scholarly journals Antimicrobial Applications of Rhamnolipid Biosurfactant Produced from Achromobacter sp. (PS1) Isolate Using Lignocellulosic Hydrolysate

2021 ◽  
Vol 11 (4) ◽  
pp. 4263-4271
Keyword(s):  
Pathogenic Bacteria ◽  
High Surface ◽  
Lower Percentage ◽  
Dilution Method ◽  
Heterogeneous Mixture ◽  
Lignocellulosic Hydrolysate ◽  
Gram Negative ◽  
Surface Activities ◽  
Achromobacter Sp ◽  
Rhamnolipid Biosurfactant

Heterogeneous mixture of partially purified rhamnolipid (RL) produced from Achromobacter sp. (PS1) using lignocellulosic rice straw (RS) sugar hydrolysate medium revealed six different congeners- Rha- C10-C10, Rha-C8-C10/Rha-C10-C8, Rha- C12-C10 / Rha- C10-C12, referring mono-rhamnolipids amounting to total 68.23 % and Rha-Rha-C10-C10, Rha-Rha-C8-C10/Rha-Rha-C10-C8, Rha-Rha-C10-C12/Rha-Rha-C12-C10, referring di-rhamnolipids amounting to 31.73 %, with Mono to Di- RL in the ratio of 2.1:1. This mixture's antimicrobial action containing more mono-rhamnolipids analyzed using broth macro-dilution method exhibited a broad-spectrum antibacterial activity showing ≥ 90 % growth inhibition of both Gram-positive and Gram-negative pathogenic bacteria at MIC ranging from 1.25 mg/mL to 10 mg/mL of total rhamnolipids. This might be due to the more hydrophobic character of mono-rhamnolipids containing a single rhamnosyl group and showing high surface activities. On the other hand, the non-antifungal activity may be attributed to the lower percentage of di-rhamnolipids in the partially purified mixture.

scholarly journals Benzimidazole Schiff base derivatives: synthesis, characterization and antimicrobial activity

BMC Chemistry ◽  
2019 ◽  
Vol 13 (1) ◽  
Author(s):  
Thierry Youmbi Fonkui ◽  
Monisola Itohan Ikhile ◽  
Patrick Berka Njobeh ◽  
Derek Tantoh Ndinteh
Keyword(s):  
Growth Inhibition ◽  
Schiff Bases ◽  
Hela Cells ◽  
Cytotoxic Effect ◽  
Pathogenic Bacteria ◽  
Dilution Method ◽  
Klebsiella Pneumonia ◽  
Resonance Spectroscopy ◽  
Reference Drug ◽  
Gram Negative

Abstract A series of Schiff bases (3.a–f) bearing benzimidazole moiety was successfully synthesized in ethanol by refluxing Oct-2-ynoic acid (1,3-dihydrobenzimidazole-2-ylidene)amide with substituted amines. Fourier transform infrared (FTIR), ultra violet light (UV–VIS), elemental analysis, proton (1H) and carbon (13C) nuclear magnetic resonance spectroscopy were used to characterize the newly synthesized Schiff bases. Micro dilution method was used to determine the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of the Schiff bases, against 14 human pathogenic bacteria (8 Gram negative and 6 Gram positive) and against 7 fungal strains (5 Aspergillus and 2 Fusarium) representatives. Antimalarial activity against Plasmodium falciparum and antitrypanosomal property against Trypanosoma brucei was studied in vitro at a single dose concentration of the Schiff bases. Cytotoxicity of the Schiff bases was assessed against human cervix adenocarcinoma (HeLa) cells. Results obtained show that the newly synthesized Schiff bases are very potent antimicrobial agents. Gram negative bacteria Klebsiella pneumonia and Escherichia coli were more affected on exposure to Compounds 3.c–f (MIC 7.8 µg/mL) which in turn exhibited more antibacterial potency than nalidixic acid reference drug that displayed MICs between 64 and 512 µg/mL against K. pneumonia and E. coli respectively. The test compounds also demonstrated high cytotoxic effect against Aspergillus flavus and Aspergillus carbonarius as they displayed MFC 7.8 and 15.6 µg/mL. Compound 3.c exhibited the highest fungicidal property from this series with MFC alternating between 7.8 and 15.6 µg/mL against the investigated strains. The malarial activity revealed Compounds 3.c and 3.d as the more potent antiplasmodial compounds in this group exhibiting 95% and 85% growth inhibition respectively. The IC50 of Compounds 3.c and 3.d were determined and found to be IC50 26.96 and 28.31 µg/mL respectively. Compound 3.a was the most cytotoxic agent against HeLa cells in this group with 48% cell growth inhibition. Compounds 3.c, 3.d and 3.f were biocompatible with HeLa cells and displayed low toxicity. With a very low cytotoxic effect against HeLa, compound 3.c stands out to be a very good antiparasitic agent and consideration to further evaluate the candidate drug against others cell lines is necessary.

Combination Therapy for Bacterial Pathogens: Naturally Derived Antimicrobial Drugs Augmented with Ulva lactuca Extract

2021 ◽  
Vol 21 ◽  
Author(s):  
Nilushi Indika Bamunuarachchi ◽  
Fazlurrahman Khan ◽  
Young-Mog Kim
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Inhibitory Concentration ◽  
Bacterial Pathogens ◽  
Dilution Method ◽  
Gram Positive ◽  
Antimicrobial Drugs ◽  
Gram Negative ◽  
Hexane Extracts ◽  
Conventional Antibiotics

Background: With the growing incidence of microbial pathogenesis, several alternative strategies have been developed. The number of treatments using naturally (e.g., plants, algae, fungi, bacteria, and animals) derived compounds has increased. Importantly, marine-derived products have become a promising and effective approach to combat the antibiotic resistance properties developed by bacterial pathogens. Furthermore, augmenting the sub-inhibitory concentration of the naturally-derived antimicrobial compounds (e.g., hydroxycinnamic acids, terpenes, marine-derived polysaccharides, phenolic compounds) into the naturally derived extracts as a combination therapy to treat the bacterial infection has not been well studied. Objective: The present study was aimed to prepare green algae Ulva lactuca extract and evaluate its antibacterial activity towards Gram-positive and Gram-negative human pathogenic bacteria. Also, revitalize the antibacterial efficiency of the naturally-derived antimicrobial drugs and conventional antibiotics by augmenting their sub-MIC to the U. lactuca extracts. Methods: Extraction was done using a different organic solvent, and its antibacterial activity was tested towards Gram-positive and Gram-negative pathogens. The minimum inhibitory concentration (MIC) of U. lactuca extracts has been determined towards pathogenic bacteria using the micro broth dilution method. The viable cell counting method was used to determine the minimum bactericidal concentration (MBC). The fractional inhibitory concentration (FIC) assay was utilized to examine the combinatorial impact of sub-MIC of two antibacterial drugs using the micro broth dilution method. The chemical components of the extract were analyzed by GC-MS analysis. Results: Among all the extracts, n-hexane extract was found to show effective antibacterial activity towards tested pathogens with the lowest MIC and MBC value. Furthermore, the n-hexane extracts have also been used to enhance the efficacy of the naturally-derived (derived from plants and marine organisms) compounds and conventional antibiotics at their sub-inhibitory concentrations. Most of the tested antibiotics and natural drugs at their sub-MIC were found to exhibit synergistic and additive antibacterial activity towards the tested bacterial pathogens. Conclusions: The augmenting of U. lactuca n-hexane extracts resulted in synergistic and additive bactericidal effects on Gram-positive and Gram-negative human pathogenic bacteria. The present study shows a new alternative strategy to revitalize the antimicrobial activity of naturally derived compounds for treating human bacterial pathogens.

scholarly journals Bridelia retusa (L.) Spreng. Fruits: Antimicrobial Efficiency and their Phytochemical Constituents

2016 ◽  
Vol 8 (1) ◽  
pp. 33-36 ◽  
Author(s):  
Aniel Kumar OWK ◽  
Mutyala Naidu LAGUDU
Keyword(s):  
Pathogenic Bacteria ◽  
Antimicrobial Activities ◽  
Fungal Species ◽  
Dilution Method ◽  
Phytochemical Analysis ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Antimicrobial Efficiency ◽  
Bridelia Retusa

Antimicrobial analysis of hexane, chloroform, methanol and aqueous extracts of Bridelia retusa fruits was performed by agar well method and minimum inhibitory concentration was determined by serial two-fold dilution method. Seven human pathogenic bacteria species including Gram positive and Gram negative bacteria and three fungal species were used in the study and the results indicated that the Gram positive bacteria and fungi were more sensitive than the Gram negative bacteria, to both solvent and aqueous Bridelia retusa fruit extracts. Moreover, Enterococcus faecalis was found as the most sensitive bacteria, whereas Proteus vulgaris and Aspergillu niger were the most resistant to the tested extracts. Phytochemical analysis of fruits revealed the presence of secondary metabolites like alkaloid, saponins and terpenoids, which have been implicated in antimicrobial activities. Hence, it would be recommended to explore the maximum potential of Bridelia retusa in the medicinal and pharmaceutical field and investigation are endorsed for further application useful in phytomedicine.

An outlook for food sterilization technology: targeting the outer membrane of foodborne gram-negative pathogenic bacteria

2021 ◽  
Vol 42 ◽  
pp. 15-22
Author(s):  
Zhaohuan Zhang ◽  
Zhenhua Huang ◽  
Jinrong Tong ◽  
Qian Wu ◽  
Yingjie Pan ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Pathogenic Bacteria ◽  
Gram Negative ◽  
Food Sterilization

scholarly journals A Facile Synthesis and Studies of Some New Chalcones and Their Derivatives Based on Heterocyclic Ring

2012 ◽  
Vol 9 (4) ◽  
pp. 1897-1905 ◽  
Author(s):  
A. Solankee ◽  
K. Patel ◽  
R. Patel
Keyword(s):  
Inhibitory Concentration ◽  
Guanidine Hydrochloride ◽  
Heterocyclic Ring ◽  
Dilution Method ◽  
Facile Synthesis ◽  
Phenyl Hydrazine ◽  
Gram Negative ◽  
E Coli ◽  
Heterocyclic Aldehydes ◽  
Broth Dilution

Chalcones(6a-f)have been prepared by the condensation of ketone(5)and different aromatic and heterocyclic aldehydes. These chalcones(6a-f)on treatment with guanidine hydrochloride and phenyl hydrazine hydrochloride in presence of alkali give aminopyrimidines(7a-f)and phenylpyrazolines(8a-f)respectively. All the newly synthesized compounds have been characterized on the basis of IR,1HNMR spectral data as well as physical data. Antibacterial activity (minimum inhibitory concentration MIC) against Gram-positiveS. aureusMTCC 96 andS. pyogeneusMTCC 442 and Gram-negativeP. aeruginosaMTCC 1688 andE. coliMTCC 443 bacteria, as well as antifungal acivities (MIC) againstC. albicansMTCC 227,A. nigerMTCC 282 andA. clavatusMTCC 1323 were determined by broth dilution method.

Biosynthesis of Silver Nanoparticles by Punica Granatum Peel Extract and their Biological Activity on different Pathogenic Bacteria

2021 ◽  
Vol 19 (9) ◽  
pp. 38-45
Author(s):  
Hussein H. Al-Turnachy ◽  
Fadhilk. alibraheemi ◽  
Ahmed Abd Alreda Madhloom ◽  
Zahraa Yosif Motaweq ◽  
Nibras Yahya Abdulla
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Biological Activity ◽  
Pathogenic Bacteria ◽  
Punica Granatum ◽  
Gram Positive ◽  
Gram Negative ◽  
Inhibition Zones ◽  
Peel Extract

The present study was included the assessment of the antimicrobial activity of AgNPs synthesized by Punica granatum peel extract against pathogenic bacteria by testing warm aqueous P. granatum peel extract and silver nanoparticles. Punica granatum indicated potency for AgNP extracellular nanobiosynthesis after addition of silver nitrate (AgNO3) 4mM to the extract supernatant, in both concentrations (100mg and 50mg). The biogenic AgNPs showed potency to inhibit both gram-negative and gram-positive bacterial growth. Zons of inhibition in (mm) was lesser in gram-positive than gram-negative bacteria. The resulted phytogenic AgNPs gave higher biological activity than warm aqueous Punica granatum peel extract. The inhibition zone of the phytogenic AgNPs on E. coli reached 17.53, 22.35, and 26.06 mm at (0.1, 0.5, and 1) mg/ml respectively. While inhibition zones of Punica warm aqueous extract reached 5.33, 10.63, and 16.08 mm at the same concentrations. phytogenic AgNPs gave smaller inhibition zones in gram-positive than gram- negative. Cytotoxic activity of the phytogenic AgNPs was assayed in vitro agaist human blood erythrocytes (RBCs), spectroscopic results showed absorbance at 540 nm hemolysis was observed. In general, AgNPs showed least RBCs hemolysis percentage, at 1 mg/ml concentration, hemolysis percentage was (4.50%). This study, concluded that the Punica granatum peel extract has the power of synthses of AgNPs characterized by broad spectrum antimicrobial activity with cyto-toxicity proportional to AgNPs concentration.

The penetration of Human Defensin 5 (HD5) through bacterial outer membrane: Simulation studies

2021 ◽  
Author(s):  
Tadsanee Awang ◽  
Prapasiri Pongprayoon
Keyword(s):  
Pathogenic Bacteria ◽  
Lipid A ◽  
Dominant Role ◽  
Membrane Surface ◽  
Innate Immune ◽  
Hydrophobic Core ◽  
Gram Negative ◽  
Head Groups ◽  
Bacterial Outer Membrane ◽  
Human Defensin 5

Abstract Human α-defensin 5 (HD5) is one of cationic antimicrobial peptides which plays a crucial role in an innate immune system in human body. HD5 shows the killing activity against a broad spectrum of pathogenic bacteria by making a pore in a bacterial membrane and penetrating into a cytosol. Nonetheless, its pore-forming mechanisms remain unclear. Thus, in this work, the constant-velocity steered molecular dynamics (SMD) simulation was used to simulate the permeation of a dimeric HD5 into a gram-negative LPS membrane model. Arginine-rich HD5 is found to strongly interact with a LPS surface. Upon arrival, arginines on HD5 interact with lipid A head groups and then drag these charged moieties down into a hydrophobic core resulting in the formation of water-filled pore. Although all arginines are found to interact with a membrane, R13 and R32 appear to play a dominant role in the HD5 adsorption on a gram-negative membrane. Furthermore, one chain of a dimeric HD5 is required for HD5 adhesion. The interactions of arginine-Lipid A head groups play a major role in adhering a cationic HD5 on a membrane surface and retarding a HD5 passage in the meantime.

Comparative Evaluation of the Sterilization Effect of Six Kinds of Commercial Disinfectants against Four Pathogenic Bacteria

2021 ◽  
Author(s):  
Wenxia Wang ◽  
Xiaoting Liang ◽  
Junxia Zheng ◽  
Qi He
Keyword(s):  
Sodium Hypochlorite ◽  
Peracetic Acid ◽  
Pathogenic Bacteria ◽  
Antibacterial Effect ◽  
Antibacterial Properties ◽  
Water Soluble ◽  
Absolute Ethanol ◽  
Dilution Method ◽  
Clostridium Sporogenes ◽  
Sterilization Effect

Abstract In this work, we systematically investigate the sterilization effect of six kinds of commonly used commercial disinfectants, including the DuPont Virkon disinfectant, peracetic acid disinfectant, sodium hypochlorite, bromogeramine disinfectant, water-soluble allicin, and absolute ethanol, against the Escherichia coli, Staphylococcus aureus, Monilia albican and Clostridium sporogenes. The inhibition zone was used to qualitatively determine the antibacterial effects of the six disinfectants, and then the minimum two-fold dilution method was used to quantitatively determine the minimum inhibitory concentration and minimum bactericidal concentration of the six disinfectants on the four pathogens. The result illustrated that the antibacterial effect of peracetic acid disinfectant is the best, and clostridium sporogenes is the most sensitive to it, followed by bromogermine disinfectant, which can inhibit the four pathogenic bacteria at the concentration recommended by the manufacturer. The antibacterial effect of DuPont Virkon disinfectant, sodium hypochlorite, water-soluble allicin and absolute ethanol is not as good as expected, and cannot inhibit the four kinds of pathogenic bacteria at the recommended concentration. In summary, the antibacterial effect of peracetic acid disinfectant is the strongest, followed by the bromogermine disinfectant, DuPont Virkon disinfectant, sodium hypochlorite and water-soluble allicin. The absolute ethanol exhibits the worst antibacterial properties.

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