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 Synergistic Antibacterial Effects of Polyphenolic Compounds from Olive Mill Wastewater

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Ahmed Tafesh ◽  
Naim Najami ◽  
Jeries Jadoun ◽  
Fares Halahlih ◽  
Herbert Riepl ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Growth Inhibition ◽  
Gallic Acid ◽  
Pathogenic Bacteria ◽  
Olive Mill Wastewater ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Negative ◽  
Olive Mill

Polyphenols or phenolic compounds are groups of secondary metabolites widely distributed in plants and found in olive mill wastewater (OMW). Phenolic compounds as well as OMW extracts were evaluatedin vitrofor their antimicrobial activity against Gram-positive (Streptococcus pyogenesandStaphylococcus aureus) and Gram-negative bacteria (Escherichia coliandKlebsiella pneumoniae). Most of the tested phenols were not effective against the four bacterial strains when tested as single compounds at concentrations of up to 1000 μg mL−1. Hydroxytyrosol at 400 μg mL−1caused complete growth inhibition of the four strains. Gallic acid was effective at 200, and 400 μg mL−1againstS. aureus, andS. pyogenes, respectively, but not against the gram negative bacteria. An OMW fraction called AntiSolvent was obtained after the addition of ethanol to the crude OMW. HPLC analysis of AntiSolvent fraction revealed that this fraction contains mainly hydroxytyrosol (10.3%), verbascoside (7.4%), and tyrosol (2.6%). The combinations of AntiSolvent/gallic acid were tested using the low minimal inhibitory concentrations which revealed that 50/100–100/100 μg mL−1caused complete growth inhibition of the four strains. These results suggest that OMW specific fractions augmented with natural phenolic ingredients may be utilized as a source of bioactive compounds to control pathogenic bacteria.

scholarly journals Evaluation of the Anti-mitotic and Bacteriostatic Activities of the Fruiting Bodies of Pleurotus Ostreatus (Jacq. Ex. Fr) P. Kumm. (Pleurotaceae)

2019 ◽  
Vol 6 (1) ◽  
pp. 39-44
Author(s):  
Ozadheoghene Afieroho ◽  
Elizabeth C. Chukwu ◽  
Osamuyi H. Festus ◽  
Chiazor P. Onyia ◽  
Mikailu Suleiman ◽  
...  
Keyword(s):  
Mitotic Activity ◽  
Aqueous Extract ◽  
Pleurotus Ostreatus ◽  
Ethanol Extract ◽  
Edible Mushroom ◽  
Negative Control ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Klebsiella Pneumonia ◽  
Reference Drug

Edible mushrooms aside being taken as foods, are used in ethnomedicine in the management of various ailments notably tumours and related ailments whose pathophysiology are linked to oxidative stress. This study investigated the anti-mitotic, and antibacterial activities of the aqueous extract of the edible mushroom Pleurotus ostreatus based on ethno-medicine.The Allium cepa anti-mitotic assay model was used for anti-proliferative investigation of the defatted aqueous ethanol extract at concentration range of: 10.00 – 0.08 ng/mL following a two-fold serial dilution approach. Methotrexate (0.25 ng/mL) and portable water were used as reference standard for positive control and negative control respectively. The student t-test was used for statistical analysis (p < 0.05). Antibacterial susceptibility evaluation against clinical isolates of selected pathogenic organisms: Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Staphylococcus aereus, and Bacillus subtilis was done using the Agar dilution method at 1000 and 10 µg/mL. The aqueous extract showed a dose and time dependent anti-mitotic activity with the three higher doses: 10.00, 5.00 and 2.50 ng/mL exhibiting complete inhibition of mitosis which was comparable to the reference drug methotrexate (0.25 ng/mL) after 96 hours incubation period. Although the aqueous extract was not bacteriocidal at the test concentration, a dose dependent bacteriostatic effect against E. coli, and B. subtilis was observed. The observed anti-mitotic activity of this mushroom validates its ethnomedicinal use in the treatment of tumours and related diseases.  

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.

scholarly journals Antibacterial Activities of Some Schiff Bases Involving Thiosemicarbazide and Ketones

2014 ◽  
Vol 26 ◽  
pp. 53-61 ◽  
Author(s):  
S.M.S. Shariar ◽  
M. Jesmin ◽  
M.M. Ali
Keyword(s):  
Antibacterial Activity ◽  
Minimum Inhibitory Concentration ◽  
Schiff Bases ◽  
Cytotoxic Effect ◽  
Pathogenic Bacteria ◽  
Inhibitory Concentration ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
Disc Diffusion ◽  
Disc Diffusion Method

Three Schiff bases derived from thiosemicarbazide and ketones (Vanillin, Benzophenone and Acetophenone) were used to study their antibacterial activities against some pathogenic bacteria by disc diffusion method. Of these, benzophenone thiosemicarbazone showed significant antibacterial activity as compared with that of Kanamycin. All these three compounds were found to possess cytotoxic effect. Minimum inhibitory concentration of these compounds was also determined.

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 Synthesis, spectral studies and in vitro antimicrobial activity of some new di/tri-organotin (IV) complexes of Schiff bases derived from 2-benzoylpyridine

2017 ◽  
Vol 82 (1) ◽  
pp. 13-23 ◽  
Author(s):  
Priyanka Khatkar ◽  
Sonika Asija ◽  
Namita Singh
Keyword(s):  
Schiff Bases ◽  
Antimicrobial Agents ◽  
Lipid Membrane ◽  
Antimicrobial Activities ◽  
Molar Ratio ◽  
Spectral Studies ◽  
Dilution Method ◽  
Gram Positive ◽  
Gram Negative

In the present work, a series of twenty-four organotin (IV) complexes of the type [R2SnLCl, R3SnL] have been synthesized by the condensation of 2-benzoylpyridine Schiff bases with R2SnCl2, R3SnCl (R= Me, n-Bu, Ph) in 1:1 molar ratio. These complexes were well characterized by IR, 1H, and 13C, 119Sn NMR, XRD and mass spectral techniques. In the search for biologically more effective antimicrobial agents, all the synthesized ligands and organotin complexes were evaluated for their in vitro antimicrobial activities against two Gram positive and two Gram negative bacteria, and two fungal strains by serial dilution method. The results of spectral data revealed that the complexes formed were hexacoordinated with tridentate ligands which coordinated through azomethine N, pyridine N and carboxylate O ligation sites. The ligands on co-ordination with tin metal showed a discernible augmentation in biocidal activity, however, the Ph and Bu complexes were found to be more intoxicating. The results revealed that the synthesized complexes were more noxious towards Gram positive strains as compared to Gram negative strains which may be attributed to the presence of an outer lipid membrane of lipopolysaccharides.

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

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.

Synthesis, Characterization, Anti-proliferative Evaluation, and DNA Flow Cytometry Analysis of Some 2-Thiohydantoin Derivatives

2020 ◽  
Vol 20 (18) ◽  
pp. 1929-1941
Author(s):  
Heba A. Elhady ◽  
Hossa F. Al-Shareef
Keyword(s):  
Anticancer Activity ◽  
Schiff Bases ◽  
Anticancer Agents ◽  
Proliferative Activity ◽  
Cancer Cell Line ◽  
Aromatic Aldehydes ◽  
Pharmaceutical Chemistry ◽  
Dna Flow Cytometry ◽  
Quinazoline Derivative ◽  
Reference Drug

Background and Objective: Due to the well-documented anti-proliferative activity of 2-thiohydantoin incorporated with pyrazole, oxadiazole, quinazoline, urea, β-naphthyl carbamate and Schiff bases, they are noteworthy in pharmaceutical chemistry. Methods: An efficient approach for the synthesis of a novel series of 2-thiohydantoin derivatives incorporated with pyrazole and oxadiazole has proceeded via the reaction of the acyl hydrazide with chalcones and/or triethyl orthoformate. Schiff bases were synthesized by the reaction of the acyl hydrazide with different aromatic aldehydes. Moreover, Curtius rearrangement was applied to the acyl azide to obtain the urea derivative, quinazoline derivative, and carbamate derivative. Results: The synthesized compounds structures were discussed and confirmed depending on their spectral data. The anticancer activity of these heterocyclic compounds was evaluated against the breast cancer cell line (MCF-7), where they showed variable activity. Compound 5d found to have a superior anticancer activity, where it has (IC50 = 2.07 ± 0.13 μg/mL) in comparison with the reference drug doxorubicin that has (IC50 = 2.79 ± 0.07 μg / mL). Then compound 5d subjected to further studies such as cell cycle analysis and apoptosis. Apoptosis was confirmed by the upregulation of Bax, downregulation of Bcl-2, and the increase of the caspase 3/7percentage. Conclusion: Insertion of pyrazole, oxadiazole and, quinazoline moieties with 2-thiohydantoin moiety led to the enhancement of its anti-proliferative activity. Hence they can be used as anticancer agents.

Synthesis and Anticancer Activity of New Hydrazide-hydrazones and Their Pd(II) Complexes

2019 ◽  
Vol 16 (5) ◽  
pp. 522-532 ◽  
Author(s):  
Bedia Kocyigit-Kaymakcioglu ◽  
Senem Sinem Yazici ◽  
Fatih Tok ◽  
Miriş Dikmen ◽  
Selin Engür ◽  
...  
Keyword(s):  
Cytotoxic Activity ◽  
Anticancer Activity ◽  
Cell Line ◽  
Cancer Cell ◽  
Cytotoxic Effect ◽  
A549 Cells ◽  
Cancer Cell Line ◽  
Fibroblast Cell ◽  
Reference Drug ◽  
A549 Cancer Cell Line

Background: Hydrazones, one of the important classes of organic molecules, are pharmaceutical agents comprising –CO-NH-N=CH- group in the structure therefore and exhibiting significant biological activity. Methods: 5-Chloro-N’-[(substituted)methylidene] pyrazine-2-carbohydrazide (3a-g) and their Pd(II) complexes (4a-h) were synthesized and investigated in vitro anticancer activity on A549, Caco2 cancer and normal 3T3 fibroblast cell lines, using the MTT assay. Results: Anticancer activity screening results revealed that some compounds showed remarkable cytotoxic effect. Among them, 5-chloro-N'-[(4-hydroxyphenyl)methylidene] pyrazine-2-carbohydrazide (3c) displayed higher cytotoxic activity against A549 cancer cell line than the reference drug cisplatin. Conclusion: Compound 3c showed high cytotoxic activity against A549 cancer cell line but it showed low cytotoxic effect against normal 3T3 fibroblast cell line. Antiproliferative and antimetastatic effects of 3c were determined by the real-time monitoring of cell proliferative system (RTCA DP). The cell proliferation, metastatic and invasive activities of A549 cells were decreased due to increased concentration of 3c.

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