Antibacterial Activity and Irritation Potential of Selected Essential Oil Components – Structure-Activity Relationship

A selection of structurally diverse components of essential oils was subjected to an antibacterial screening against the Gram-positive bacteria Staphylococcus aureus and Streptococcus pneumoniae as well as the Gram-negative bacteria Escherichia coli and Haemophilus influenzae using a broth microdilution method. In addition, the irritation potential of these substances to mucous membranes was evaluated by a modified HET-CAM (Hen's Egg Test-Chorioallantoic Membrane) assay. Minimum inhibitory concentrations (MIC) and irritation threshold concentrations (ITC) were compared in order to identify substances with a low mucous membrane irritation potential at the antibacterially effective concentration. Regarding the antibacterial activity, the most active substances were cinnamaldehyde, phenols, monoterpene alcohols and aldehydes. Oxygenated monoterpenes and phenylpropanoids without either alcohol or aldehyde function (ethers, ketones) showed moderate activity. Mono- and sesquiterpene hydrocarbons, as well as sesquiterpene alcohols, were more or less inactive against most of the bacteria tested, with the exception of Streptococcus pneumoniae whose growth was inhibited by sesquiterpenes at exceptionally low concentrations. In most cases, the irritation potential of the test compounds could also be traced back to their structural features. 2-Phenylethanol, monoterpene alcohols, phenols and aromatic aldehydes had the lowest ITC-values, followed by monoterpene aldehydes, ketones and ethers. In contrast, monoterpene hydrocarbons caused irritation only at higher doses. Of special interest was the fact that all the sesquiterpenes tested were not irritant even when applied undiluted to the chorioallantoic membrane (CAM).

Download Full-text

Synthesis andIn VitroEvaluation of New Thiosemicarbazone Derivatives as Potential Antimicrobial Agents

Journal of Chemistry ◽

10.1155/2016/1692540 ◽

2016 ◽

Vol 2016 ◽

pp. 1-7 ◽

Cited By ~ 6

Author(s):

Zafer Asım Kaplancıklı ◽

Mehlika Dilek Altıntop ◽

Belgin Sever ◽

Zerrin Cantürk ◽

Ahmet Özdemir

Keyword(s):

Antibacterial Activity ◽

Pathogenic Bacteria ◽

Antimicrobial Agents ◽

Aromatic Aldehydes ◽

Antitubercular Activity ◽

Alamar Blue Assay ◽

Alamar Blue ◽

Inhibitory Effects ◽

Microdilution Method ◽

Broth Microdilution Method

In an effort to develop potent antimicrobial agents, new thiosemicarbazone derivatives were synthesizedviathe reaction of 4-[4-(trifluoromethyl)phenyl]thiosemicarbazide with aromatic aldehydes. The compounds were evaluated for their inhibitory effects on pathogenic bacteria and yeasts using the CLSI broth microdilution method. Microplate Alamar Blue Assay was also carried out to determine the antimycobacterial activities of the compounds againstMycobacterium tuberculosisH37Rv. Among these derivatives, compounds5and11were more effective againstEnterococcus faecalis(ATCC 29212) than chloramphenicol, whereas compounds1,2, and12and chloramphenicol showed the same level of antibacterial activity againstE. faecalis. Moreover, compound2and chloramphenicol exhibited the same level of antibacterial activity againstStaphylococcus aureus. On the other hand, the most potent anticandidal derivatives were found as compounds2and5. These derivatives and ketoconazole exhibited the same level of antifungal activity againstCandida glabrata. According to the Microplate Alamar Blue Assay, the tested compounds showed weak to moderate antitubercular activity.

Download Full-text

Microwave assisted synthesis of novel Pyrazole derivatives and their biological evaluation as anti-bacterial agents

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207323666201019152206 ◽

2020 ◽

Vol 23 ◽

Author(s):

Hadis Khodadad ◽

Farhad Hatamjafari ◽

Khalil Pourshamsian ◽

Babak Sadeghi

Keyword(s):

Antibacterial Activity ◽

Aromatic Aldehydes ◽

Catalytic Amount ◽

Antibacterial Activities ◽

Structural Features ◽

Biological Evaluation ◽

Aureus Strain ◽

Microwave Assisted Synthesis ◽

Pyrazole Derivatives ◽

Microwave Assisted

Aim and Objective: Microwave-assisted condensation of acetophenone 1 and aromatic aldehydes 2 gave chalcone analogs 3, which were cyclized to pyrazole derivatives 6a-f via the reaction with hydrazine hydrate and oxalic acid in the presence of the catalytic amount of acetic acid in ethanol. Materials and Methods: The structural features of the synthesized compounds were characterized by melting point, FT-IR, 1H, 13C NMR and elemental analysis. Results: The antibacterial activities of the synthesized pyrazoles was evaluated against three gram-positive bacteria such as Enterococcus durans, Staphylococcus aureus, Bacillus subtilis and two gram-negative bacteria such as Escherichia coli and Salmonella typhimurium. Conclusion: All the synthesized pyrazoles showed relatively high antibacterial activity against S. aureus strain and none of them demonstrated antibacterial activity against E. coli.

Download Full-text

Synthesis and Antibacterial Activities of Amidine Substituted Monocyclic β-Lactams

Medicinal Chemistry ◽

10.2174/1573406417666210830122954 ◽

2021 ◽

Vol 17 ◽

Author(s):

Lijuan Zhai ◽

Lili He ◽

Yuanbai Liu ◽

Ko Ko Myo ◽

Zafar Iqbal ◽

...

Keyword(s):

Antibacterial Activity ◽

Bacterial Species ◽

Antimicrobial Effect ◽

Antibacterial Activities ◽

Lead Target ◽

Bacterial Strains ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Clinical Interest

Background: Mononcyclic β-lactams are regarded as the most resistant class of β-lactams against a series of β-lactamases though possess limited antibacterial activity. Aztreonam being the first clinically approved monobactam needs broad-spectrum efficacy through structural modification. Objective: We strive to synthesize a number of monocyclic β-lactams by varying the substituents at N1, C3 and C4 positions of azetidinone ring and study the antimicrobial effect on variable bacterial strains. Methods: Seven new monobactam derivatives 23a-g, containing substituted-amidine moieties linked to the azetidinone ring via thiazole linker, were synthesized through multistep synthesis. The final compounds were investigated for their in vitro antibacterial activities using broth microdilution method, against ten bacterial strains of clinical interest. The minimum inhibitory concentrations (MICs) of newly synthesized derivatives were compared with aztreonam, ceftazidime and meropenem, existing clinical antibiotics. Results: All compounds 23a-g showed higher antibacterial activities (MIC 0.25 µg/mL to 64 µg/mL) against tested strains as compared to aztreonam (MIC 16 µg/mL to >64 µg/mL) and ceftazidime (MIC >64 µg/mL). However all compounds, except 23d, exhibited lower antibacterial activity against all tested bacterial strains as compared to meropenem. Conclusion: Compound 23d showed comparable or improved antibacterial activity (MIC 0.25 µg/mL to 2 µg/mL) to meropenem (MIC 1 µg/mL to 2 µg/mL) in case of seven bacterial species. Therefore, compound 23d may be valuable lead target for further investigations against multi-drug resistant Gram-negative bacteria.

Download Full-text

Variation in erythromycin and clindamycin susceptibilities of Streptococcus pneumoniae by four test methods.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.41.1.129 ◽

1997 ◽

Vol 41 (1) ◽

pp. 129-134 ◽

Cited By ~ 39

Author(s):

E L Fasola ◽

S Bajaksouzian ◽

P C Appelbaum ◽

M R Jacobs

Keyword(s):

Streptococcus Pneumoniae ◽

Susceptibility Testing ◽

Ambient Air ◽

Test Methods ◽

Disk Diffusion ◽

Broth Microdilution ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Agar Dilution ◽

Resistant Strains

Susceptibilities of 124 strains of Streptococcus pneumoniae to erythromycin and clindamycin were determined by the National Committee for the Clinical Laboratory Standards (NCCLS) broth microdilution method, with incubation for 20 to 24 h in ambient air and with modifications of this method by incubation for up to 48 h in air and CO2. Strains were also tested by agar dilution, E-test, and disk diffusion; good correlation was obtained with these methods, with clear separation into bimodal populations of susceptible and resistant stains. The broth microdilution method, however, using incubation in air for 24 h (NCCLS method), misclassified 4 of 92 erythromycin-resistant strains (1 as susceptible and 3 as intermediate) and 25 of 58 clindamycin-resistant strains (all as susceptible). With the exception of one strain with clindamycin, susceptible and resistant strains were correctly classified by the microdilution method with incubation in CO2 for 24 h or in ambient air for 48 h. Disk diffusion, agar dilution, and E-test methods with incubation in 5% CO2 are therefore reliable methods for susceptibility testing of pneumococci against these agents. However, the NCCLS microdilution method, which specifies incubation for 20 to 24 h in ambient air, produced significant very major errors (43%) clindamycin. Modification of the microdilution method by incubation in 5% CO2 or by extension of incubation time in ambient air to 48 h corrected these errors. Disk diffusion, however, was shown to be a simple, convenient, and reliable method for susceptibility testing of pneumococci to erythromycin and clindamycin and is suggested as the method of choice for these agents.

Download Full-text

Antibacterial Triterpenoids from the Bark of Sonneratia alba (Lythraceae)

Natural Product Communications ◽

10.1177/1934578x1501000215 ◽

2015 ◽

Vol 10 (2) ◽

pp. 1934578X1501000

Author(s):

Harizon ◽

Betry Pujiastuti ◽

Dikdik Kurnia ◽

Dadan Sumiarsa ◽

Yoshihito Shiono ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Antibacterial Activity ◽

Mass Spectrometric ◽

Broth Microdilution ◽

Mass Spectrometric Data ◽

Spectrometric Data ◽

Gram Positive Bacteria ◽

Microdilution Method ◽

Sonneratia Alba ◽

Broth Microdilution Method

The new lupane-type triterpenoid, 3β-hydroxy-lup-9(11), 12-diene, 28-oic acid (1), along with two known lupane-type triterpenoids, lupeol (2) and lupan-3p-ol (3), were isolated from the bark of Sonnetaria alba. The structure of the new compound was elucidated on the basis of spectroscopic and mass spectrometric data analysis. Using the broth microdilution method, all compounds exhibited antibacterial activity against the Gram-positive bacteria Staphylococcus aureus ATCC 6538 and Streptococcus mutans ATCC 25175, with minimum inhibitory concentrations ranging from 15-33 to 35-55 ng/mL, respectively.

Download Full-text

Antibacterial Activity of the Essential Oil of Heracleum Sibiricum

Natural Product Communications ◽

10.1177/1934578x1300800931 ◽

2013 ◽

Vol 8 (9) ◽

pp. 1934578X1300800 ◽

Cited By ~ 4

Author(s):

Dragoljub L. Miladinović ◽

Budimir S. Ilić ◽

Tatjana M. Mihajilov-Krstev ◽

Dejan M. Nikolić ◽

Olga G. Cvetković ◽

...

Keyword(s):

Antibacterial Activity ◽

Essential Oil ◽

Antimicrobial Activities ◽

Bacterial Strains ◽

Gram Positive Bacteria ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Major Chemical ◽

Total Oil ◽

Chemical Class

The composition and antimicrobial activity of the essential oil of Heracleum sibiricum L. (Apiaceae) was studied. The aerial part of plant was hydro-distilled and chemical composition of the essential oil was analyzed by GC and GC-MS. Forty-six compounds, corresponding to 95.12% of the total oil, were identified. Esters represented the major chemical class (69.55%) while the main constituents were octyl butanoate (36.82%), hexyl butanoate (16.08%), 1-octanol (13.62%) and octyl hexanoate (8.10%). Antibacterial activity of the essential oil and reference antibiotics against nine bacterial strains was tested by the broth microdilution method. The results of the bioassays showed that essential oil had slight antimicrobial activities against all tested microorganisms (MIC and MBC values were in the range of 2431.2 to 9724.8 μg/mL). Reference antibiotics were active in concentrations between 0.5 and 16.0 μg/mL. The results confirm that Gram-positive bacteria were more susceptible to the essential oil of H. sibiricum, in comparison with Gram-negative bacteria.

Download Full-text

Antibacterial Activity of Antibiotic-Impregnated Bone Cement Based Coatings Against Microorganisms with Different Antibiotic Resistance Levels

Traumatology and Orthopedics of Russia ◽

10.21823/2311-2905-2018-24-4-105-110 ◽

2018 ◽

Vol 24 (4) ◽

pp. 105-110

Author(s):

D. V. Tapalski ◽

P. A. Volotovski ◽

A. I. Kozlova ◽

A. Sitnik

Keyword(s):

Antibacterial Activity ◽

Bone Cement ◽

Antibiotic Activity ◽

Broth Microdilution ◽

Antibiotic Resistant ◽

Microdilution Method ◽

Bactericidal Properties ◽

Broth Microdilution Method ◽

Marked Activity ◽

Agar Method

Purpose — to evaluate the presence and duration of antibiotic activity of antibiotic-impregnated bone cement based coatings samples against antibiotic-sensitive and antibiotic-resistant microorganisms.Material and Methods. Bone cement based coatings impregnated with antibiotics (gentamycin, vancomycin, colistin, meropenem, fosfomycin) are formed on titanium (Ti) plates. A plate rinse was carried out; antibiotic concentrations in the rinsed solutions were estimated by a serial broth microdilution method. Antibacterial activity of the control and rinsed samples against the antibiotic-sensitive and multiple-antibiotic-resistant Staphylococcus aureus and Pseudomonas aeruginosa strains was estimated by a bilayer agar method.Results. The meropenem and fosfomycin concentrations in the rinsed solutions obtained at a one-fold (16 μg/ml for both antibiotics) and two-fold treatment (2 μg/ml for meropenem and 8 μg/ml for fosfomycin) were sufficient to suppress the growth of the control strains. One-fold rinse of samples with colistin eliminated their antibacterial activity completely. The marked activity of the samples with meropenem and fosfomycin persisted against the antibiotic-sensitive P. aeruginosa ATCC 27853 strain after 2 rinse cycles; single-rinsed samples with fosfomycin also maintained the activity against the extensively antibioticresistant P. aeruginosa BP-150 strain. Vancomycin-containing samples possessed the sufficient antibacterial activity against both methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) S. aureus strains; two-fold rinse of the samples eliminated their bactericidal properties.Conclusion. Bone cement based coatings impregnated with fosfomycin and meropenem possess the most marked and long-lasting antibacterial activity, manifested mainly against the antibiotic-sensitive strains.

Download Full-text

Semi-bionic Extraction Process and Antibacterial Activity against Salmonella goose of Compound Chinese Medicine Dahuang Qinyu San

International Journal of Pharmaceutical Sciences Review and Research ◽

10.47583/ijpsrr.2021.v71i02.016 ◽

2021 ◽

Vol 71 (2) ◽

Author(s):

Hatungimana Françoise ◽

Hongjun Wang

Keyword(s):

Antibacterial Activity ◽

Ph Value ◽

Design Method ◽

Uniform Design ◽

Extraction Process ◽

Chinese Herbs ◽

Optimal Conditions ◽

Liquid Ratio ◽

Microdilution Method ◽

Broth Microdilution Method

Various classical Chinese medicines have shown their efficiency in curing various infectious diseases. Among them, Dahuang Qinyu San (DQS) found in the Chinese Veterinary Pharmacopoeia is composed of three kinds of Chinese herbs: rhubarb, Scutellaria baicalensis, and Outtuynia cordata. Due to its urgent need in human health and its effectiveness, a semi-bionic extract of Dahuang Qinyu San (SEDQS) was studied to evaluate its optimal extraction conditions and investigate its antibacterial activity against Salmonella goose. The U5 (53) uniform design method was used to investigate the effects of three independent variables, including pH value (X1), solid-to-liquid ratio (X2), and extraction time (X3), on the composite score (Y) of the extract rate and the MIC, using the semi-bionic extraction process. The broth microdilution method was also used to determine the minimum inhibitory concentration (MIC) against Salmonella goose. After 30 minutes of extraction, the optimal conditions for SEDQS were found to be pH 8.3 and a solidto-liquid ratio of 1: 40. Under these optimal conditions, the extraction rate was 43.66 % and the MIC was 9.10 mg/ml, which indicates antibacterial efficacy against Salmonella goose.

Download Full-text

Identification of Substances Produced by Cercospora brachiata in Absence of Light and Evaluation of Antibacterial Activity

Journal of Fungi ◽

10.3390/jof7090680 ◽

2021 ◽

Vol 7 (9) ◽

pp. 680

Author(s):

John K. R. P. Felisbino ◽

Bruno S. Vieira ◽

Alberto de Oliveira ◽

Neiliane A. da Silva ◽

Carlos H. G. Martins ◽

...

Keyword(s):

Mass Spectrometry ◽

Fatty Acids ◽

Antibacterial Activity ◽

Ethyl Acetate Extract ◽

Phytopathogenic Fungus ◽

Broth Microdilution ◽

Actinomyces Naeslundii ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Almost All

Cercospora brachiata is a phytopathogenic fungus. To know more about the metabolites produced by this fungus, the objective of this work was to identify, isolate and characterize substances present in extracts of the growth broth and mycelium, using gas chromatography with mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). It was also objective to evaluate the antibacterial activity of the extracts. Among the compounds identified, fatty acids, esters, and steroids can be highlighted. The main compounds identified are 9-hexadecenoic, hexadecenoic, oleic, octadecanoic, lauric, myristic, palmitic, doceno-13-enoic, stearic, linoleic, and nonadecanoic acids present in almost all extracts. For the antibacterial activity, the broth microdilution method was used. The ethyl acetate extract of the mycelium presented inhibitory concentrations (MICs) against the bacterium Actinomyces naeslundii (100 μg mL−1) and Streptococcus sanguinis (200 μg mL−1). Finally, two steroids were isolated and identified in the hexane extract of mycelium: ergosta-6,22-dien-3β,5α,8α-triol and brassicasterol.

Download Full-text

In vitro Antibacterial Activity of Libanotis montana Essential Oil in Combination with Conventional Antibiotics

Natural Product Communications ◽

10.1177/1934578x1400900238 ◽

2014 ◽

Vol 9 (2) ◽

pp. 1934578X1400900 ◽

Cited By ~ 4

Author(s):

Dragoljub L. Miladinović ◽

Budimir S. Ilić ◽

Tatjana M. Mihajilov-Krstev ◽

Jovana L. Jović ◽

Marija S. Marković

Keyword(s):

Gas Chromatography ◽

Antibacterial Activity ◽

Chemical Composition ◽

Essential Oil ◽

Hierarchical Cluster ◽

Gas Chromatography Mass Spectrometry ◽

Bacterial Strains ◽

Microdilution Method ◽

Broth Microdilution Method

The chemical composition and antibacterial activity were examined of Libanotis montana Crantz subsp. leiocarpa (Heuff.) Soó. (Apiaceae) essential oil. Gas chromatography and gas chromatography/mass spectrometry were used to analyze the chemical composition of the oil. The antibacterial activity was investigated by the broth microdilution method against thirteen bacterial strains. The interactions of the essential oil and three standard antibiotics: tetracycline, streptomycin and chloramphenicol toward five selected strains were evaluated using the microdilution checkerboard assay in combination with chemometric methods: principal components analysis and hierarchical cluster analysis. Sesquiterpene hydrocarbons were the most abundant compound class in the oil (67.2%), with β-elemene (40.4%) as the major compound. The essential oil exhibited slight antibacterial activity against the tested bacterial strains in vitro, but the combinations L. montana oil-chloramphenicol and L. montana oil-tetracycline exhibited mostly either synergistic or additive interactions. These combinations reduced the minimum effective dose of the antibiotics and, consequently, minimized their adverse side effects. In contrast, the association of L. montana essential oil and streptomycin was characterized by strong antagonistic interactions against Escherichia coli ATCC 25922. In the PCA and HCA analyses, streptomycin stood out and formed a separate group.

Download Full-text