intracerebroventricular [i.c.v.] injection of the screened compounds to mice

Results: Among screened compounds, 4-Phenylbutyric acid, 4-Biphenylacetic acid, phenylacetic acid, and 2-Phenylbutyric acid showed significant protective activity in pentylenetetrazole test with ED[50] values of 4, 5, 78, and 70 mM, respectively. In MES test, shikimic acid and 4-tert-Butylcyclo-hexanecarboxylic acid showed significant activity with ED[50] values 29 and 637 mM, respectively. Effective compounds had no mortality in mice up to the maximum i.c.v. injectable dose of 1 mM

Conclusion: Common electrochemical features and three-dimensional spatial structures of the effective compounds suggest the involvement of the anticonvulsant mechanisms similar to the parent compound DHA

Isolation and identification of phyllospheric bacteria possessing antimicrobial activity from Astragalus obtusifolius, Prosopis juliflora, Xanthium strumarium and Hippocrepis unisiliqousa

Background: The widespread utilization of antimicrobial compounds has caused emergence of resistant microorganisms in the world. Hence, the research to probe the products with antimicrobial features has led to finding natural habitats and discovering new pharmaceutical products

Methods: In this study, an attempt was made to explore the niche of novel habitat to isolate pyllospheric bacteria from the above ground parts [stems and leaves] of Astragalus obtusifolius, Prosopis juliflora, Xanthium strumarium, and Hippocrepis unisiliqousa to evaluate their antimicrobial features. The inhibitory effects of these strains on the growth of two fungi [Aspergillus niger, Aspergillus fumigatus], two yeasts [Saccharomyces cerevisiae, Candida albicans] and six bacteria [Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella typhi, Streptococcus pyogenes] were tested

Results: In total, 113 bacterial strains were isolated. Twenty five bacterial strains [B-1 to B-25] indicated promising antimicrobial [antibacterial and antifungal] activities against aforementioned pathogens. The identification of the bacterial strains was ascertained by morphological, physiological, biochemical tests and two strains with the strongest antimicrobial activities were further characterized based on 16s rRNA sequencing. These two strains were identified as Bacillus amyloliquefaciens

Conclusion: Our results provide evidence that phyllospheric microorganisms are capable of producing some compounds with antimicrobial properties

Identification and evaluation of novel drug targets against the human fungal pathogen Aspergillus fumigatus with elaboration on the possible role of RNA-binding protein

Bakground: Aspergillus fumigatus is an airborne opportunistic fungal pathogen that can cause fatal infections in immunocompromised patients. Although the current anti-fungal therapies are relatively efficient, some issues such as drug toxicity, drug interactions, and the emergence of drug-resistant fungi have promoted the intense research toward finding the novel drug targets

Methods: In search of new antifungal drug targets, we have used a bioinformatics approach to identify novel drug targets. We compared the whole proteome of this organism with yeast Saccharomyces cerevisiae to come up with 153 specific proteins. Further screening of these proteins revealed 50 potential molecular targets in A. fumigatus. Amongst them, RNA-binding protein [RBP] was selected for further examination. The aspergillus fumigatus RBP [AfuRBP], as a peptidylprolyl isomerase, was evaluated by homology modeling and bioinformatics tools. RBP-deficient mutant strains of A. fumigatus were generated and characterized. Furthermore, the susceptibility of these strains to known peptidylprolyl isomerase inhibitors was assessed

Results: AfuRBP-deficient mutants demonstrated a normal growth phenotype. MIC assay results using inhibitors of peptidylprolyl isomerase confirmed a higher sensitivity of these mutants compared to the wild type

Conclusion: Our bioinformatics approach revealed a number of fungal-specific proteins that may be considered as new targets for drug discovery purposes. Peptidylprolyl isomerase, as a possible drug target, was evaluated against two potential inhibitors and the promising results were investigated mechanistically. Future studies would confirm the impact of such target on the antifungal discovery investigations

Cheminformatics-based anticoagulant study of traditionally used medicinal plants

Background: Medicinal plants, as a complementary medicine, have been used to treat various diseases since ancient times. These plants have numerous beneficial applications and are the source of certain conventional drugs. In diseases such as stroke and ischemia, which are caused by several factors, abnormal coagulation is an important causative factor. Accordingly, novel and effective therapies such as herbal remedies should be practiced to prevent such lethal diseases

Methods: Using the available databases such as Google Scholar and PubMed, the previously reported anticoagulant compounds and plants possessing anticoagulant activity were identified and collected in two separate lists. Next, the fast and cost-effective cheminformatics methods incorporated in PubChem were applied to detect some compounds similar to reported anticoagulants. Subsequently, 15 native medical plants of Iran containing the potential anticoagulants were selected. The selected plants were purchased and chopped, and the potential compounds were extracted by ethanol. Then three concentrations of extracts [1, 10, and 100 micro g per ml] were made. Finally, anticoagulant effect of the selected plants was evaluated by in vitro prothrombin time and activated partial thromboplastin time coagulation tests

Results: Among the 15 selected medicinal plants, three plants, including Terminalia bellirica [P=0.0019], Astragalus arbusculinus [P=0.0021], and Origanum vulgare [P=0.0014] showed a more promising anticoagulant effect in comparison to the control

Conclusion: The anticoagulant activity was identified for the first time in these three plants. Further in vivo study and mechanism of action assay are required to be performed on these three plants, which could be suitable candidates for use as natural anticoagulant medicines

Anticonvulsant effect of cicer arietinum seed in animal models of epilepsy: introduction of an active molecule with novel chemical structure

Cicer arietinum [Chickpea] is one of the most important harvests in the world with high nutritional value. Lack of essential oils in the seeds of Chickpea is an advantage in search for drug-like molecules with less toxicity. We evaluated anticonvulsant effect of C. arietinum in common animal models of epilepsy. Dichloromethane extract was obtained from C. arietinum seeds by percolation. Acute toxicity of the extract was assessed in mice. Protective effect of the extract was examined against tonic seizures induced by maximal electroshock [MES; 50 mA, 50 Hz, 1 s] in mice, clonic seizures induced by pentylenetetrazole [PTZ; 60 mg/kg, i.p.] in mice, and electrical kindling model of complex partial seizures in rats. The extract was fractionated by nhexane to f1 and f2 fractions. The extract and fractions underwent phytochemical analysis by thin layer chromatography. The active anticonvulsant fraction, f1, was subjected to matrix assisted laser desorption/ionization [MALDI] mass analysis. The crude extract had neither toxicity up to 7 g/kg nor protective activity in MES and kindling models. However, it significantly inhibited clonic seizures induced by PTZ. f1 fraction mimicked protective effect of the extract. Phytochemical screening revealed the presence of considerable amount of alkaloids in the extract and fractions. Moreover, a novel structural class was detected in f1 fraction. Finding an anticonvulsant molecule pertaining to a new structural class in the seeds of C. arietinum promises an effective and inexpensive source of antiepileptic medication. Further studies are needed to identify its mechanism of action and more clues into its structure-activity relationship.

In-silico metabolome target analysis towards PanC-based antimycobacterial agent discovery

Mycobacterium tuberculosis, the main cause of tuberculosis [TB], has still remained a global health crisis especially in developing countries. Tuberculosis treatment is a laborious and lengthy process with high risk of noncompliance, cytotoxicity adverse events and drug resistance in patient. Recently, there has been an alarming rise of drug resistant in TB. In this regard, it is an unmet need to develop novel antitubercular medicines that target new or more effective biochemical pathways to prevent drug resistant Mycobacterium. Integrated study of metabolic pathways through in-silico approach played a key role in antimycobacterial design process in this study. Our results suggest that pantothenate synthetase [PanC], anthranilate phosphoribosyl transferase [TrpD] and 3-isopropylmalate dehydratase [LeuD] might be appropriate drug targets. In the next step, in-silico ligand analysis was used for more detailed study of chemical tractability of targets. This was helpful to identify pantothenate synthetase [PanC, Rv3602c] as the best target for antimycobacterial design procedure. Virtual library screening on the best ligand of PanC was then performed for inhibitory ligand design. At the end, five chemical intermediates showed significant inhibition of Mycobacterium bovis with good selectivity indices [SI] >/= 10 according to Tuberculosis Antimicrobial Acquisition and Coordinating Facility of US criteria for antimycobacterial screening programs

Synthesis and antimycobacterial activity of some triazole derivatives - new route to functionalized triazolopyridazines

A series of cyclic analogues of bioactive thiosemicarbazide derivatives have been synthesized as potential antimycobacterial agents. The 4-amino-1,2,4-triazole-5-thione analogues [Ia-f] were prepared by heating a mixture of thiocarbohydrzide and appropriate carboxylic acids. Reaction of thiocarbohydrazide with gamma-ketoesters in the presence of sodium methoxide furnished triazolopyridazine derivatives IIa-b. Finally, condensation of 4-amino-1,2,4-triazole-5-thione with some aldehydes gave Schiff bases IIIa-e. After characterization by different spectroscopic and analytical methods, the derivatives were tested for their inhibitory activity against Mycobacterium bovis BCG. Among the derivatives, compound Ib proved to be the most potent derivatives with MIC value of 31.25 microg/mL. Given the fact that 4-amino-1,2,4-triazole-5-thiones Ia-f were the most active derivatives, it could be suggested that this group of derivatives have the potential to be considered as lead compounds for future optimization efforts

Computational survey of FHIT, a putative human tumor suppressor, truncates structure

Fragile Histidine Triad protein [FHIT], as a known tumor suppressor protein, has been proposed to play crucial role in inhibiting p53 degradation by MDM2. Studies have confirmed FHIT interaction with p53 or MDM2, although functional interacting domains of FHIT with MDM2 and/or p53 are not completely defined. Thus, through determining the significant structural interacting domains of FHIT, information with regard to MDM2 and p53 would be provided. As there were no previous studies evaluating the interaction of optimized important parts of target molecules, docking study was employed. Truncated structures of FHIT were screened to reveal critical sections engaging in FHIT interaction. HEX program was used in order to study the interaction of target structures. Given the total energy, FHIT structures [beta5-7, alpha1] and [alpha1] of FHIT were showed to be better candidates in comparison with other structures in interaction with optimized MDM2 part. Furthermore, FHIT structures [beta4-7, alpha1] and [beta5-7, alpha1] were considered to be better than other structures in interaction with optimized p53 part. FHIT truncates which interact with MDM2 optimized part exhibited lower energy levels than FHIT truncates which interact with p53 optimized part. Our results can be useful for designing new inhibitors of this protein complex interaction which would result in tumor repression

Synthesis and antimycobacterial activity of symmetric thiocarbohydrazone derivatives against Mycobacterium bovis BCG

In this work, we reported the synthesis and evaluation of antimycobacterial and antifungal activity of a series of thiocarbohydrazone derivatives which are thiacetazone congeners. The target compounds were synthesized in superior yields by reacting thiocarbohydrazide with different aromatic aldehydes and methyl ketones. Compounds 8, 19 and 25 were found to be the most potent derivatives, exhibiting acceptable activity against Mycobacterium bovis BCG compared to thiacetazone and ethambutol as reference substances. Compounds 8, 15 and 25 exhibited the highest activity against Candida albicans. The most active compounds had a completely different aromatic ring system with various electronic, steric and lipophilic natures. This is understandable in light of the fact that carbohydrazone derivatives must undergo a metabolic activation step before exerting their anti-TB activity and different SAR rules govern each one of these two processes

Design of small molecules with HIV fusion inhibitory property based on Gp41 interaction assay

Gp41 of HIV [Human Immunodeficiency Virus] is a protein that mediates fusion between viral and cellular membranes. The agent, T-20, which has been approved for HIV inhibition, can restrain Gp41 function in the fusion process; nevertheless, it has disadvantages like instability, high cost of production and injection form to be delivered twice a day. Several molecules like NB-2 and NB-64 have been discovered that can inhibit HIV infection. These molecules were used as template compounds to design and develop more effective small molecules functioning as HIV-1 fusion inhibitors targeting Gp41. The process included in silico docking protocols using HEX and ArgusLab applications. A multisource database was created, after choosing the best molecules; they were tested in vitro for inhibitory activity by HIV-1 single-cycle model, transfected in HEK cells [293T]. Computational analysis and experimental data were combined to explore molecular properties and the most potent ones were found, with the best suitable criteria for interaction with Gp41. Several examples [DAA-6, DAA-9 and DAA-12] could inhibit infection in vitro as effective as NB-2, NB- 64. Since disadvantages of available fusion inhibitor [T-20], it seems necessary to find similar molecules to be approved and have small size providing suitable bioactivity profile. The molecules explored in this study can be good candidates for further investigations to be used as oral HIV fusion inhibitors in the future

Antifungal indole and pyrrolidine-2,4-dione derivative peptidomimetic lead design based on in silico study of bioactive peptide families

The rise of opportunistic fungal infections highlights the need for development of new antimicrobial agents. Antimicrobial Peptides [AMPs] and Antifungal Peptides [AFPs] are among the agents with minimal resistance being developed against them, therefore they can be used as structural templates for design of new antimicrobial agents. In the present study four antifungal peptidomimetic structures named C[1] to C[4] were designed based on plant defensin of Pisum sativum. Minimum inhibitory concentrations [MICs] for these structures were determined against Aspergillus niger N402, Candida albicans ATCC 10231, and Saccharomyces cerevisiae PTCC 5052. C[1] and C[2] showed more potent antifungal activity against these fungal strains compared to C[3] and C[4]. The structure C[2] demonstrated a potent antifungal activity among them and could be used as a template for future study on antifungal peptidomemetics design. Sequences alignments led to identifying antifungal decapeptide [KTCENLADTY] named KTC-Y, which its MIC was determined on fungal protoplast showing 25 [micro g/ml] against Aspergillus fumigatus Af293. The present approach to reach the antifungal molecules seems to be a powerful approach in design of bioactive agents based on AMP mimetic identification

investigation into the antifungal property of fabaceae using bioinformatics tools

Chemodiversity in plants provides sources of great value which might be helpful for finding new leads in drug discovery programs. Fabaceae as the third largest family of flowering plants was chosen to investigate its possible antifungal activity. In order to increase the effectiveness of the result, molecular similarity methods and chemical data were used. Twelve plants were selected from Fabaceae and collected from the North and South of Iran. Percolation method with 80% ethanol was used for extraction of collected plants. Antifungal activities of these extracts were determined using broth microdilution method against Candida albicans [C.albicans] ATCC 10231, Apergillus fumigatus [A. fumigatus] AF 293 and Asperigillus niger [A. niger] ATCC 16404. extracts with promising activity were screened for toxicity with larvae of Artemia salina [brine shrimp]. Dalbergia sissoo, Lathyrus pratensis, Oreophysa microphyalla, Astragalus stepporum, Ebenus stellata, Sophora alopecuroides, Ammodendron persicum and Taverneira cuneifolia showed activity against at least one of the microorganisms used in this study. According to the results of our experiment, the extracts of these plants can be used for further investigation in therapeutic research

Screening of membrane active antimicrobial metabolites produced by soil actinomycetes using membrane models

The focus of this study was antimicrobial membrane-activity of actinomycetes isolated from some soils of Iran. In this work, soil samples were collected from desert and farming zones of Northern and Central Iran. A total number of 45 actinomycetes were isolated from the soil samples. In the primary screening performed to evaluate antimicrobial activity, isolated microorganisms were analyzed in terms of their general inhibition effects to indicator strains E. coli, C. albicans, and S. cervisae. It has been found that 12 actinomycetes were effective against test microorganisms. In the secondary screening to determine membrane-active metabolites producing microorganisms, isolates having an inhibitory effect against test microorganisms, were analyzed for membrane activity using a Rapid Chromatic Detection method. Based on color changes that are easily identified by the naked eye and recorded by UV-vis spectrophotometery, two actinomycetes had membrane-activity effect and were stored for the sake of further study and identification

silico design and selection of anti-fungal Amb-polyene-analog lead molecules by virtual screening method

A major group of drugs that have been approved for the therapy of systemic fungal infections are polyene antibiotics. Amphotericin B [AmB], one of the polyene antibiotics, has been used to treat serious systemic fungal infections by binding to sterols such as ergosterol in fungal cells membrane, and is believed to form pores in the membrane and create a transmembrane ion-channel. Since all eukaryotic cells contain sterols, using AmB can cause toxicity in mammalian cells; this is the most serious unwanted side effect. Therefore, there is still a need to develop suitable antifungal compounds to be entered in the drug development pipeline. In this study, we report the screening of various compounds from the Enhanced NCI database against ergosterol and cholesterol as receptors. The strategy employed is divided into two categories, screening and docking, respectively. Screening was performed using structure search based on AmB and molecular constraints to filter compounds with physico-chemical properties similar to the polyene macrolid antibiotics. The selected compounds were docked and scored to identify structurally novel ligands that make similar interactions to AmB. Our screening approach identified several molecules with high ranking criteria mentioned above. Among these compounds, two molecules, NSC 89270 and NSC 62792 were tested for their bioactivity against three fungal strains using broth microdilution assay that presented to have moderate antifungal activity against tested fungi. Thus, they could be possible lead compounds that grant further research on them to improve their potency and compare their mechanism of action in comparison to AmB

Antibacterial effect of the Persian Gulf sea cucumber Holoturia. SP extracts on three strain of Escherichia coli

Sea cucumber is a traditional food and medical item and has been reported to exhibit Antioxidant, antifungal, anti tumoral and antibacterial bioactivity. The objective of this study is to describe the antibacterial activity of 4 extracts of Holoturia. Sp [sea cucumber], collected from Hengam Island of Persian Gulf. Methanol, hexane, aqueous and chloroform extracts from body wall tissue of the sea cucumber were screened for antibacterial activity against three strains of Escherichia coli Top 10 F', TG1 and K12 using disc diffusion and broth microdilution tests methods. The growth of all these strains were inhibited using concentration from 0.78 to 100 mg/ml of methanol, hexan and chloroform extracts. Among the extracts just methanol and chloroform with 100 mg/ml had bactericidal effect on TG1 and K12 strains. On the other hand, Aqueous extract had induced growth in of the all strains. The results suggest the possibility of applying sea cucumber as source of potential anti bacterial agents, whose compounds can be good candidates to make antibiotic products

Forward modeling of the coumarin antifungals; SPR/SAR based perspective

Although, coumarins are a group of compounds which are naturally found in some plants, they can be synthetically produced as well. Because of their diverse derivatives, origin and properties most of them can be used for medicinal purposes. For example, they can be used against fungal diseases or in studying structure and biological properties of antifungal agents to discover new compounds with the similar activity. A Structure Property/Activity Relationship [SAR] can be utilized in prediction of biological activity of desired molecules. In order to represent a relationship between the physicochemical properties of coumarin compounds and their biological activities, 68 coumarins and coumarin derivatives with already reported antifungal activities were selected ' and eleven attributes were generated. The descriptors were used to perform artificial neural network [ANN] and to build a model for predicting effectiveness of the new ones. The correlation coefficient between the experimental and the predicted MIC values pertaining to all the coumarins was O.984. This study paves the way for further researches about antifungal activity of coumarins, and offers a powerful tool in modeling and prediction of their bioactivities

Buthionine sulfoximine inhibits cytopathic effects and apoptosis induced by infection with AIK-HDC strain of measles virus

Measles virus [MV] is a highly contagious agent which causes a major health problem in developing countries. We studied the effect of buthionine sulfoximine [BSO] on the replication of an AIKHDC strain of MV and its induced apoptosis in Vero cell lines. In this study, toxicity of BSO on Vero cells was investigated first, resulted in determination of sub-lethal or non-toxic concentration zone of BSO for cells. Next, anti-viral effect of BSO at various time limits was evaluated and virus titer was determined at each stage either as 50% tissue culture infective dose [TCID] 50 or by plaque assay method. Using specific anti-measles IgG, anti-viral effect of BSO on MV replication cycle was evaluated through indirect immunofluorescence assay, meanwhile presence of viral RNA was investigated by RT-PCR and gel electrophoresis. According to the experiments, BSO, at concentration of 50 microM, markedly inhibited the cytopathic effect [CPE] induced by MV. BSO also significantly inhibited apoptosis induced by MV. BSO either influences replication of MV genome, or may inhibit virion formation. These results suggest that the inhibition of CPE and apoptosis by BSO induced by MV may be associated with the effect of BSO on viral RNA genome. Therefore, it is suggested that MV infections can induce apoptosis through the activation of a common pathway that can be inhibited by BSO