Chemical Composition, and Evaluation of Antibacterial，Antibiofilm and Synergistic Effects with Conventional Antibiotics of Essential Oil from Mallotus repandus

The essential oil (EO) of aerial parts of Mallotus repandus (Willd.) Muell. Arg. was extracted by hydrodistillation and characterized by GC/FID and GC/MS. Fifty-one compounds comprising 97.1% of the EO were identified, of which α-humulene (18.7%), β-selinene (12.8%), aciphyllene (10.7%), (E)-caryophyllene (8.4%), α-copaene (5.5%), humulene epoxide II (4.9%) and caryophyllene oxide (4.3%) were the major compounds. The EO was evaluated for antibacterial properties using broth microdilution method and crystal-violet static biofilm formation assay. The M. repandus EO possessed a bactericidal effect against tested gram-positive bacteria strains (MIC = MBC: 0.05-0.10 mg/mL). Further, the EO showed the ability to inhibit the biofilm formation of Staphylococcus aureus. In addition, the potential synergistic effect was assessed by checkerboard method. Combination of the M. repandus EO with Streptomycin showed synergistic effects against the tested bacterial strains. This study demonstrates that M. repandus EO could be further explored as good alternative for potential pharmaceuticals.

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8-hydroxyquinoline-5-(N-4-chlorophenyl) sulfonamide and fluconazole combination as a preventive strategy for Candida biofilm in haemodialysis devices

Journal of Medical Microbiology ◽

10.1099/jmm.0.001377 ◽

2021 ◽

Vol 70 (7) ◽

Author(s):

Letícia Fernandes da Rocha ◽

Bruna Pippi ◽

Angélica Rocha Joaquim ◽

Saulo Fernandes de Andrade ◽

Alexandre Meneghello Fuentefria

Keyword(s):

Biofilm Formation ◽

Synergistic Effects ◽

Local Treatment ◽

The Other ◽

Antibiofilm Activity ◽

Preventive Strategy ◽

Clinical Issue ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Time Kill

Introduction. The presence of Candida biofilms in medical devices is a concerning and important clinical issue for haemodialysis patients who require constant use of prosthetic fistulae and catheters. Hypothesis/Gap Statement. This prolonged use increases the risk of candidaemia due to biofilm formation. PH151 and clioquinol are 8-hydroxyquinoline derivatives that have been studied by our group and showed interesting anti-Candida activity. Aim. This study evaluated the biofilm formation capacity of Candida species on polytetrafluoroethylene (PTFE) and polyurethane (PUR) and investigated the synergistic effects between the compounds PH151 and clioquinol and fluconazole, amphotericin B and caspofungin against biofilm cells removed from those materials. Further, the synergistic combination was evaluated in terms of preventing biofilm formation on PTFE and PUR discs. Methodology. Susceptibility testing was performed for planktonic and biofilm cells using the broth microdilution method. The checkerboard method and the time–kill assay were used to evaluate the interactions between antifungal agents. Antibiofilm activity on PTFE and PUR materials was assessed to quantify the prevention of biofilm formation. Results. Candida albicans, Candida glabrata and Candida tropicalis showed ability to form biofilms on both materials. By contrast, Candida parapsilosis did not demonstrate this ability. Synergistic interaction was observed when PH151 was combined with fluconazole in 77.8 % of isolates and this treatment was shown to be concentration- and time-dependent. On the other hand, indifferent interactions were predominantly observed with the other combinations. A reduction in biofilm formation on PUR material of more than 50 % was observed when using PH151 combined with fluconazole. Conclusion. PH151 demonstrated potential as a local treatment for use in a combination therapy approach against Candida biofilm formation on haemodialysis devices.

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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.

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Rosemary and Tea Tree Essential Oils Exert Antibiofilm Activities In Vitro against Staphylococcus aureus and Escherichia coli

Journal of Food Protection ◽

10.4315/0362-028x.jfp-19-337 ◽

2020 ◽

Vol 83 (7) ◽

pp. 1261-1267

Author(s):

TING LIU ◽

JINGFAN WANG ◽

XIAOMAN GONG ◽

XIAOXIA WU ◽

LIU LIU ◽

...

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Essential Oil ◽

Biofilm Formation ◽

Gas Chromatography Mass Spectrometry ◽

Tea Tree ◽

E Coli ◽

Microdilution Method ◽

Broth Microdilution Method

ABSTRACT The purpose of the present study was to determine the bioactive compounds in rosemary essential oil (REO) and tea tree essential oil (TEO) and to investigate their antibacterial and antibiofilm activities against Staphylococcus aureus and Escherichia coli in vitro. The MIC and MBC assays were performed to assess the antibacterial activity of these two EOs against S. aureus and E. coli with the broth microdilution method. A crystal violet assay was used to ascertain the effects of EOs on the biofilm formation of the test strains, and a tetrazolium bromide (MTT) assay was used to measure the level of inactivation of mature biofilms by EOs. Gas chromatography–mass spectrometry revealed 15 compounds in REO and 27 compounds in TEO, representing 97.78 and 98.13% of the total EO, respectively. Eucalyptol and α-pinene were found in high concentrations in REO, and the two major compounds in TEO were 4-terpineol and terpinolene. The MICs of REO for the two S. aureus and E. coli test strains were both 0.5 mg/mL, and the MICs of TEO for the two strains were both 0.25 mg/mL. Therefore, these EOs can significantly inhibit the formation of biofilms and induced morphological biofilm changes, as verified by scanning electron microscopy. Both EOs had destructive effects on the mature biofilm of the two test strains. TEO was more inhibitory than REO for biofilm formation by the two test strains. HIGHLIGHTS

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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.

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Synergy between Essential Oils of Calamintha Species (Lamiaceae) and Antibiotics

Natural Product Communications ◽

10.1177/1934578x1801300325 ◽

2018 ◽

Vol 13 (3) ◽

pp. 1934578X1801300 ◽

Cited By ~ 2

Author(s):

Marina Milenković ◽

Jelena Stošović ◽

Violeta Slavkovska

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Activity ◽

Antibacterial Activity ◽

Essential Oil ◽

Essential Oils ◽

Broth Microdilution ◽

Bacterial Strains ◽

Microdilution Method ◽

Broth Microdilution Method ◽

The Subject

The subject of the study was the investigation of the chemical composition and antimicrobial activity of the essential oils (EOs) isolated from Calamintha sylvatica, C. vardarensis, C. nepeta and C. glandulosa, as well as their antibacterial activity in combination with antibiotics. The quantitative and qualitative analysis of EOs was performed using the GC/FID and GC/MS methods. The antimicrobial activity of EOs against six standard bacterial strains and one strain of yeast was tested using the broth microdilution method, while the antimicrobial activity of a combination of essential oils and gentamicin/ciprofloxacin was tested by the checkerboard method. The dominant components (> 10%) of the essential oils were: cis-piperitone epoxide and menthone ( C. sylvatica), pulegone and menthone ( C. vardarensis), pulegone and piperitenone ( C. nepeta), pulegone, piperitenone, menthone and piperitone ( C. glandulosa). EOs did not exhibit significant antimicrobial activity except the essential oil of C. vardarensis which was selectively active against Staphylococcus aureus (MIC - 21.25 μg/mL). The overall effect of essential oil-antibiotic combinations varied from synergistic (FICI ≤ 0.5) to antagonistic (FICI ≥ 2) depending on the bacterial strain tested.

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GC-FID Analysis and Antibacterial Activity of the Calyptranthes concinna Essential Oil against MDR Bacterial Strains

Separations ◽

10.3390/separations7010010 ◽

2020 ◽

Vol 7 (1) ◽

pp. 10

Author(s):

Maria do Socorro Costa ◽

Nara Juliana Santos Araújo ◽

Thiago Sampaio de Freitas ◽

Francisco Assis Bezerra da Cunha ◽

Wanderlei do Amaral ◽

...

Keyword(s):

Antibacterial Activity ◽

Essential Oil ◽

Inhibitory Concentration ◽

Chemical Constituents ◽

Antibiotic Activity ◽

Bacterial Strains ◽

Microdilution Method ◽

Multiresistant Bacteria ◽

Broth Microdilution Method ◽

Mic Value

Presently, results from a study carried out in this area using the essential oil from the Calyptranthes concinna species, a representative from the Myrtaceae family, are reported. The essential oil was obtained by hydrodistillation and gas chromatography coupled to mass spectrometry was used to identify its chemical constituents. Antibacterial activity was determined using the broth microdilution method, thus obtaining the Minimal Inhibitory Concentration (MIC) value, from which the subinhibitory concentration (MIC/8) was derived. The C. concinna essential oil presented antibacterial activity against both standard and multiresistant bacteria. In addition, the oil demonstrated an antibiotic activity potentiation against Staphylococcus aureus and Escherichia coli when in combination with the antibiotic gentamicin, reducing the MIC from 141.38 μg/mL and 208.63 μg/mL to 64 μg/mL and 128 μg/mL, respectively. Conclusions: Findings from the present study suggest this oil is promising in terms of its antimicrobial activity.

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α-Terpinyl Acetate: Occurrence in Essential Oils Bearing Thymus pulegioides, Phytotoxicity, and Antimicrobial Effects

Molecules ◽

10.3390/molecules26041065 ◽

2021 ◽

Vol 26 (4) ◽

pp. 1065

Author(s):

Vaida Vaičiulytė ◽

Kristina Ložienė ◽

Jurgita Švedienė ◽

Vita Raudonienė ◽

Algimantas Paškevičius

Keyword(s):

Essential Oil ◽

Essential Oils ◽

Poa Pratensis ◽

Antimicrobial Effect ◽

Forage Legume ◽

Economic Productivity ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Phytotoxic Effect ◽

Lower Effect

The aim of this study was to evaluate occurrence of T. pulegioides α-terpinyl acetate chemotype, as source of natural origin α-terpinyl acetate, to determine its phytotoxic and antimicrobial features. Were investigated 131 T. pulegioides habitats. Essential oils were isolated by hydrodistillation and analyzed by GC-FID and GC-MS. Phytotoxic effect of essential oil of this chemotype on monocotyledons and dicotyledons through water and air was carried out in laboratory conditions; the broth microdilution method was used to screen essential oil effect against human pathogenic microorganisms. Results showed that α-terpinyl acetate was very rare compound in essential oil of T. pulegioides: it was found only in 35% of investigated T. pulegioides habitats. α-Terpinyl acetate (in essential oil and pure) demonstrated different behavior on investigated plants. Phytotoxic effect of α-terpinyl acetate was stronger on investigated monocotyledons than on dicotyledons. α-Terpinyl acetate essential oil inhibited seeds germination and radicles growth for high economic productivity forage grass monocotyledon Poa pratensis, but stimulated seed germination for high economic productive forage legume dicotyledon Trifolium pretense. α-Terpinyl acetate essential oil showed high antimicrobial effect against fungi and dermatophytes but lower effect against bacteria and Candida yeasts. Therefore, T. pulegioides α-terpinyl acetate chemotype could be a potential compound for developing preventive measures or/and drugs for mycosis.

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Antimicrobial Essential Oil Combinations to Combat Foot Odour

Planta Medica ◽

10.1055/a-0592-8022 ◽

2018 ◽

Vol 84 (09/10) ◽

pp. 662-673 ◽

Cited By ~ 4

Author(s):

Ané Orchard ◽

Alvaro Viljoen ◽

Sandy van Vuuren

Keyword(s):

Antimicrobial Activity ◽

Essential Oil ◽

Essential Oils ◽

Antimicrobial Efficacy ◽

Juniperus Virginiana ◽

Broth Microdilution ◽

Synergistic Interactions ◽

Microdilution Method ◽

Broth Microdilution Method

AbstractFoot odour (bromodosis) is an embarrassing and perplexing condition mostly caused by bacteria of the Brevibacterium species. Essential oils are a credible option as an affordable treatment of odour and contribute towards antimicrobial efficacy. Therefore, this study sets out to investigate the antimicrobial activity of essential oil combinations against odour-causing bacteria. The broth microdilution method was used to investigate the antimicrobial activity of 119 essential oil combinations, and the fractional inhibitory index was calculated to determine the interactive profile. Combinations that resulted in synergy in 1 : 1 ratios were further evaluated in different concentrations, and isobolograms were plotted to determine the influence of the ratio on overall activity. Numerous combinations could be identified as having synergistic interactions against the Brevibacterium spp. and no antagonism was observed. The combination of Juniperus virginiana (juniper) and Styrax benzoin (benzoin) demonstrated synergy against all three Brevibacterium spp. tested and J. virginiana was the essential oil responsible for the majority of the synergistic interactions. The results reported here confirm the promising potential of the majority of these oils and selected combinations in treating and controlling bromodosis.

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Action ofCoriandrum sativumL. Essential Oil upon OralCandida albicansBiofilm Formation

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2011/985832 ◽

2011 ◽

Vol 2011 ◽

pp. 1-9 ◽

Cited By ~ 38

Author(s):

V. F. Furletti ◽

I. P. Teixeira ◽

G. Obando-Pereda ◽

R. C. Mardegan ◽

A. Sartoratto ◽

...

Keyword(s):

Essential Oil ◽

Biofilm Formation ◽

Plant Material ◽

Inhibitory Concentration ◽

Chemical Characterization ◽

Synergistic Action ◽

Biofilm Growth ◽

Water Distillation ◽

Microdilution Method

The efficacy of extracts and essential oils fromAllium tuberosum, Coriandrum sativum, Cymbopogon martini, Cymbopogon winterianus,andSantolina chamaecyparissuswas evaluated againstCandidaspp. isolates from the oral cavity of patients with periodontal disease. The most active oil was fractionated and tested againstC. albicansbiofilm formation. The oils were obtained by water-distillation and the extracts were prepared with macerated dried plant material. The Minimal Inhibitory Concentration—MIC was determined by the microdilution method. Chemical characterization of oil constituents was performed using Gas Chromatography and Mass Spectrometry (GC-MS). C. sativum activity oil upon cell and biofilm morphology was evaluated by Scanning Electron Microscopy (SEM). The best activities against planktonicCandidaspp. were observed for the essential oil and the grouped F8–10fractions fromC. sativum. The crude oil also affected the biofilm formation inC. albicanscausing a decrease in the biofilm growth. Chemical analysis of the F8–10fractions detected as major active compounds, 2-hexen-1-ol, 3-hexen-1-ol and cyclodecane. Standards of these compounds tested grouped provided a stronger activity than the oil suggesting a synergistic action from the major oil constituents. The activity ofC. sativumoil demonstrates its potential for a new natural antifungal formulation.

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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.

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