High Antibacterial Potential Research Articles

The Distribution and Antibacterial Activity of Marine Sponge-Associated Bacteria in the Aegean Sea and the Sea of Marmara, Turkey.

The distribution and antibacterial activities of bacteria isolated from fifty-five marine sponge samples collected from the Aegean Sea and the Sea of Marmara were investigated in the period between 2011 and 2013. The antibacterial activities of the methanolic extracts of marine sponge-associated bacteria tested against six pathogenic bacteria: Staphylococcus aureus SA1 and SA2, Brucella melitensis B37, Vibrio vulnificus GK23, Escherichia coli O157:H7 (ATCC 35150), and Salmonella enterica subsp. enterica serovar typhi (ATCC 167), using disk diffusion tests and minimum inhibitory concentration technique. The bacteria isolated from sponges and ambient seawater samples were identified using VITEK 2 Compact 30 automated microbial identification system. All bacterial extracts were exhibited antibacterial activity with various MIC values ranging from 7.8mg/ mL to 1000mg/mL against all pathogenic bacteria tested. The antibacterial efficacy rates found to be higher in the Aegean Sea than the Sea of Marmara samples. Fifty-five sponge samples belonging to fifteen species and host twenty-two bacterial species belonging to seven classes in two different marine areas at varying rates were detected. The most common sponge-associated bacterium was recorded as Sphingomonas paucimobilis and Bacillus cereus in the Aegean Sea and the Sea of Marmara, respectively. The composition and counts of the sponge-associated bacteria were found significantly higher than the free-living bacteria in the ambient sea water sampling points of both two marine areas. The presence of high antibacterial potential of sponge-related bacteria obtained in this study provided data for further studies on marine-derived antimicrobial agents, including the effects of environmental differences.

Synergistic Antibacterial Potentials of Ocimum gratissimum, Honey and Ciprofloxacin against some Multiple Antibiotic-Resistant Bacteria Isolated from Stool Samples

This study investigated the synergistic antibacterial potentials of Ocimum gratissimum (O. gratissimum) leaf acetone extract, honey, and ciprofloxacin against some multiple antibiotic-resistant bacteria. Multiple antibiotic-resistant bacterial isolates from stool samples of diarrhea patients and their typed cultures were subjected to inhibitory assay by mixtures of extract and honey, extract and ciprofloxacin, honey and ciprofloxacin, and extract, honey and ciprofloxacin using tube dilution method. Killing rate and mechanisms of action of the mixtures on the susceptible pathogens were determined. The multiple antibiotic resistance indices of the test organisms (MARI) ranged from 0.7 to 1.0. Extract, honey, and ciprofloxacin mixture at ratio 1:1:1 exerted the lowest minimum inhibitory concentration on E. coli, P. aeruginosa ATCC 10145, E. coli ATCC 25922, and S. typhi ATCC 14028 at 1.56×10-3 mg/mL compared with ciprofloxacin (3.13×10-3 mg/mL). Highest potassium, sodium, and protein leakage was induced by extract and honey mixture (97.4 cmol/g) in E. coli, extract, honey, and ciprofloxacin mixture (65.2 cmol/g) in B. cereus, and extract, honey, and ciprofloxacin mixture (21.6 mg/mL) in B. cereus, respectively. Extract, honey, and ciprofloxacin mixture exerted highest killing rate on B. cereus after 24 h (1.3×101 cfu/mL). These findings revealed a high synergistic antibacterial potential of O. gratissimum leaf acetone extract, honey, and ciprofloxacin against multiple drug-resistant bacteria, thus, implying their potential use in diarrhea treatment.

Effective removal of proteins using carbon‐based nanoadsorbent: relevancy to the application of membrane‐driven pre‐water treatment

AbstractBACKGROUNDProtein is one of the key components of dissolved organic matter (DOM) and poses challenges in water treatment such as membrane fouling. The removal of proteins in preliminary treatment should transform wastewater treatment into a more feasible and cost‐effective process by preventing membrane fouling. In this study, we chemically synthesized nanographene oxide (NGO) and explored its potential as a nanoabsorbent for adsorbing the proteins lysozyme (LYZ) and bovine serum albumin (BSA).RESULTSHere, NGO was synthesized by incorporating some changes in a modified Hummer's method and characterized by various physicochemical methods. We demonstrated the excellent adsorption potential of NGO for the removal of LYZ and BSA from solution. We observed that the adsorption isotherm obeyed the nonlinear Langmuir model; maximal adsorption capacities of 1743.23 and 1156.54 mg g−1 were estimated for LYZ and BSA, respectively. Further, we also demonstrated the excellent regeneration efficiency of NGO whereby removal efficiency dropped by only 5–8% after repeated cycles of adsorption and desorption. Moreover, NGO demonstrated the high antibacterial potential in its protein adsorbed as well as regenerated state against both Gram‐positive and ‐negative bacteria.CONCLUSIONOur findings revealed that carbon‐based NGO might be used as nanoadsorbent for preliminary wastewater treatment before membrane treatment to overcome problems including membrane biofouling, viscosity and foaming that otherwise can cause interference and complications in membrane operation. © 2021 Society of Chemical Industry (SCI).

A Mini Review of Antibacterial Properties of ZnO Nanoparticles

The development of antibiotic resistance of bacteria is one of the most pressing problems in world health care. One of the promising ways to overcome microbial resistance to antibiotics is the use of metal nanoparticles and their oxides. In particular, numerous studies have shown the high antibacterial potential of zinc oxide nanoparticles (ZnO-NP) in relation to gram-positive and gram-negative bacteria. This mini-review includes an analysis of the results of studies in recent years aimed at studying the antibacterial activity of nanoparticles based on zinc oxide. The dependence of the antibacterial effect on the size of the applied nanoparticles in relation to E. coli and S. aureus is given. The influence of various ways of synthesis of zinc oxide nanoparticles and the main types of modifications of NP-ZnO to increase the antibacterial efficiency are also considered.

Characterization and Antibacterial Response of Silver Nanoparticles Biosynthesized Using an Ethanolic Extract of Coccinia indica Leaves

The present study was planned to characterize and analyze the antimicrobial activity of silver nanoparticles (AgNP) biosynthesized using a Coccinia indica leaf (CIL) ethanolic extract. The present study included the preparation of CIL ethanolic extract using the maceration process, which was further used for AgNP biosynthesis by silver nitrate reduction. Biosynthetic AgNPs were characterized using UV–Visible spectrometry, zeta potential analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and energy-dispersive X-ray (EDX) spectrometry. The biogenic AgNP and CIL extracts were further investigated against different bacterial strains for their antimicrobial activity. The surface plasmon resonance (SPR) signal at 425 nm confirmed AgNP formation. The SEM and TEM data revealed the spherical shape of biogenic AgNPs and size in the range of 8 to 48 nm. The EDX results verified the presence of Ag. The AgNPs displayed a zeta potential of −55.46 mV, suggesting mild AgNP stability. Compared to Gram-positive bacteria, the biogenic AgNPs demonstrated high antibacterial potential against Gram-negative bacteria. Based on the results, the current study concluded that AgNPs based on CIL extract have strong antibacterial potential, and it established that AgNP biosynthesis using CIL ethanol extract is an effective process.

Iodine-doped carbon dots with inherent peroxidase catalytic activity for photocatalytic antibacterial and wound disinfection.

A new type of nitrogen-iodine co-doped carbon dot (N/I-CD) was synthesized by a one-step hydrothermal method with a fluorescence quantum yield of 37%. The prepared N/I-CDs exhibit peroxidase-like activity, can catalyze bio-safety levels of H2O2 to generate hydroxyl radicals (•OH) under visible light and enhance the level of reactive oxygen species (ROS) in bacteria cells. All in vitro experiments showed that the designed system has strong photocatalytic antibacterial activity against both E. coli and S. aureus bacteria. The light-induced antibacterial function of N/I-CDs was evaluated under the conditions of changing other experimental parameters. When the visible light irradiation time was extended to 60min, the antibacterial efficiency of N/I-CDs (0.21mg·mL-1) against S. aureus and E. coli reached 100% in the presence of exogenous H2O2 (0.07mM). More importantly, wound disinfection in vivo demonstrates the high antibacterial efficiency, low toxicity and application potential of good biocompatibility due to the nanozyme activity of N/I-CDs.

Antibacterial Activity of Honey from Wild Species of Stingless Bees; <i>Plebenia hylderbrandii</i> and <i>Meliponula bocandei</i>

One of the serious problems the world is facing today is the antimicrobial resistance on available antibiotics by most bacterial pathogens and the rising cost of finding effective antimicrobial agents. In recent years, efforts to find new drugs especially from natural sources have been boosted by the demand for an effective cure for infectious diseases. Only the antibacterial activity of apis mellifera honey and not stingless bee honey from western Kenya has been reported. This study was therefore carried out to determine the effect of Plebenia hylderbrandii and Meliponula bocandei honey samples on the growth of control; sensitive cases of Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923). Different honey concentrations (1.18% - 17.65% v/v) of the two samples were tested against the two micro-organisms. The samples were screened for their antibacterial potential against Escherichia coli and Staphylococcus aureus by agar well dilution method. The Partial inhibitory concentration (PIC), minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were determined by in vitro method. The inhibitory effect of Plebenia hylderbrandii honey on E. coli and S. aureus growth was apparent at concentrations 3.53% and 1.76% (v/v) respectively. On the other hand, the inhibitory effect of Meliponula bocandei honey on S. aureus growth was at concentration 16.47% (v/v). Plebenia hylderbrandii honey had bactericidal effect on both E. coli and S. aureus at concentrations 4.71% and 2.35% (v/v) respectively. However, Meliponula bocandei honey exerted bactericidal effect on S. aureus only at 16.47% (v/v) concentration. Plebenia hylderbrandii honey had higher antibacterial potency and can be a potential source of antibacterial substances. Moreover, the honeys tested in this study showed great antibacterial potential for S. aureus.

Synthesis and Bioactivity of Guanidinium-Functionalized Pillar[5]arene as a Biofilm Disruptor.

Due to the inherent resistance of bacterial biofilms to antibiotics and their serious threat to global public health, novel therapeutic agents and strategies to tackle biofilms are urgently needed. To this end, we designed and synthesized a novel guanidinium-functionalized pillar[5]arene (GP5) that exhibited high antibacterial potency against Gram-negative E. coli (BH101) and Gram-positive S. aureus (ATCC25904) strains. More importantly, GP5 effectively disrupted preformed E. coli biofilms by efficient penetration through biofilm barriers and subsequent destruction of biofilm-enclosed bacteria. Furthermore, host-guest complexation between GP5 and cefazolin sodium, a conventional antibiotic that otherwise shows negligible activity against biofilms, exhibited much enhanced, synergistic disruption activity against E. coli biofilms, thus providing a novel supramolecular platform to effectively disrupt biofilms.

Synthesis and Bioactivity of Guanidinium‐Functionalized Pillar[5]arene as a Biofilm Disruptor

AbstractDue to the inherent resistance of bacterial biofilms to antibiotics and their serious threat to global public health, novel therapeutic agents and strategies to tackle biofilms are urgently needed. To this end, we designed and synthesized a novel guanidinium‐functionalized pillar[5]arene (GP5) that exhibited high antibacterial potency against Gram‐negative E. coli (BH101) and Gram‐positive S. aureus (ATCC25904) strains. More importantly, GP5 effectively disrupted preformed E. coli biofilms by efficient penetration through biofilm barriers and subsequent destruction of biofilm‐enclosed bacteria. Furthermore, host–guest complexation between GP5 and cefazolin sodium, a conventional antibiotic that otherwise shows negligible activity against biofilms, exhibited much enhanced, synergistic disruption activity against E. coli biofilms, thus providing a novel supramolecular platform to effectively disrupt biofilms.

Efficacy of Plasma ONE apparatus for disinfection of S. aureus, P. aeruginosa and E. coli bacteria from the solid surface

Cold atmospheric plasma (CAP) is a cocktail of charged particles with high antibacterial potency. In this study, we evaluated CAP efficacy generated by Plasma ONE, a mobile medical device against common chronic wound pathogens. Two sets of working saline suspensions, i.e. 105 and 103 CFU/ml of each reference strain E. coli, P. aeruginosa and S. aureus, were inoculated on Mueller–Hinton media plates and exposed to CAP for 30, 60, 120, 300 s and incubated for 24 h. The radiating nozzle surface was 3.4 cm. Plasma efficacy evaluation was based on the diameter of attained inactivation area and bacterial decontamination rate within. Plasma ONE device showed high capacity against S. aureus in all time intervals and exposure yielded a gradual time-dependent CFU reduction starting with 99.6% after 30 s in the 105 plates. Comparison between mean area diameters of S. aureus and E. coli of 30 and 120 s indicated a significant area increase (p < 0.05). In contrast, P. aeruginosa appeared more resistant to a longer exposure and the inactivation area was hardly extended following the longest exposure. In both Gram-negative bacteria, CFU reduction plateaued at 30 s in 103 petri dishes, while in 105 groups more than 120-s interval was insufficient for attaining full decontamination; however, treatment for 300 s led to complete eradication. Plasma ONE is effective against most commonly isolated pathogens from wounds, but its further validation requires data concerning efficacy in eradicating biofilms.

Synergistic Nanocomposites of Different Antibiotics Coupled with Green Synthesized Chitosan-Based Silver Nanoparticles: Characterization, Antibacterial, in vivo Toxicological and Biodistribution Studies.

PurposeThe present study reports chitosan functionalized green synthesized CS-AgNPs, conjugated with amoxicillin (AMX), cefixime (CEF), and levofloxacin (LVX) for safe and enhanced antibacterial activity.MethodsThe CS-AgNPs and conjugates CS-AgNPs+AMX CS-AgNPs+CEF, and CS-AgNPs+LVX were characterized by UV–Vis, FTIR, SEM, TEM, EDX spectroscopy. The size distribution and zeta potential were measured using the dynamic light scattering (DLS) technique. The interaction between CS-AgNPs and antibiotic molecules was also investigated using UV–Vis spectroscopy at the concentrations of 5, 50, 500, and 5000 µM for each antibiotic. Antibacterial activity and synergism were assessed by the Fractional Inhibitory Concentration (FIC) index. The mechanism for synergistic activity was investigated by the detection of hydroxyl species based on the chemiluminescence of luminol. The biocompatibility index (BI) was calculated from IC50 using the HeLa cell line. In vivo toxicity and tissue distribution of silver ions were evaluated on Sprague Dawley rats. Physical interactions of antibiotics and significant (P<0.05) antibacterial activity were observed after loading on CS-AgNPs surfaces.ResultsThe spherical shape nanocomposites of CS-AgNPs with different antibiotics were prepared with mean size ranges of 80–120 nm. IC50 of antibiotics-conjugated CS-AgNPs decreased compared to CS-AgNPs. The biocompatibility (BI) index showed that antibiotics-conjugated CS-AgNPs have high antibacterial potential and low toxicity. Highly significant (P<0.005) increase in the generation of hydroxyl species indicated the radical scavenging mechanism for synergistic activity of CS-AgNPs after combined with different antibiotics. Biochemical analysis and histopathological examinations confirmed low toxicity with minor hepatotoxicity at higher doses. After oral administration, extensive distribution of Ag ion was observed in spleen and liver.ConclusionThe study demonstrates positive attributes of antibiotics-conjugated CS-AgNPs, as a promising antibacterial agent with low toxicity.

MeJA Elicitation of Chicory Hairy Roots Promotes Efficient Increase of 3,5-diCQA Accumulation, a Potent Antioxidant and Antibacterial Molecule.

Cichorium intybus L. (Asteraceae) is an important industrial crop, as well as a medicinal plant which produces some bioactive compounds implicated in various biological effects with potential applications in human health. Particularly, roots produce hydroxycinnamic acids like 5-caffeoyquinic acid and 3,5-dicaffeoylquinic acid (di-CQA). The present investigation relates to the use of methyl jasmonate for enhancing phenolic compounds accumulation and production in hairy root cultures of C. intybus. Elicitated hairy root growth rate increased 13.3 times compared with the initial inoculum in a period of 14 days and di-CQA production represented about 12% of DW. The elicitation has also promoted the production of tricaffeoylquinic acid never described in the chicory roots and identified as 3,4,5-tricaffeoyquinic acid by means of nuclear magnetic resonance. Our study confirmed the strong anti-oxidant effect of di-CQA. Our results also confirmed globally a selectivity of action of di-CQA against Gram-positive bacteria, in particular against some strains of Staphylococcus and Streptococcus. However, a non-negligible antibacterial activity of di-CQA against Pseudomonas aeruginosa was also underlined (MIC = 0.156 mg.mL−1 against some P. aeruginosa strains). The influence of di-CQA has been explored to evaluate its impact on the physiology of P. aeruginosa. Di-CQA showed no effect on the biofilm formation and the production of extracellular pyocyanin. However, it demonstrated an effect on virulence through the production of pyoverdine with a dose-dependent manner by more than 7-fold when treated at a concentration of 128 µg·mL−1, thus suggesting a link between di-CQA and iron sequestration. This study shows that elicitated hairy root cultures of chicory can be developed for the production of di-CQA, a secondary metabolite with high antibacterial potential.

Antimycobacterial activity of azepanobetulin and its derivative: In vitro, in vivo, ADMET and docking studies

The antimycobacterial investigation of azepanobetulin and its amide derivative was performed. Both compounds showed increased in vitro antibacterial activity on the H37Rv MTB strain in aerobic and anaerobic conditions. Basing on differences between MIC and IC50 values a predominant bactericidal effect for amide in contrast to azepanobetulin with a bacteriostatic antibacterial mechanism is defined. Both compounds showed a strong antibacterial effect against resistant MTB strains with amide derivative being slightly more active. Amide derivative also showed a higher antibacterial potency against non-tuberculous mycobacterial strains (M. avium, M. abscessus). Molecular docking studies showed that the inhibition of tuberculosinyl adenosine transferase (Rv3378c) could constitute an antimycobacterial mechanism of action for these triterpenic azepane derivatives. The pharmacokinetic profile was evaluated by ADMET studies and azepanobetulin showing the better results was evaluated by in vivo experiments. This compound has demonstrated a statistically significant antimycobacterial activity compared to control, but inferior to isoniazid. Our findings show that pentacyclic triterpene derivatives holding a seven-membered azepane A-ring are the promising template for the development of new agents with high antibacterial potential against M. tuberculosis H37Rv, non-tuberculous mycobacterial and drug- resistant strains.

Phytochemical screening of bunga rosella (Hibiscus sabdariffa L) and antimicrobial activity test

The purpose of this study was to determine the antimicrobial activity of rosella infusa ( Hibiscus sabdariffa L.). Antimicrobial inhibition test using infusa of rosella ( Hibiscus sabdariffa L.) against Staphylococcus aureus and Escherichia coli bacteria at a concentration of infusa 100%; 75%; and 50%. The concentration has highest potential antibacterial of infusa for Staphylococcus aureus is 100% witch has diameter of 13.6 mm and for Escherichia coli bacteria is 100%, its show that diameter of zone inhibitory zone is 13.3 mm. The Results of phytochemical screening show that infusa of rosella ( Hibiscus sabdariffa L.) contains flavonoids, saponins, and tannins. Based on the data above show that the infusa of rosella flower has high antibacterial potential. Keywords: Hibiscus sabdariffa L., antimicrobial activity , Staphylococcus aureus, Escherichia coli

Ecofriendly Green Synthesis of Iron Oxide Nanoparticles Using citrus sinensis

Green protocols being eco-friendly and cost effective approach are most widely used for the production of iron oxide nanoparticles using plant-mediated extract of Citrus Sinensis, moreoverbiosynthesized iron oxide (FeO) nanoparticles shows better antibacterial activity.Green synthesis of nanoparticles has been broadly studied from the past few years because of their different features and potential applications in various fields. The successful biosynthesis of iron oxide nanoparticles was confirmed and characterized using UV-Visible spectroscopy, Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR) analysis and Zeta sizer. Antibacterial effect of biologically produced iron oxide nanoparticles was tested against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Macrococus). These results exhibited that iron oxide nanoparticles have high antibacterial potential as these nanoparticles showed significant zone of inhibition against bacteria strains. The proposed green synthesis of iron oxide nanoparticles (NPs) from Citrus Sinensis can be strongly recommended as a potential method for industrial application.

Synthesis, antibacterial evaluation, in silico ADMET and molecular docking studies of new N-acylhydrazone derivatives from acridone

Novel N-acylhydrazone derivatives from acridone have been synthesized by condensation of acridone acetohydrazide and various aldehyde. The novel acylhydrazones were tested for their in-vitro antibacterial activity against human pathogenic strains. The MIC results indicate that compound 3f displayed high antibacterial potential against Pseudomonas putida with MIC = 38.46 µg/mL, which is very close to that obtained with the commercial antibiotic. The synthesized compounds were subjected for docking studies to understand the interaction of our compounds and transcriptional regulator enzyme of pseudomonas putida and DNA gyrase complex of Staphyloccocus aureus.

Dental Materials Incorporated with Nanometals and Their Effect on the Bacterial Growth of Staphylococcus aureus.

PurposeThe purpose of this study was to investigate the effect of different commercially used dental materials (RelyX Luting Plus and Dyract Extra) mixed with either a metallic ionic solution or a colloidal suspension of metallic nanoparticles. Both the solution and the suspension contained a mixture of silver, copper, and lithium ions.MethodsThe metal/ion-incorporated dental materials were prepared into disk-shaped samples and tested against the growth of Staphylococcus aureus. The susceptibility of bacteria against the antibacterial dental disks was tested using two methods: counting the colony-forming units per milliliter and disk diffusion (Kirby–Bauer). The incorporated materials (Dyract and Rely cement) were tested for ion release using flame atomic absorption spectroscopy.ResultsAssessment showed efficient antibacterial activity of metal ion–incorporated Rely luting cement, exhibited by the formation of inhibition zones larger than those formed by the standard antibiotic, as well as a reduction in bacterial number of sevenfold after incubation for 24 hours. Dyract material incorporated with nanoparticles showed no significant clear zones and had no inhibiting effect on bacterial colony numbers after incubation for 24 hours. The release of silver, copper, and lithium metal ions depended on the type of both dental material and the incorporated nanoagents. The metal ion–incorporated Rely Plus cement released the highest levels of metal ions, which was attributed to its antibacterial efficiency.ConclusionRely Plus cement incorporated with the nanoparticle suspension demonstrated high antibacterial potency, due to the release of the highest concentrations of silver, copper, and lithium metal ions. This work is the first direct comparative study of dental materials with different forms of nanomixtures (metallic nanoparticles and soluble metallic ions) and their antibacterial effects after incubation with bacterial culture for 24 hours.

Antibacterial Effects of Newbouldia laevis {P. BEAUV} on the Bacteria Isolated from the Blood of Hepatitis C Virus Positive Individuals

The methanol, chloroform and aqueous leaf extracts of Newbouldia laevis Were obtained using cold extraction method. Phytochemical screening {qualitative} of the extracts was investigated and the inhibitory activity of extracts against the isolates were assayed by agar well diffusion technique. The concentrations were varied from 100 mg/ml to 400 mg/ml and zones of inhibition at every concentration were recorded. The bacterial isolates including Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Streptococcus pnuemoniae and Salmonella sp. The extracts revealed the presence of flavonoids, tannins, terpenes, alkanoids, phenolics, saponins and cardiac glycosides with exception of chloroform extract that revealed the presence of alkanoids, saponins and tannins only. Antibacterial activity revealed that methanol extract had the highest potency with 23.03±0.33e mm, followed by aqueous extract with 21.75±0.22d mm zones of inhibition against S. aureus, and the chloroform extract had the highest activity of 16.0±0.59d mm zone of inhibition against Salmonella sp. while aqueous extract had the least zone of inhibition against P. mirabilis with 10.07±0.67a mm on isolates. All the extracts, irrespective of the extracting solvents had a minimum inhibitory concentrations {MIC} range of 6.25 – 50 mg/ml and minimum bactericidal concentrations {MBC} range of 12.5 – 100 mg/ml. Findings from this research shows that N. laevis has high antibacterial potency against pathogens in blood even in comparison with some conventional antibiotics used.

Study of the Antibacterial Activity of Elettaria Cardamomum Extracts on the Growth of Some Gingivitis Inducing Bacteria in Culture Media

The our work was carried out with an objective to appraisal the antibacterial action of cardamom extracted by four different solvents and prepared in a number of concentrations (50, 100 and 200 mg/mL) toward three different pathogenic bacteria responsible mainly for induce gingivitis infection and comparison their action with the action of antibiotics (Ciprofloxacin (5μg), Ampicillin (30μg) in culture media. The results of phytochemical profiles for different extracts of cardamom showed the presence of alkaloids, glycosides, tannins, and terpenes in all used extracts while flavonoids were present in all extracts except watery extract. Saponins were present only in the ethanolic extract, while phenols were found to be present only in ethanolic and chloroformic extracts. The antibacterial screening of the different extracts of cardamom and standard antibiotics showed various degrees of zones of inhibition in the culture media depending largely upon the type of plant extract, the concentration of extract in addition to the type of tested bacterial. Almost all the cardamom extracts were found to have significant activity (p less than 0.05) against all tested bacteria com the pared with a negative control. The highest antibacterial potential was observed for the ethanolic cardamom extract, whereas other cardamom extracts showed closed results in general. At the same time, the current study was recorded that inhibition zones diameter against tested bacteria raised significantly (p less than 0.05) as the extract concentration raised. The MIC values of watery, ethanolic, chloroformic, and acetonic extracts of cardamom ranged from 0.624 to 1.248 mg/mL, 0.078 to 0.312mg/mL, 0.624 to 1.248 and 0.312 to 0.624 mg/mL against tested bacteria respectively. While the MBC values ranged from 1.248 to 10 mg/mL, 0.624 to 2.5 mg/mL, 2.5mg/mL to 5 mg/mL and 2.5mg/mL respectively.

Synthetic and Biological Studies on New Urea and Triazole Containing Cystobactamid Derivatives.

Cystobactamids belong to the group of arene‐based oligoamides that effectively inhibit bacterial type IIa topoisomerases. Cystobactamid 861‐2 is the most active member of these antibiotics. Most amide bonds present in the cystobactamids link benzoic acids with anilines and it was found that some of these amide bonds undergo chemical and enzymatic hydrolysis, especially the one linking ring C with ring D. This work reports on the chemical synthesis and biological evaluation of thirteen new cystobactamids that still contain the methoxyaspartate hinge. However, we exchanged selected amide bonds either by the urea or the triazole groups and modified ring A in the latter case. While hydrolytic stability could be improved with these structural substitutes, the high antibacterial potency of cystobactamid 861‐2 could only be preserved in selected cases. This includes derivatives, in which the urea group is positioned between rings A and B and where the triazole is found between rings C and D.