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1.
Heliyon ; 10(6): e27431, 2024 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-38509897

RESUMO

"Intensification of Vaporization by Decompression to the Vacuum" (IVDV) has initially emerged as a technology primarily employed for expanding and enhancing the texture of biological products. However, its recent applications have showcased significant promise in the realm of extracting bioactive molecules from various plant materials. In this context, optimization using response surface methodology was conducted to investigate the impact of IVDV pretreatment on the extractability of phenolic compounds from Eryngium creticum leaves and stems, as well as their biological activities. Using IVDV preceding the extraction led to higher total phenolic content (TPC) and enhanced antiradical activities in treated materials compared to untreated ones. The optimal processing conditions in terms of water content, steam pressure and treatment time were determined in order to maximize TPC (89.07 and 20.06 mg GAE/g DM in leaves and stems, respectively) and antiradical (DPPH) inhibition percentage (93.51% and 27.54% in leaves and stems, respectively). IVDV-treated extracts showed superior antioxidant, antibacterial and antibiofilm capacities compared to raw extracts. Using RP-UHPLC-PDA-MS, caffeic acid and rosmarinic acid were identified in IVDV-treated leaves. IVDV can be implemented as an innovative treatment applied prior to extraction to boost the recovery of biomolecules from plant matrices.

2.
Int Microbiol ; 2023 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-37824024

RESUMO

Staphylococcus epidermidis, despite being a commensal of human skin and mucosa, is a major nosocomial pathogen implicated in device-associated infections. The dissemination of infection to other body sites is related to biofilm dispersal. This study focused on the dispersion stage of S. epidermidis CIP 444 biofilm, with the assessment of biofilm matrix composition in a time-dependent experiment (7 days extended) with 3 independent repetitions, using confocal laser scanning microcopy (CLSM) in association with ZEN 3.4 blue edition, COMSTAT, and ImageJ software. SYTO-9, propidium iodide (PI), DID'OIL, FITC, and calcofluor white M2R (CFW) were used to stain biofilm components. The results indicated that the biomass of dead cells increased from 15.18 ± 1.81 µm3/µm2 (day 3) to 23.15 ± 6.075 µm3/µm2 (day 4), along with a decrease in alive cells' biomass from 22.75 ± 2.968 µm3/µm2 (day 3) to 18.95 ± 5.713 µm3/µm2 (day 4). When the intensities were measured after marking the biofilm components, in a 24-h-old biofilm, polysaccharide made up the majority of the investigated components (52%), followed by protein (18.9%). Lipids make up just 11.6% of the mature biofilm. Protein makes up the largest portion (48%) of a 4-day-old biofilm, followed by polysaccharides (37.8%) and lipids (7.27%). According to our findings, S. epidermidis CIP 444 dispersion occurred on day 4 of incubation, and new establishment of the biofilm occurred on day 7. Remarkable changes in biofilm composition will pave the way for a new approach to understanding bacterial strategies inside biofilms and finding solutions to their impacts in the medical field.

3.
Front Cardiovasc Med ; 10: 1165302, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37719978

RESUMO

Vascular complications are the main cause of diabetes mellitus-associated morbidity and mortality. Oxidative stress and metabolic dysfunction underly injury to the vascular endothelium and myocardium, resulting in diabetic angiopathy and cardiomyopathy. Mitochondrial dysfunction has been shown to play an important role in cardiomyopathic disruptions of key cellular functions, including energy metabolism and oxidative balance. Both non-coding RNAs and RNA-binding proteins are implicated in diabetic cardiomyopathy, however, their impact on mitochondrial dysfunction in the context of this disease is largely unknown. Elucidating the effects of non-coding RNAs and RNA-binding proteins on mitochondrial pathways in diabetic cardiomyopathy would allow further insights into the pathophysiological mechanisms underlying diabetic vascular complications and could facilitate the development of new therapeutic strategies. Stem cell-based models can facilitate the study of non-coding RNAs and RNA-binding proteins and their unique characteristics make them a promising tool to improve our understanding of mitochondrial dysfunction and vascular complications in diabetes.

4.
Life (Basel) ; 13(6)2023 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-37374071

RESUMO

Extraction of polyphenols from Centranthus longiflorus stems was conducted using ultrasound and infrared Ired-Irrad® techniques, and compared to the conventional water bath method. Response surface methodology was used to analyse the effect of time, temperature, and ethanol percentage, as well as to optimize the three extraction methods. The highest phenolic content (81 mg GAE/g DM) and antioxidant activity (76% DPPH inhibition) were recorded with the Ired-Irrad® extract obtained under the optimal conditions: 55 °C, 127 min, 48% (v/v) ethanol. Biological activities (antioxidant, antibacterial and antibiofilm) of the three extracts were assessed. All C. longiflorus stems extracts showed limited antibacterial effects regardless of the extraction method (MIC = 50 mg/mL), whereas Ired-Irrad® extract exhibited the highest biofilm eradication and prevention capacities (93% against Escherichia coli and 97% against Staphylococcus epidermidis, respectively). This bioactivity is likely related to abundant caffeoylquinic acid and quercetin rutinoside, as identified by RP-UHPLC-PDA-MS analysis. The results obtained further promote the effectiveness of Ired-Irrad® as a highly flexible and cost-efficient extraction technique.

5.
Int J Mol Sci ; 23(23)2022 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-36499572

RESUMO

Diazotrophic bacteria isolated from the rhizosphere of a wild wheat ancestor, grown from its refuge area in the Fertile Crescent, were found to be efficient Plant Growth-Promoting Rhizobacteria (PGPR), upon interaction with an elite wheat cultivar. In nitrogen-starved plants, they increased the amount of nitrogen in the seed crop (per plant) by about twofold. A bacterial growth medium was developed to investigate the effects of bacterial exudates on root development in the elite cultivar, and to analyze the exo-metabolomes and exo-proteomes. Altered root development was observed, with distinct responses depending on the strain, for instance, with respect to root hair development. A first conclusion from these results is that the ability of wheat to establish effective beneficial interactions with PGPRs does not appear to have undergone systematic deep reprogramming during domestication. Exo-metabolome analysis revealed a complex set of secondary metabolites, including nutrient ion chelators, cyclopeptides that could act as phytohormone mimetics, and quorum sensing molecules having inter-kingdom signaling properties. The exo-proteome-comprised strain-specific enzymes, and structural proteins belonging to outer-membrane vesicles, are likely to sequester metabolites in their lumen. Thus, the methodological processes we have developed to collect and analyze bacterial exudates have revealed that PGPRs constitutively exude a highly complex set of metabolites; this is likely to allow numerous mechanisms to simultaneously contribute to plant growth promotion, and thereby to also broaden the spectra of plant genotypes (species and accessions/cultivars) with which beneficial interactions can occur.


Assuntos
Microbiologia do Solo , Triticum , Triticum/metabolismo , Raízes de Plantas/metabolismo , Rizosfera , Bactérias , Desenvolvimento Vegetal , Plantas , Nitrogênio/metabolismo , Exsudatos de Plantas/metabolismo
6.
Plants (Basel) ; 11(19)2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36235324

RESUMO

(1) Background: Eryngium creticum is a plant medicinally valued, and used in pharmacopeia to treat various diseases. No previous studies have been reported on E. creticum leaf extracts using an IR-assisted technique; thus, this study aimed to intensify polyphenol extraction using Ired-Irrad®, comparing it to the conventional water bath (WB) method. (2) Methods: Optimization of polyphenol extraction from E. creticum leaves was conducted using Response Surface Methodology. Ired-Irrad® was used and compared to the WB method. The biological activities (antiradical, antioxidant, antibacterial, and antibiofilm) of both extracts were assessed. UHPLC analysis was performed to analyze the phytochemical profile of both extracts. (3) Results: Under optimal conditions, IR improved the polyphenol extraction yield by 1.7 times, while lowering ethanol consumption by 1.5 times. Regarding the antibacterial activity, both WB and IR E. creticum leaf extracts exhibited the highest antibacterial activity against Staphylococcus epidermidis. The maximum biofilm prevention capacity was also noticed against S. epidermidis. UHPLC-MS analysis quantified two major phenolic compounds in both extracts: rutin and sinapic acid. (4) Conclusions: Ired-Irrad® technology proved to be an effective technique in intensifying polyphenol recovery, while preserving their quantity and quality.

7.
AMB Express ; 12(1): 128, 2022 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-36190582

RESUMO

The gastrointestinal tract is one of the most complex microbiological niches containing beneficial and non-pathogenic bacterial strains of which some may evolve into virulent under specific conditions. Lactobacillus rhamnosus GG is of the most known beneficial species with an ability to protect the intestine as opposed to Staphylococcus epidermidis 444 which causes serious health risks due to its high antimicrobial resistance. This study investigates first the survival and coexistence ability of L. rhamnosus GG, and S. epidermidis 444 at different pH levels. Subsequently, lysozyme's antimicrobial and antibiofilm effect on these two strains was elucidated before adding different concentrations of oxytetracycline hydrochloride antibiotic. Results showed that 50% inhibition of L. rhamnosus GG, S. epidermidis 444, and a co-culture of these planktonic strains were obtained respectively at a lysozyme concentration of 30, 18, and 26 mg/mL after the addition of ethylenediamine tetra-acetic acid (EDTA). At a pH of 7.5, mixing lysozyme (at IC50) and EDTA with oxytetracycline hydrochloride (700 µg/mL) showed an additional bactericidal effect as compared to its known bacteriostatic effect. Similarly, the addition of lysozyme to the antibiotic further increased the biofilm eradication of S. epidermidis 444 and L. rhamnosus GG where a maximal eradication of 70% was reached. Therefore, the potential development of new drugs based on adding a lysozyme-EDTA mixture to different types of antibiotics may be highly promising.

8.
Mater Sci Eng C Mater Biol Appl ; 121: 111876, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33579499

RESUMO

Device-Associated Healthcare-Associated Infections (DA-HAI) are a major threat to public health worldwide since they are associated with increased hospital stays, morbidity, mortality, financial burden, and hospital overload. A strategy to combat DA-HAI involves the use of medical devices endowed with surfaces that can kill or repel pathogens and prevent biofilm formation. We aimed to develop low-toxic protease-resistant anti-biofilm surfaces that can sensitize drug-resistant bacteria to sub-inhibitory concentrations of antibiotics. To this end, we hypothesized that polymyxin B nonapeptide (PMBN) could retain its antibiotic-enhancing potential upon immobilization on a biocompatible polymer, such as silicone. The ability of PMBN-coated silicone to sensitize a multidrug-resistant clinical isolate of Pseudomonas aeruginosa (strain Ps4) to antibiotics and block biofilm formation was assessed by viable counting, confocal microscopy and safranin uptake. These assays demonstrated that covalently immobilized PMBN enhances not only antibiotics added exogenously but also those incorporated into the functionalized coating. As a result, the functionalized surface exerted a potent bactericidal activity that precluded biofilm formation. PMBN-coated silicone displayed a high level of stability and very low cytotoxicity and hemolytic activity in the presence of antibiotics. We demonstrated for the first time that an antibiotic enhancer can retain its activity when covalently attached to a solid surface. These findings may be applied to the development of medical devices resistant to biofilm formation.


Assuntos
Preparações Farmacêuticas , Pseudomonas aeruginosa , Antibacterianos/farmacologia , Biofilmes , Testes de Sensibilidade Microbiana , Silicones
9.
Pak J Pharm Sci ; 33(1): 199-206, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32122849

RESUMO

Scorzonera have been confirmed to have potent bioactivity. Scorzonera mackmeliana (Asteraceae), the endemic plant to Lebanon, has not yet been investigated. In the present study, we assessed the antibacterial activity of S. mackmeliana extracts against referenced bacterial strains. Extracts from different parts of the plant were evaluated against Staphylococcus, Enterococcus, Escherichia and Pseudomonas species. Phytochemical screening was done by standard biochemical tests and minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and minimal biofilm eradication concentration (MBEC) were determined by micro dilution method. The extracts possessed mainly alkaloids, phenols, flavonoids and coumarins. Gram-negative bacteria were most sensitive, whose MICs ranged between 48.98 and 341.85 mg/ml. Water stems extract, rich in phenols, was the most active with an MIC of 48.98 mg/ml. MBC was only recorded for water flowers extract, rich in resins, against P. aeruginosa and ethanolic roots extract, rich in terpenoids, against S. epidermidis with values of 160.85 mg/ml and 284.35 mg/ml, respectively. Furthermore, antibiofilm activity showed that the lowest MBEC was 0.1 mg/ml for water stems extract with an eradication ability of 91% (p <0.0001). Hence, this study suggests S. mackmeliana as a promising candidate for future investigations to elucidate the major bioactive compound behind the antibacterial and antibiofilm effect.


Assuntos
Biofilmes/efeitos dos fármacos , Testes de Sensibilidade Microbiana/estatística & dados numéricos , Extratos Vegetais/farmacologia , Scorzonera/química , Antibacterianos/química , Antibacterianos/farmacologia , Flores/química , Extratos Vegetais/química , Folhas de Planta/química , Raízes de Plantas/química , Caules de Planta/química , Plantas/química
10.
Fitoterapia ; 137: 104274, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31344394

RESUMO

We have previously demonstrated that out of the butyrolactones series synthesized based on the natural lichen metabolite lichesterinic acid, compound (B-13) was the most effective against oral bacteria. However, its antibacterial mechanism is still unknown. In this study, we have investigated its bacterial localization by synthesizing a fluorescently labeled B-13 with NBD while maintaining its antibacterial activity. We showed that this compound binds to Streptococcus gordonii cell surface, as demonstrated by HPLC analysis. By adhering to cell surface, B-13 induced cell wall disruption leading to the release of bacterial constituents and consequently, the death of S. gordonii, a Gram-positive bacterium. A Gram-negative counterpart, Porphyromanas gingivalis, showed also cracked and ruptured cells in the presence of B-13. Besides, we also demonstrated that the analog of B-13, B-12, has also induced disruption of P. gingivalis and S. gordonii. This study revealed that butyrolactones can be considered as potent antibacterial compounds against oral pathogens causing medical complications.


Assuntos
Antibacterianos/farmacologia , Lactonas/farmacologia , Líquens/química , Porphyromonas gingivalis/efeitos dos fármacos , Streptococcus gordonii/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Estrutura Molecular
11.
Toxins (Basel) ; 11(6)2019 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-31146398

RESUMO

Aflatoxins (AF) are carcinogenic metabolites produced by different species of Aspergillus which readily colonize crops. AFM1 is secreted in the milk of lactating mammals through the ingestion of feedstuffs contaminated by aflatoxin B1 (AFB1). Therefore, its presence in milk, even in small amounts, presents a real concern for dairy industries and consumers of dairy products. Different strategies can lead to the reduction of AFM1 contamination levels in milk. They include adopting good agricultural practices, decreasing the AFB1 contamination of animal feeds, or using diverse types of adsorbent materials. One of the most effective types of adsorbents used for AFM1 decontamination are those of microbial origin. This review discusses current issues about AFM1 decontamination methods. These methods are based on the use of different bio-adsorbent agents such as bacteria and yeasts to complex AFM1 in milk. Moreover, this review answers some of the raised concerns about the binding stability of the formed AFM1-microbial complex. Thus, the efficiency of the decontamination methods was addressed, and plausible experimental variants were discussed.


Assuntos
Aflatoxina M1/química , Descontaminação/métodos , Contaminação de Alimentos/prevenção & controle , Leite/química , Adsorção , Aflatoxina M1/toxicidade , Animais , Bactérias/química , Humanos , Leveduras/química
12.
Adv Exp Med Biol ; 1117: 257-279, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30980362

RESUMO

Microbial cells show a strong natural tendency to adhere to surfaces and to colonize them by forming complex communities called biofilms. In this growth mode, biofilm-forming cells encase themselves inside a dense matrix which efficiently protects them against antimicrobial agents and effectors of the immune system. Moreover, at the physiological level, biofilms contain a very heterogeneous cell population including metabolically inactive organisms and persisters, which are highly tolerant to antibiotics. The majority of human infectious diseases are caused by biofilm-forming microorganisms which are responsible for pathologies such as cystic fibrosis, infective endocarditis, pneumonia, wound infections, dental caries, infections of indwelling devices, etc. AMPs are well suited to combat biofilms because of their potent bactericidal activity of broad spectrum (including resting cells and persisters) and their ability to first penetrate and then to disorganize these structures. In addition, AMPs frequently synergize with antimicrobial compounds and were recently reported to repress the molecular pathways leading to biofilm formation. Finally, there is a very active research to develop AMP-containing coatings that can prevent biofilm formation by killing microbial cells on contact or by locally releasing their active principle. In this chapter we will describe these strategies and discuss the perspectives of the use of AMPs as anti-biofilm agents for human therapy and prophylaxis.


Assuntos
Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Biofilmes , Humanos
13.
Appl Microbiol Biotechnol ; 102(15): 6687-6697, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29860592

RESUMO

This study aimed to investigate the ability of chitin and heat-treated shrimp shells to bind aflatoxin M1 (AFM1) in liquid matrix. Several concentrations of chitin or shrimp shells (grinded and ungrinded) were incubated in AFM1-contaminated phosphate-buffered saline (PBS) at different incubation times. The stability of the formed adsorbent-AFM1 complex was also tested in milk at different incubation times and temperatures. The unbound AFM1 was quantified by HPLC. Thereby, the percentages of the initial bounded AFM1 varied between 14.29 and 94.74%. Interestingly, in milk, an increase in incubation time coupled with a decrease in temperature affected positively the amount of bounded AFM1 to chitin and negatively those bounded to ungrinded shells. Results also revealed a partial reversibility in the binding of AFM1 to these adsorbents. These findings provided strong evidence on ability of chitin or shrimp shells by-product to bind AFM1 in milk and in PBS.


Assuntos
Aflatoxina M1/metabolismo , Exoesqueleto/química , Quitina/química , Contaminação de Alimentos/prevenção & controle , Aflatoxina M1/química , Animais , Inativação Metabólica , Leite/química , Alimentos Marinhos
14.
Braz. j. microbiol ; 49(1): 120-127, Jan.-Mar. 2018. tab, graf
Artigo em Inglês | LILACS | ID: biblio-889205

RESUMO

ABSTRACT Several strains of lactic acid bacteria (LAB), frequently used in food fermentation and preservation, have been reported to bind different types of toxins in liquid media. This study was carried out to investigate the effect of different concentrations of Lactobacillus rhamnosus GG (ATCC 53103) to bind aflatoxin M1 (AFM1) in liquid media. AFM1 binding was tested following repetitive washes or filtration procedures in combination with additional treatments such as heating, pipetting, and centrifugation. The mixture of L. rhamnosus GG and AFM1 was incubated for 18 h at 37 °C and the binding efficiency was determined by quantifying the unbound AFM1 using HPLC. The stability of the complexes viable bacteria-AFM1 and heat treated bacteria-AFM1 was tested. Depending on the bacterial concentration and procedure used, the percentages of bound AFM1 by L. rhamnosus GG varied from as low as undetectable to as high as 63%. The highest reduction in the level of unbound AFM1 was recorded for the five washes procedure that involved heating and pipetting. Results also showed that binding was partially reversible and AFM1 was released after repeated washes. These findings highlight the effect of different treatments on the binding of AFM1 to L. rhamnosus GG in liquid matrix.


Assuntos
Animais , Aflatoxina M1/química , Lacticaseibacillus rhamnosus/química , Aflatoxina M1/metabolismo , Meios de Cultura/química , Lacticaseibacillus rhamnosus/metabolismo
15.
Braz J Microbiol ; 49(1): 120-127, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-28843807

RESUMO

Several strains of lactic acid bacteria (LAB), frequently used in food fermentation and preservation, have been reported to bind different types of toxins in liquid media. This study was carried out to investigate the effect of different concentrations of Lactobacillus rhamnosus GG (ATCC 53103) to bind aflatoxin M1 (AFM1) in liquid media. AFM1 binding was tested following repetitive washes or filtration procedures in combination with additional treatments such as heating, pipetting, and centrifugation. The mixture of L. rhamnosus GG and AFM1 was incubated for 18h at 37°C and the binding efficiency was determined by quantifying the unbound AFM1 using HPLC. The stability of the complexes viable bacteria-AFM1 and heat treated bacteria-AFM1 was tested. Depending on the bacterial concentration and procedure used, the percentages of bound AFM1 by L. rhamnosus GG varied from as low as undetectable to as high as 63%. The highest reduction in the level of unbound AFM1 was recorded for the five washes procedure that involved heating and pipetting. Results also showed that binding was partially reversible and AFM1 was released after repeated washes. These findings highlight the effect of different treatments on the binding of AFM1 to L. rhamnosus GG in liquid matrix.


Assuntos
Aflatoxina M1/química , Lacticaseibacillus rhamnosus/química , Aflatoxina M1/metabolismo , Animais , Meios de Cultura/química , Lacticaseibacillus rhamnosus/metabolismo
16.
Fitoterapia ; 121: 164-169, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28736072

RESUMO

The oral bacteria not only infect the mouth and reside there, but also travel through the blood and reach distant body organs. If left untreated, the dental biofilm that can cause destructive inflammation in the oral cavity may result in serious medical complications. In dental biofilm, Streptococcus gordonii, a primary oral colonizer, constitutes the platform on which late pathogenic colonizers like Porphyromonas gingivalis, the causative agent of periodontal diseases, will bind. The aim of this study was to determine the antibacterial activity of eleven natural lichen compounds belonging to different chemical families and spanning from linear into cyclic and aromatic structures to uncover new antibiotics which can fight against the oral bacteria. The compounds were screened by broth microdilution assay. Three compounds were shown to have promising antibacterial activities where the depsidone core with certain functional groups constituted the best compound, psoromic acid, with the lowest MICs=11.72 and 5.86µg/mL against S. gordonii and P. gingivalis, respectively. The compounds screened had promising antibacterial activity which might be attributed to some important functional groups as discussed in our study. The best compounds did not induce the death of gingival epithelial carcinoma cells (Ca9-22). These results introduce new compounds having potent antibacterial activities against oral pathogens causing serious medical complications.


Assuntos
Antibacterianos/química , Líquens/química , Porphyromonas gingivalis/efeitos dos fármacos , Streptococcus gordonii/efeitos dos fármacos , Antibacterianos/isolamento & purificação , Biofilmes/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Boca/microbiologia , Doenças Periodontais/microbiologia
17.
J Intercult Ethnopharmacol ; 6(1): 50-57, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28163960

RESUMO

AIM: In a search for finding novel therapeutic agents, extracts from an endemic Lebanese plant, Astragalus angulosus, were evaluated for their potential in-vitro antibacterial and antibiofilm activities against three Gram-positive bacterial strains; Staphylococcus epidermidis (CIP444), Staphylococcus aureus (ATCC25923), and Enterococcus faecalis (ATCC29212); in addition to two Gram-negative strains, Escherichia coli (ATCC35218) and Pseudomonas aeruginosa (ATCC27853). MATERIALS AND METHODS: The plant was collected in April of 2013 and divided into several different portions, then its extracts were obtained by maceration using two different solvents. Extract analysis followed directly where microtiter broth dilution method was employed to assess antibacterial activity, while antibiofilm potential was tested using colorimetric method. RESULTS: Whole plant ethanolic extract showed the highest bacteriostatic effect at a concentration of 12.78 mg/ml and also was the most versatile exerting its effect against 3 different strains. Other extracts also exhibited an effect but at higher concentrations and each against a single strain. Regarding antibiofilm activity, the majority of the extracts were able to eradicate >50% of S. epidermidis preformed biofilm, where the highest activity was obtained with flower fraction extracted in water, achieving 67.7% biofilm eradication at 0.2 mg/ml. CONCLUSIONS: This plant possesses a promising potential in regard to eradicating bacteria and their biofilms and it is the first contributing step of establishing a library for the endemic Lebanese plants in this domain.

18.
Bioorg Med Chem ; 24(22): 5823-5833, 2016 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-27687969

RESUMO

Novel butyrolactone analogues were designed and synthesized based on the known lichen antibacterial compounds, lichesterinic acids (B-10 and B-11), by substituting different functional groups on the butyrolactone ring trying to enhance its activity. All synthesized butyrolactone analogues were evaluated for their in vitro antibacterial activity against Streptococcus gordonii. Among the derivatives, B-12 and B-13 had the lowest MIC of 9.38µg/mL where they have shown to be stronger bactericidals, by 2-3 times, than the reference antibiotic, doxycycline. These two compounds were then checked for their cytotoxicity against human gingival epithelial cell lines, Ca9-22, and macrophages, THP-1, by MTT and LDH assays which confirmed their safety against the tested cell lines. A preliminary study of the structure-activity relationships unveiled that the functional groups at the C4 position had an important influence on the antibacterial activity. An optimum length of the alkyl chain at the C5 position registered the best antibacterial inhibitory activity however as its length increased the bactericidal effect increased as well. This efficiency was attained by a carboxyl group substitution at the C4 position indicating the important dual role contributed by these two substituents which might be involved in their mechanism of action.


Assuntos
Antibacterianos/síntese química , Antibacterianos/farmacologia , Desenho de Fármacos , Lactonas/farmacologia , Streptococcus gordonii/efeitos dos fármacos , Antibacterianos/química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Lactonas/síntese química , Lactonas/química , Macrófagos/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-Atividade
19.
Carbohydr Polym ; 146: 282-91, 2016 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-27112876

RESUMO

Gluconacetobacter genera are valued for bacterial cellulose (BC) and acetic acid production. BC is produced at optimal yields in classical microbiological media that are expensive for a large scale of production. In addition, BC usage for industrial purposes is limited due to low conversion rate into cellulose and to long incubation duration. In this paper, Gluconacetobacter isolated from apple vinegar was kinetically studied to evaluate cellulose production in presence of different carbon sources. Acetic and citric acid effect on Gluconacetobacter metabolism is clarified. It was shown that Gluconacetobacter uses glucose as a primary carbon source for cells growth and products formation. Acetic acid employment as a co-carbon source in Hestrin Schramm medium showed an increase of 17% in BC yield with a moderate decrease in the crystallite size of the resulting polymer.


Assuntos
Carbono/metabolismo , Celulose/biossíntese , Meios de Cultura/química , Meios de Cultura/metabolismo , Gluconacetobacter/fisiologia , Microbiologia Industrial , Concentração de Íons de Hidrogênio
20.
Asian Pac J Trop Med ; 7S1: S546-52, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25312182

RESUMO

OBJECTIVE: To evaluate the antibacterial activity of the extracts of Laurus nobilis against three Gram-positive bacteria (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212 and Staphylococcus epidermidis CIP 444) and two Gram-negative bacteria (Escherichia coli ATCC 35218 and Pseudomonas aeruginosa ATCC 27853). Also, the antibiofilm activity has been investigated against the biofilm produced by Staphylococcus epidermidis CIP 444. MATERIALS: The polysaccharides, essential oil, and fatty oils extracted from the plant were used in broth microdilution methods to study the minimal inhibitory concentration, and then the minimal bactericidal concentration was determined. RESULTS: The results showed that alginate, fucoidan, fatty oils and essential oil have good antibacterial activities against the 5 bacterial strains, and a negligible biofilm eradication activity of fucoidan, laminaran, fatty oil, and essential oil was observed, but a promising biofilm eradication activity was obtained with alginate, which showed a reduced biofilm mass even at low concentration. CONCLUSIONS: The extracts obtained have promising antibacterial capacities which need further investigation for them to be incorporated in medical or nutritional applications.

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