Evaluation of Antibacterial Activities of Fractions from Ethanol-Extracted Residues of Piper guineense Leaves on Gram Negative Clinical Isolate

The problem of drug resistance to orthodox antimicrobial agents has remained a setback in the treatment of bacterial infections in the modern society. Adverse effects, coupled with scarcity and high cost of orthodox drugs have necessitated interest in the search, development and use of antibacterial agents from plant origin. Piper guineense is claimed in traditional medicine as a remedy for gram negative organism-transmitted infections. The leaves of Piper guineense plant was collected, washed, dried at room temperature and pulverized. The plant material was extracted with 80% ethanol. The ethanol-extracted residue was subjected to fractionation. Seventeen fractions were obtained, and were pooled together based on their Rf values into five pooled-fractions labeled: PF-1, PF-2, PF-3, PF-4, PF-5. Both the ethanol and fraction extracts were subjected to phytochemical analysis, preliminary antibacterial screening, minimum inhibitory and minimum bactericidal concentrations determination using both clinical isolates and type culture organisms. The yield of ethanol-extracted residue was low (21.08g) when compared to the amount of pulverized plant material (500g). Phytochemical analysis revealed the presence of flavonoids, alkaloids and terpenoids in all the extracts. The extracts produced statistically significant lower zone of inhibition (p<0.05) when compared with the standard drug (amoxicillin), it also demonstrated activity against test organisms used in the study. The findings of this study demonstrated that ethanol leaf extract of Piper guineense possess antibacterial activities, therefore justifies the traditional claim of the plant.

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SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL EVALUATION OF 3-FORMYL INDOLE BASED SCHIFF BASES

Journal of Biomedical and Pharmaceutical Research ◽

10.32553/jbpr.v7i6.561 ◽

2018 ◽

Vol 7 (6) ◽

Author(s):

Singh Gurvinder ◽

Singh Prabhsimran ◽

Dhawan R. K.

Keyword(s):

Antimicrobial Activity ◽

Spectral Analysis ◽

Schiff Bases ◽

Antimicrobial Agents ◽

Biological Evaluation ◽

Fungal Strain ◽

Bacterial Strains ◽

Standard Drug ◽

Gram Negative ◽

E Coli

In order to develop new antimicrobial agents, a series of 3-formyl indole based Schiff bases were synthesized by reacting 3-formyl indole(indole-3-carboxaldehyde) with substituted aniline taking ethanol as solvent. The reaction was carried in the presence of small amount of p-toluene sulphonic acid as catalyst.All the synthesized compounds were characterized by IR, 1H-NMR spectral analysis. All the synthesized compounds were evaluated for antimicrobial activity against two gram positive bacterial strains (B. subtilisand S. aureus) and two gram negative bacterial strains (P. aeruginosaand E. coli) and one fungal strain (C. albicans). All the synthesized compounds were found to have moderate to good antimicrobial activity. The standard drug amoxicillin, fluconazole were used for antimicrobial activity. Among the synthesized compounds, the maximum antimicrobial activity was shown by compounds GS04, GS07, GS08 and GS10.

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Synthesis, In Vitro and In Silico Studies of Indolequinone Derivatives against Clinically Relevant Bacterial Pathogens

Current Topics in Medicinal Chemistry ◽

10.2174/1568026620666191223110518 ◽

2020 ◽

Vol 20 (3) ◽

pp. 192-208 ◽

Cited By ~ 1

Author(s):

Talita Odriane Custodio Leite ◽

Juliana Silva Novais ◽

Beatriz Lima Cosenza de Carvalho ◽

Vitor Francisco Ferreira ◽

Leonardo Alves Miceli ◽

...

Keyword(s):

In Silico ◽

Bacterial Infections ◽

Antimicrobial Agents ◽

Mass Spectrometry Analysis ◽

World Health ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Dione Derivative ◽

In Silico Studies

Background: According to the World Health Organization, antimicrobial resistance is one of the most important public health threats of the 21st century. Therefore, there is an urgent need for the development of antimicrobial agents with new mechanism of action, especially those capable of evading known resistance mechanisms. Objective: We described the synthesis, in vitro antimicrobial evaluation, and in silico analysis of a series of 1H-indole-4,7-dione derivatives. Methods: The new series of 1H-indole-4,7-diones was prepared with good yield by using a copper(II)- mediated reaction between bromoquinone and β-enamino ketones bearing alkyl or phenyl groups attached to the nitrogen atom. The antimicrobial potential of indole derivatives was assessed. Molecular docking studies were also performed using AutoDock 4.2 for Windows. Characterization of all compounds was confirmed by one- and two-dimensional NMR techniques 1H and 13C NMR spectra [1H, 13C – APT, 1H x 1H – COSY, HSQC and HMBC], IR and mass spectrometry analysis. Results: Several indolequinone compounds showed effective antimicrobial profile against Grampositive (MIC = 16 µg.mL-1) and Gram-negative bacteria (MIC = 8 µg.mL-1) similar to antimicrobials current on the market. The 3-acetyl-1-(2,5-dimethylphenyl)-1H-indole-4,7-dione derivative exhibited an important effect against different biofilm stages formed by a serious hospital life-threatening resistant strain of Methicillin-Resistant Staphylococcus aureus (MRSA). A hemocompatibility profile analysis based on in vitro hemolysis assays revealed the low toxicity effects of this new series. Indeed, in silico studies showed a good pharmacokinetics and toxicological profiles for all indolequinone derivatives, reinforcing their feasibility to display a promising oral bioavailability. An elucidation of the promising indolequinone derivatives binding mode was achieved, showing interactions with important sites to biological activity of S. aureus DNA gyrase. These results highlighted 3-acetyl-1-(2-hydroxyethyl)-1Hindole- 4,7-dione derivative as broad-spectrum antimicrobial prototype to be further explored for treating bacterial infections. Conclusion: The highly substituted indolequinones were obtained in moderate to good yields. The pharmacological study indicated that these compounds should be exploited in the search for a leading substance in a project aimed at obtaining new antimicrobials effective against Gram-negative bacteria.

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Synthesis, in silico pharmacokinetics and biological evaluation of some new thiazolidinedione as PPAR-γ agonists and antibacterial agents

Letters in Drug Design & Discovery ◽

10.2174/1570180818666210427102554 ◽

2021 ◽

Vol 18 ◽

Author(s):

Zohor Mohammad Mahdi Alzhrani ◽

Mohammad Mahboob Alam ◽

Syed Nazreen

Keyword(s):

Antibacterial Agents ◽

Antimicrobial Agents ◽

Antibacterial Activities ◽

Biological Evaluation ◽

New Drugs ◽

Diabetic Patients ◽

Spectroscopic Techniques ◽

Standard Drug ◽

Ppar Γ

Background: The frequent uses of antimicrobial agents to treat infections in diabetic patients make them more drug resistance than non diabetic patients which accounts for higher mortality rate of diabetic patients. Therefore, it is a necessity today to synthesize new drugs with dual mode of action as antidiabetic and antibacterial agents. In the present work, new derivatives containing thiazolidinedione and 1,3,4-oxadiaozle have been synthesized and screened for PPAR-γ and antibacterial activities. Methods: Compound 5-12 have been synthesized from 2-methoxy benzaldehyde and thiazolidinedione and characterized using different spectroscopic techniques such as IR, NMR and mass spectrometry. These compounds were tested for in vitro PPAR-γ transactivation, PPAR-γ gene expression and antibacterial activities. Finally molecular docking was carried out to see the binding interactions of molecules with the target protein. Results: All the compounds follow Lipinski rule suggesting the synthesized derivatives have good drug likeness properties. Compound 11 and 12 exhibited promising PPAR-γ transactivation with 73.69% and 76.50%, respectively as well as showed significant antibacterial activity with comparable MIC of 3.12 μg/disc to standard drug amoxicillin. The docking result was found to be in consistent with the in vitro PPAR-γ transactivation results. Conclusion: Compounds 11 and 12 can be further investigated as lead molecules for the development of new and effective antidiabetic and antibacterial agents.

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Antibacterial Potential of Aloe weloensis (Aloeacea) Leaf Latex against Gram-Positive and Gram-Negative Bacteria Strains

International Journal of Microbiology ◽

10.1155/2019/5328238 ◽

2019 ◽

Vol 2019 ◽

pp. 1-4

Author(s):

Yohannes Kelifa Emiru ◽

Ebrahim Abdela Siraj ◽

Tekleab Teka Teklehaimanot ◽

Gedefaw Getnet Amare

Keyword(s):

Antibacterial Activity ◽

Bacterial Infections ◽

Inhibition Zone ◽

Antibacterial Activities ◽

Maximum Activity ◽

New Drugs ◽

Diffusion Method ◽

Bacterial Strains ◽

Gram Positive ◽

Gram Negative

Objective. To evaluate the antibacterial effects of the leaf latex of Aloe weloensis against infectious bacterial strains. Methods. The leaf latex of A. weloensis at different concentrations (400, 500, and 600 mg/ml) was evaluated for antibacterial activities using the disc diffusion method against some Gram-negative species such as Escherichia coli (ATCC 14700) and Pseudomonas aeruginosa (ATCC 35619) and Gram-positive such as Staphylococcus aureus (ATCC 50080) and Enterococcus fecalis (ATCC 4623). Results. The tested concentrations of the latex ranging between 400 and 600 mg·mL−1 showed significant antibacterial activity against bacterial strain. The highest dose (600 mg/ml) of A. weloensis leaf latex revealed the maximum activity (25.93 ± 0.066 inhibition zone) followed by the dose 500 mg/ml against S. aureus. The lowest antibacterial activity was observed by the concentration 400 mg/ml (5.03 ± 0.03) against E. coli. Conclusion. The results of the present investigation suggest that the leaf latex of A. weloensis can be used as potential leads to discover new drugs to control some bacterial infections.

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Cryo-electron Microscopy Structure of the Acinetobacter baumannii 70S Ribosome and Implications for New Antibiotic Development

mBio ◽

10.1128/mbio.03117-19 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 8

Author(s):

Christopher E. Morgan ◽

Wei Huang ◽

Susan D. Rudin ◽

Derek J. Taylor ◽

James E. Kirby ◽

...

Keyword(s):

Electron Microscopy ◽

Acinetobacter Baumannii ◽

Bacterial Infections ◽

Bound States ◽

Antimicrobial Agents ◽

Gram Negative ◽

Content Type ◽

Antibiotic Development ◽

Cryo Electron Microscopy ◽

70S Ribosome

ABSTRACT Antimicrobial resistance is a major health threat as it limits treatment options for infection. At the forefront of this serious issue is Acinetobacter baumannii, a Gram-negative opportunistic pathogen that exhibits the remarkable ability to resist antibiotics through multiple mechanisms. As bacterial ribosomes represent a target for multiple distinct classes of existing antimicrobial agents, we here use single-particle cryo-electron microscopy (cryo-EM) to elucidate five different structural states of the A. baumannii ribosome, including the 70S, 50S, and 30S forms. We also determined interparticle motions of the 70S ribosome in different tRNA bound states using three-dimensional (3D) variability analysis. Together, our structural data further our understanding of the ribosome from A. baumannii and other Gram-negative pathogens and will enable structure-based drug discovery to combat antibiotic-resistant bacterial infections. IMPORTANCE Acinetobacter baumannii is a severe nosocomial threat largely due to its intrinsic antibiotic resistance and remarkable ability to acquire new resistance determinants. The bacterial ribosome serves as a major target for modern antibiotics and the design of new therapeutics. Here, we present cryo-EM structures of the A. baumannii 70S ribosome, revealing several unique species-specific structural features that may facilitate future drug development to combat this recalcitrant bacterial pathogen.

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Tristemma hirtumand Five Other Cameroonian Edible Plants with Weak or No Antibacterial Effects Modulate the Activities of Antibiotics against Gram-Negative Multidrug-Resistant Phenotypes

The Scientific World JOURNAL ◽

10.1155/2018/7651482 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12

Author(s):

Gaëlle S. Nguenang ◽

Armelle T. Mbaveng ◽

Aimé G. Fankam ◽

Hermione T. Manekeng ◽

Paul Nayim ◽

...

Keyword(s):

Antibacterial Activities ◽

Multidrug Resistant ◽

Phytochemical Analysis ◽

Edible Plants ◽

Phytochemical Screening ◽

Antibacterial Effects ◽

Gram Negative ◽

Microdilution Method ◽

Raphia Hookeri

In order to contribute to the fight against infectious diseases, thein vitroantibacterial activity and the antibiotic-potentiating effects ofTristemma hirtumand five other Cameroonian edible plants have been evaluated against Gram-negative multidrug-resistant (MDR) phenotypes. The microdilution method was used to evaluate the bacterial susceptibility of the extracts and their combination to common antibiotics. The phytochemical screening of the extracts was carried out according to standard methods. Phytochemical analysis of the extracts revealed the presence of alkaloids, triterpenes, steroids, and polyphenols, including flavonoids in most of the tested extracts. The entire tested extracts showed moderate (512 μg/mL ≤ MIC ≤ 2048 μg/mL) to weak (MIC > 2048 μg/mL) antibacterial activities against the tested bacteria. Furthermore, extracts of leaf ofTristemma hirtumand pericarpsofRaphia hookeri(at their MIC/2 and MIC/4) strongly potentiated the activities of all antibiotics used in the study, especially those of chloramphenicol (CHL), ciprofloxacin (CIP), kanamycin (KAN), and tetracycline (TET) against 70% (7/10) to 100% (10/10) of the tested MDR bacteria, with the modulating factors ranging from 2 to 128. The results of this study suggest that extracts from leaves ofTristemma hirtumand pericarps ofRaphia hookerican be sources of plant-derived products with antibiotic modifying activity.

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Antibacterial Screening of some Heterocyclic Compounds Containing Quinoline Nucleus

International Letters of Chemistry Physics and Astronomy ◽

10.18052/www.scipress.com/ilcpa.76.27 ◽

2017 ◽

Vol 76 ◽

pp. 27-40

Author(s):

Shipra Baluja ◽

Nilesh Godvani ◽

Sumitra Chanda

Keyword(s):

Heterocyclic Compounds ◽

Antibacterial Activities ◽

Diffusion Method ◽

Spectroscopic Methods ◽

Gram Negative Bacteria ◽

Gram Negative ◽

H Nmr ◽

Antibacterial Screening ◽

Derivatives Of ◽

Agar Well Diffusion Method

In this work, some novel derivatives of Cyanopyridines and Isoxazoles were synthesized using Vilsmeier-Haack reagent and their structures were confirmed by FTIR, 1H NMR and mass spectroscopic methods. The antibacterial activities of these synthesized compounds were studied in DMSO and DMF by agar well diffusion method against some Gram positive and Gram negative bacteria. It is observed that activity depends upon three S: solvent, strain and structure.

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Investigation of the Biochemical and Ultrastructural Mechanisms Underlying the Antimicrobial Activity of Mimusops spp. Extracts

Baghdad Science Journal ◽

10.21123/bsj.2020.17.2.0452 ◽

2020 ◽

Vol 17 (2) ◽

pp. 0452

Author(s):

Mahmoud S.M. Mohamed ◽

Gehad Abdelmohsen ◽

Gouda T. M. Dawoud

Keyword(s):

Bacterial Infections ◽

High Performance ◽

Antimicrobial Agents ◽

Antimicrobial Effect ◽

Inhibition Zone ◽

Antibacterial Activities ◽

Ultrastructural Changes ◽

Bacterial Strains ◽

Leaf Extracts ◽

Traditional Medicines

Antibiotic resistance is the major growing threat facing the pharmacological treatment of bacterial infections. Therefore, bioprospecting the medicinal plants could provide potential sources for antimicrobial agents. Mimusops, the biggest and widely distributed plant genus of family Sapotaceae, is used in traditional medicines due to its promising pharmacological activities. This study was conducted to elucidate the antimicrobial effect of three unexplored Mimusops spp. (M. kummel, M. laurifolia and M. zeyheri). Furthermore, the mechanisms underlying such antibacterial activity were studied. The Mimusops leaf extracts revealed significant antibacterial activities against the five tested bacterial strains with a maximum inhibition zone diameter of 22.0 mm against B. subtilis compared with standard antibiotic ciprofloxacin. The minimal inhibitory and bactericidal concentration values against tested Gram-positive and Gram-negative bacterial strains ranged from 3.15-12.5 µg/ml. However, weak antifungal effect was recorded against Candida albicans with MIC value ˃25 µg/ml. The 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay showed that M. caffra was the best antioxidant (IC50=14.75±0.028 µg/ml), while M. laurifolia was the least one (IC50=34.22±0.014 µg/ml). The phenolics in plant leaves extracts were identified and quantified by high performance liquid chromatography (HPLC) which revealed the presence of seven phenolic acids and four flavonoids. The abundant phenolic compounds were rutin (5.216±0.067 mg/g dried wt.) and gallic acid (0.296±0.068 mg/g) followed by myricetin (0.317±0.091 mg/g) then kaempferol (0.113±0.049 mg/g) as flavonoids. The antibacterial mechanism of M. laurifolia extract, as a representative species, induces ultrastructural changes in the model bacterium Staphylococcus aureus with cell wall and plasma membrane lysis as revealed by transmission electron microscopy. Overall, Mimusops species (M. laurifolia, M. kummel and M. zeyheri) are promising natural alternative sources for antimicrobial agents.

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Bacteriocins, Antimicrobial Peptides from Bacterial Origin: Overview of Their Biology and Their Impact against Multidrug-Resistant Bacteria

Microorganisms ◽

10.3390/microorganisms8050639 ◽

2020 ◽

Vol 8 (5) ◽

pp. 639 ◽

Cited By ~ 13

Author(s):

Alexis Simons ◽

Kamel Alhanout ◽

Raphaël E. Duval

Keyword(s):

Antimicrobial Resistance ◽

Bacterial Infections ◽

Antimicrobial Agents ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Gram Negative Bacteria ◽

Multidrug Resistant Bacteria ◽

Gram Negative ◽

Gram Positive Bacteria ◽

Further Development

Currently, the emergence and ongoing dissemination of antimicrobial resistance among bacteria are critical health and economic issue, leading to increased rates of morbidity and mortality related to bacterial infections. Research and development for new antimicrobial agents is currently needed to overcome this problem. Among the different approaches studied, bacteriocins seem to be a promising possibility. These molecules are peptides naturally synthesized by ribosomes, produced by both Gram-positive bacteria (GPB) and Gram-negative bacteria (GNB), which will allow these bacteriocin producers to survive in highly competitive polymicrobial environment. Bacteriocins exhibit antimicrobial activity with variable spectrum depending on the peptide, which may target several bacteria. Already used in some areas such as agro-food, bacteriocins may be considered as interesting candidates for further development as antimicrobial agents used in health contexts, particularly considering the issue of antimicrobial resistance. The aim of this review is to present an updated global report on the biology of bacteriocins produced by GPB and GNB, as well as their antibacterial activity against relevant bacterial pathogens, and especially against multidrug-resistant bacteria.

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Antimicrobial Resistance in the Intensive Care Unit

Journal of Intensive Care Medicine ◽

10.1177/0885066615619895 ◽

2016 ◽

Vol 32 (1) ◽

pp. 25-37 ◽

Cited By ~ 58

Author(s):

Shawn H. MacVane

Keyword(s):

Intensive Care ◽

Antimicrobial Resistance ◽

Bacterial Infections ◽

Antimicrobial Agents ◽

Treatment Options ◽

Hospital Costs ◽

High Morbidity ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Gram Negative Organisms

Bacterial infections are a frequent cause of hospitalization, and nosocomial infections are an increasingly common condition, particularly within the acute/critical care setting. Infection control practices and new antimicrobial development have primarily focused on gram-positive bacteria; however, in recent years, the incidence of infections caused by gram-negative bacteria has risen considerably in intensive care units. Infections caused by multidrug-resistant (MDR) gram-negative organisms are associated with high morbidity and mortality, with significant direct and indirect costs resulting from prolonged hospitalizations due to antibiotic treatment failures. Of particular concern is the increasing prevalence of antimicrobial resistance to β-lactam antibiotics (including carbapenems) among Pseudomonas aeruginosa and Acinetobacter baumannii and, recently, among pathogens of the Enterobacteriaceae family. Treatment options for infections caused by these pathogens are limited. Antimicrobial stewardship programs focus on optimizing the appropriate use of currently available antimicrobial agents with the goals of improving outcomes for patients with infections caused by MDR gram-negative organisms, slowing the progression of antimicrobial resistance, and reducing hospital costs. Newly approved treatment options are available, such as β-lactam/β-lactamase inhibitor combinations, which significantly extend the armamentarium against MDR gram-negative bacteria.

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