scholarly journals A scaffolded approach to unearth potential antibacterial components from epicarp of Malaysian Nephelium lappaceum L.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ali Asghar ◽  
Yong Chiang Tan ◽  
Mohammad Zahoor ◽  
Syafiq Asnawi Zainal Abidin ◽  
Yoon-Yen Yow ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Dynamics Simulation ◽  
Significant Activity ◽  
Antibacterial Compounds ◽  
Chemical Profiling ◽  
Nephelium Lappaceum ◽  
Medicinal Use ◽  
Chaperone Dnak ◽  
Potential Alternative ◽  
Alternative Sources

AbstractThe emergence and spread of antimicrobial resistance have been of serious concern to human health and the management of bacterial infectious diseases. Effective treatment of these diseases requires the development of novel therapeutics, preferably free of side effects. In this regard, natural products are frequently conceived to be potential alternative sources for novel antibacterial compounds. Herein, we have evaluated the antibacterial activity of the epicarp extracts of the Malaysian cultivar of yellow rambutan fruit (Nephelium lappaceum L.) against six pathogens namely, Bacillus subtilis, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Pseudomonas aeruginosa, Klebsiella pneumoniae and Salmonella enterica. Among a series of solvent extracts, fractions of ethyl acetate and acetone have revealed significant activity towards all tested strains. Chemical profiling of these fractions, via HPLC, LC–MS and GC–MS, has generated a library of potentially bioactive compounds. Downstream virtual screening, pharmacological prediction, and receptor-ligand molecular dynamics simulation have eventually unveiled novel potential antibacterial compounds, which can be extracted for medicinal use. We report compounds like catechin, eplerenone and oritin-4-beta-ol to be computationally inhibiting the ATP-binding domain of the chaperone, DnaK of P. aeruginosa and MRSA. Thus, our work follows the objective to propose new antimicrobials capable of perforating the barrier of resistance posed by both the gram positives and the negatives.

scholarly journals Chromatographic Analyses, Virtual Screening and Pharmacokinetics of Yellow Malaysian Rambutan (Nephelium lappaceum L.) Fruit Epicarp Extracts Reveal Potential Antibacterial Compounds

2020 ◽  
Author(s):  
Ali Asghar ◽  
Yong Chiang Tan ◽  
Mohammad Zahoor ◽  
Syafiq Asnawi ◽  
Yoon-Yen Yow ◽  
...  
Keyword(s):  
Virtual Screening ◽  
Streptococcus Pyogenes ◽  
Dynamics Simulation ◽  
Significant Activity ◽  
Antibacterial Compounds ◽  
Chemical Profiling ◽  
Nephelium Lappaceum ◽  
Medicinal Use ◽  
Potential Alternative ◽  
Alternative Sources

Abstract The emergence and spread of antimicrobial resistance have been of serious concern on human health and the management of bacterial infectious diseases. Effective treatment of these diseases requires the development of novel therapeutics, preferably free of side effects. In this regard, natural products are frequently conceived to be potential alternative sources for novel antibacterial compounds. Herein, we have evaluated the antibacterial activity of the epicarp extracts of the Malaysian cultivar of yellow rambutan fruit (Nephelium lappaceum L.) against six pathogens namely, Bacillus subtilis, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Pseudomonas aeruginosa, Klebsiella pneumoniae and Salmonella enterica. Among a series of solvent extracts, fractions of ethyl acetate and acetone have revealed significant activity towards all tested strains. Chemical profiling of these fractions, via HPLC, LC-MS and GC-MS, has generated a library of potential bioactive compounds. Downstream virtual screening, pharmacological prediction, and receptor-ligand molecular dynamics simulation have eventually unveiled novel potential antibacterial compounds, which can be extracted for medicinal use. To this end, we report novel mechanistic aspects of these compounds in competitively inhibiting the ATP-binding domain of the DnaK chaperone of P. aeruginosa and MRSA. Our work takes a step forward to discover antimicrobials capable of perforating the barrier of resistance posed by both the gram positives and the negatives.

scholarly journals Antibiotic Susceptibility of Streptococcus Pyogenes Isolated from Respiratory Tract Infections in Dakar, Senegal

2013 ◽  
Vol 6 ◽  
pp. MBI.S12996 ◽  
Author(s):  
Makhtar Camara ◽  
Assane Dieng ◽  
Cheikh Saad Bouh Boye
Keyword(s):  
Respiratory Tract ◽  
Streptococcus Pyogenes ◽  
Respiratory Tract Infections ◽  
Group A Streptococcus ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Group A ◽  
Potential Alternative ◽  
Tract Infections ◽  
Standard Disk

Group A Streptococcus (GAS) is one of the major causes of respiratory tract infections. The objectives of this study were to identify isolates of S. pyogenes obtained from respiratory tract infections, and to assess their susceptibility to several antibiotics. A total of 40 strains were isolated and their susceptibility to 17 antibiotics was tested using a standard disk diffusion method. The minimum inhibitory concentrations (MICs) were determined using the E-test. All isolates were sensitive to β-lactam antibiotics including penicillin, amoxicillin, and cephalosporins. Macrolides remain active with the exception of spiramycin, which showed reduced susceptibility. Out of the 40 isolates, 100% of the isolates were resistant to tetracycline. Interestingly, isolates were sensitive to chloramphenicol, teicoplanin, vancomycine, and levofloxacin, providing potential alternative choices of treatment against infections with S. pyogenes.

scholarly journals Isolation, Characterization and Antibacterial Activity of Ergosta-5, 7, 22-triene-3β, 14α – diol (22Z) from Kenyan Ganoderma lucidum

2020 ◽  
pp. 48-57
Author(s):  
Ebrahim Sande ◽  
Danstone Lilechi Baraza ◽  
Selline Ooko ◽  
Peter Kuloba Nyongesa
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Streptococcus Pyogenes ◽  
Ganoderma Lucidum ◽  
Methicillin Resistance ◽  
Hexane Extract ◽  
Diffusion Method ◽  
Significant Activity ◽  
Disc Diffusion ◽  
Disc Diffusion Method

Aims: To determine the chemical composition and antibacterial activity of Kenyan Ganoderma lucidum. Study Design: Structural determination of the isolated compound was done using spectral evidences and in comparison with literature. The antibacterial properties of the compound was done using disc diffusion method. Place and Duration of Study: Department of Pure and Applied Chemistry, Masinde Muliro University of Science and Technology, between January and November, 2019. Methodology: Sequential extraction of dried samples of Kenyan G. lucidum were done using solvents hexane, ethyl acetate and methanol. Chromatographic separation of hexane extract of Ganoderma lucidum was done using spectroscopic data. The compound was assayed against Escherichia coli, Klebsiella pneumoniae, Methicillin–Resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Streptococcus pyogenes. Standard antibiotic namely; ampicillin was used as the control. Disc diffusion method was used and zones of inhibition, after respective incubation periods, were used to quantify antibacterial activity. Results: From hexane extract of Ganoderma lucidum, Ergosta-5, 7, 22-triene-3β, 14α – diol (22Z) was isolated. Ethylacetate and methanol extracts produced a mixture of complex compounds. Ergosta-5,7,22-triene-3β,14α-diol (22Z) exhibited significant activity against Methicillin-Resistance Staphylococcus aureus (MRSA) (p=0.022) and Streptococcus pyogenes (p = 0.05). The most sensitive microbe was Streptococcus pyogenes. Conclusion: One major compound, Ergosta-5, 7, 22-triene-3β, 14α – diol (22Z) was isolated, characterized and antibacterial activity determined.

scholarly journals Uji efek antibakteri ekstrak kulit kayu manis (Cinnamomum burmannii) terhadap Escherichia coli dan Streptococcus pyogenes

2016 ◽  
Vol 4 (1) ◽  
Author(s):  
Noviano B. Reppi ◽  
Christi Mambo ◽  
Jane Wuisan
Keyword(s):  
Escherichia Coli ◽  
Streptococcus Pyogenes ◽  
Antibacterial Effect ◽  
Bark Extract ◽  
Inhibitory Zone ◽  
Antibacterial Compounds ◽  
Cinnamon Bark ◽  
E Coli ◽  
Inhibition Zones ◽  
Cinnamomum Burmannii

Abstract: Cinnamon (Cinnamomum burmannii) is a natural substance that has been known as one of the spices, but later known as traditional medicine. Cinnamon bark contains several antibacterial compounds, such as eugenol and cinnamaldehyde. There were two species of bacteria used in this study, Escherichia coli and Streptococcus pyogenes. These bacteria represent negative Gram bacteria and positive gram bacteria. The study aimed to determine antibacterial effect of cinamon bark againts E.coli and S.pyogenes by measuring the diameters of the inhibition zones. Cinamon bark samples were taken from Kaneyan, South Minahasa, and then be extracted by maceration using 80% etanol. The results showed that the total diameter of the inhibitory zone of Cinamon bark extract against E.coli was 43 mm with an average of 14,3 mm, and the total diameter of the inhibitory zone against S.pyogenes was 75 mm with an average of 25 mm. Conclusion: Cinamon bark extract had antibacterial effect against E Escherichia coli and Streptococcus pyogenes. Keywords: cinamon bark, escherichia coli, streptococcus pyogenes,antibacterial effect. Abstrak: Kayu manis (Cinnamomum burmannii) merupakan bahan alami yang selama ini hanya dikenal sebagai bumbu dalam masakan, tetapi ternyata memiliki khasiat obat. Kulit kayu manis mengandung beberapa senyawa yang bersifat antibakteri, seperti eugenol dan cinnamaldehyde. Bakteri Escherichia coli dan Streptococcus pyogenes merupakan bakteri yang digunakan didalam peneilitian ini. Kedua bakteri ini mewakili bakteri Gram negatif dan positif. Penelitian ini bertujuan untuk mengetahui efek antibakteri kulit kayu manis terhadap E. coli dan S. pyogenes, yang dinilai dari besarnya zona hambat yang terbentuk. Jenis penelitian ini eksperimental dengan metode sumuran Kirby-Bauer. Sampel kulit kayu manis diambil dari daerah Kaneyan Kabupaten Minahasa Selatan, kemudian diekstraksi dengan metode maserasi menggunakan pelarut etanol 80%. Hasil penelitian memperlihatkan diameter zona hambat total dari ekstrak kulit kayu manis terhadap E. coli sebesar 43mm dengan rerata 14,3mm, dan terhadap S. pyogenes diameter zona hambat total 75mm dengan rerata 25mm. Simpulan: Ekstrak kulit kayu manis memiliki efek antibakteri dalam menghambat pertumbuhan Escherichia coli dan Streptococcus pyogenesKata kunci: kulit kayu manis, Escherichia coli, Streptococcus pyogenes, antibakteri

scholarly journals Mineralogical and Geochemical Characteristics of Lithium and Rare Earth Elements in High-Sulfur Coal from the Donggou Mine, Chongqing, Southwestern China

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 627
Author(s):  
Jianhua Zou ◽  
Longfei Cheng ◽  
Yuanchen Guo ◽  
Zhengcheng Wang ◽  
Heming Tian ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Raw Materials ◽  
Geochemical Characteristics ◽  
Critical Elements ◽  
Geological Factors ◽  
Potential Alternative ◽  
Geological Factor ◽  
Alternative Sources ◽  
Coal Measures

Coal and coal by-products are considered as the potential raw materials for critical elements (e.g., rare earth elements, Li, Ga, Ge, etc.), which have attracted much attention in recent years. The purpose of this study is to investigate the mineralogical and geochemical characteristics, and controlling geological factors of lithium and rare earth elements in the Lopingian (Wujiaping Formation) coal from the Donggou Mine, southeastern Chongqing Coalfield, China. Results indicate that lithium and rare earth elements are significantly enriched in the Donggou coals, which could be new potential alternative sources for critical elements. Concentrations of lithium and rare earth elements in the Donggou coals gradually increase from top to bottom. Lithium is mainly associated with kaolinite, while rhabdophane, florencite, goyazite, and xenotime are the main hosts of rare earth elements. The controlling geological factor is the groundwater leaching of underlying tuff, and to a lesser extent, the terrigenous clastic materials input from the top layer of the Kangdian Upland. This study provides mineralization information for lithium and rare earth elements exploration in coal measures.

scholarly journals Opuntia Ficus-Indica L. Miller (Palma Forrageira) as an Alternative Source of Cellulose for Production of Pharmaceutical Dosage Forms and Biomaterials: Extraction and Characterization

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1124 ◽  
Author(s):  
Amaro César Lima de Assis ◽  
Larissa Pereira Alves ◽  
João Paulo Tavares Malheiro ◽  
Alana Rafaela Albuquerque Barros ◽  
Edvânia Emannuelle Pinheiro-Santos ◽  
...  
Keyword(s):  
Raw Materials ◽  
Low Cost ◽  
Dosage Forms ◽  
Cellulose Ii ◽  
X Ray Diffraction ◽  
Alternative Source ◽  
Opuntia Ficus Indica ◽  
Pharmaceutical Dosage Forms ◽  
Potential Alternative ◽  
Alternative Sources

Cellulose is among the top 5 excipients used in the pharmaceutical industry. It has been considered one of the main diluents used in conventional and modern dosage forms. Therefore, different raw materials of plant origin have been evaluated as potential alternative sources of cellulose. In this context, Opuntia ficus-indica L. Miller (palma forrageira), a plant of the cactus family that has physiological mechanisms that provide greater productivity with reduced water requirements, is an interesting and unexplored alternative for extracting cellulose. By using this source, we aim to decrease the extraction stages and increase the yields, which might result in a decreased cost for the industry and consequently for the consumer. The aim of this work was to investigate the use of Opuntia ficus-indica L. Miller as a new source for cellulose extraction, therefore providing an efficient, straight forward and low-cost method of cellulose II production. The extraction method is based on the oxidation of the lignins. The obtained cellulose was identified and characterized by spectroscopic methods (FTIR and NMR), X-ray diffraction, thermal analysis (TGA-DTG and DSC) and scanning electron microscopy. The results confirmed the identity of cellulose and its fibrous nature, which are promising characteristics for its use in the industry and a reasonable substrate for chemical modifications for the synthesis of cellulose II derivatives with different physicochemical properties that might be used in the production of drug delivery systems and biomaterials.

scholarly journals Hydrogen Peroxide Production in Streptococcus pyogenes: Involvement of Lactate Oxidase and Coupling with Aerobic Utilization of Lactate

2004 ◽  
Vol 186 (7) ◽  
pp. 2046-2051 ◽  
Author(s):  
Masanori Seki ◽  
Ken-ichiro Iida ◽  
Mitsumasa Saito ◽  
Hiroaki Nakayama ◽  
Shin-ichi Yoshida
Keyword(s):  
Streptococcus Pyogenes ◽  
Oxidase Activity ◽  
Nadh Oxidase ◽  
Soluble Fraction ◽  
The Other ◽  
Significant Activity ◽  
Lactate Oxidase ◽  
Permeabilized Cells ◽  
A Subunit

ABSTRACT Streptococcus pyogenes strains can be divided into two classes, one capable and the other incapable of producing H2O2 (M. Saito, S. Ohga, M. Endoh, H. Nakayama, Y. Mizunoe, T. Hara, and S. Yoshida, Microbiology 147:2469-2477, 2001). In the present study, this dichotomy was shown to parallel the presence or absence of H2O2-producing lactate oxidase activity in permeabilized cells. Both lactate oxidase activity and H2O2 production under aerobic conditions were detectable only after glucose in the medium was exhausted. Thus, the glucose-repressible lactate oxidase is likely responsible for H2O2 production in S. pyogenes. Of the other two potential H2O2-producing enzymes of this bacterium, NADH and α-glycerophosphate oxidase, only the former exhibited low but significant activity in either class of strains. This activity was independent of the growth phase, suggesting that the protein may serve in vivo as a subunit of the H2O2-scavenging enzyme NAD(P)H-linked alkylhydroperoxide reductase. The activity of lactate oxidase was associated with the membrane while that of NADH oxidase was in the soluble fraction, findings consistent with their respective physiological roles, i.e., the production and scavenging of H2O2. Analyses of fermentation end products revealed that the concentration of lactate initially increased with time and decreased on glucose exhaustion, while that of acetate increased during the culture. These results suggest that the lactate oxidase activity of H2O2-producing cells oxidizes lactate to pyruvate, which is in turn converted to acetate. This latter process proceeds presumably via acetyl coenzyme A and acetyl phosphate with formation of extra ATP.

scholarly journals Sutherlandia frutescens (Fabaceae) extracts used for treating tuberculosis do not have high activity against Mycobacterium smegmatis

2017 ◽  
Vol 36 (1) ◽  
Author(s):  
Itumeleng H. Mabusa ◽  
Rachmond Howard ◽  
Peter Masoko
Keyword(s):  
Bioactive Compounds ◽  
Mycobacterium Smegmatis ◽  
High Performance ◽  
Antimycobacterial Activity ◽  
Chemical Profiling ◽  
Aerial Parts ◽  
Medicinal Use ◽  
Tlc Plates ◽  
Ethanol Extracts ◽  
Sutherlandia Frutescens

Sutherlandia frutescens (L) R. Br. contains several essential, bioactive compounds with clinically proven pharmacological activities. Sutherlandia is prescribed for people with tuberculosis but it is still not known what compounds in this plant act against Mycobacterium tuberculosis and its mode of action. This study is aimed at determining if S. frutescens extracts contain antimycobacterial compounds. Aerial parts of S. frutescens were dried, ground and extracted with ethanol, dichloromethane: methanol 1:1 (v/v) and water. The chemical profiling was done using high-performance liquid chromatography-mass spectroscopy (HPLC-MS) and thin layer chromatography (TLC). TLC plates were developed in butanol:acetic acid:water (BAW) to the ratio of 21:6:3; chloroform:methanol:water:formic acid (CMWF1) [60:15:2:1] and (CMWF2) [21:9:1:0.3]. Qualitative antioxidant activity was done, using 2.2-diphenylpacryl-1-hydrazyl (DPPH). Antimycobacterial activity of the plant extracts was evaluated, using micro-dilution and bioautographic methods against Mycobacterium smegmatis. Low antimycobacterial activity against M. smegmatis was observed on the bioautograms. The ethanol extracts contained more compounds compared to water extracts on HPLC-MS chromatographic profiles. The average Minimum Inhibitory Concentration (MIC) values for all the extracts were 0.61 mg/mL units and the DCM:MeOH (1:1) extract had the lowest MIC value of 0.28 mg/mL. The results showed that the plant could be further explored for possible antimycobacterial agents. Low activity was observed, possibly due to low replication of bacilli and non-replicating organisms. The study provides preliminary scientific validation of the traditional medicinal use of this plant. Further studies are required to identify the bioactive compounds in the DCM:MeOH 1:1 extract which showed significant antimycobacterial activities. Research correlation: This article is the original version, of which an Afrikaans translation was made available to provide access to a larger readership, available here: https://doi.org/10.4102/satnt.v36i1.1494

scholarly journals Novel Inhibitors of the Main Protease of SARS-CoV-2 Identified via a Molecular Dynamics Simulation-Guided in Vitro Assay

2020 ◽  
Author(s):  
Jennifer Loschwitz ◽  
Anna Jäckering ◽  
Monika Keutmann ◽  
Maryam Olagunju ◽  
Raphael J. Eberle ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Binding Site ◽  
Drug Repurposing ◽  
Dynamics Simulation ◽  
Significant Activity ◽  
Vitro Assay ◽  
Protease Enzyme ◽  
Main Protease ◽  
Dynamics Simulations

<div>For the COVID-19 pandemic caused by SARS-CoV-2, there are currently no effective drugs or vaccines to treat this coronavirus infection. In this study, we focus on the main protease enzyme of SARS-CoV-2, 3CL pro , which is critical for viral replication. We employ explicit solvent molecular dynamics simulations of about 150 compounds docked into 3CL pro ’s binding site and that had emerged as good main protease ligands from our previous in silico screening of over 1.2 million compounds. By incoporating protein dynamics and applying a range of structural descriptors, such as the ability to form specific contacts with the catalytic dyad residues of 3CL pro and the structural fluctuations of the ligands in the binding site, we are able to further refine our compound selection. Fourteen compounds including estradiol shown to be the most promising based on our calculations were procured and screened against recombinant 3CL pro in a fluorescence assay. Eight of these compounds have significant activity in inhibiting the SARS-CoV-2 main protease. Among these are corilagin, a gallotannin, and lurasidone, an antipsychotic drug, which emerged as the most promising natural product and drug, respectively, and might thus be candidates for drug repurposing for the treatment of COVID-19. In addition, we also tested the inhibitory activity of testosterone, and our results reveal testosterone as possessing moderate inhibitory potency against the 3CL pro enzyme, which may thus provide an explanation why older men are more severely affected by COVID-19.</div>

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