RESUMO
Plaque psoriasis is a chronic inflammatory skin disease causing red inflamed lesions covered by scales. Leukocytes, including dendritic cells and T cells, participate in the inflammation of the skin by producing multiple cytokines, thus contributing to the hyperproliferation of keratinocytes. Lack of effectiveness and toxic side effects are the main concerns with conventional treatments, and research involving new antipsoriatic molecules is essential. In this study, the anti-inflammatory and antiproliferative effects of two natural polyphenols, phloretin and balsacone C, were investigated using the coculture of T cells and psoriatic keratinocytes. Phloretin exerted antiproliferative activity by regulating the expression of antigen Ki67 and proliferating cell nuclear antigen (PCNA). These effects were comparable to those of methotrexate, a reference treatment for moderate to severe psoriasis. With balsacone C, the expression of Ki67 was also reduced. Additionally, phloretin decreased the levels of multiple pro-inflammatory cytokines: monocyte chemoattractant protein-1 (MCP-1/CCL2), macrophage inflammatory protein-1α (MIP-1α), granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-1 alpha (IL-1α), interleukin-1 beta (IL-1ß), interleukin-6 (IL-6), interleukin-17A (IL-17A), and tumor necrosis factor alpha (TNF-α). The increased interleukin-2 (IL-2) levels with phloretin and methotrexate also represented anti-inflammatory activity. Balsacone C and methotrexate decreased the levels of IL-1α and IL-1ß, but methotrexate exerted a higher reduction. In summary, the anti-inflammatory effects of phloretin were more pronounced than those of methotrexate and balsacone C. In addition, the expression of lymphocyte common antigen (CD45) was more similar to that of the healthy condition after using phloretin or methotrexate. Finally, phloretin stood out from the other compounds and appears promising for psoriasis treatment.
Assuntos
Anti-Inflamatórios , Proliferação de Células , Técnicas de Cocultura , Citocinas , Queratinócitos , Floretina , Psoríase , Linfócitos T , Humanos , Floretina/farmacologia , Psoríase/tratamento farmacológico , Psoríase/metabolismo , Psoríase/patologia , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismo , Anti-Inflamatórios/farmacologia , Proliferação de Células/efeitos dos fármacos , Linfócitos T/efeitos dos fármacos , Linfócitos T/metabolismo , Linfócitos T/imunologia , Citocinas/metabolismo , Polifenóis/farmacologia , Metotrexato/farmacologia , Células CultivadasRESUMO
Ursolic acid and uvaol are naturally occurring triterpenoids that exhibit a broad spectrum of pharmacological activities, including cytotoxicity. However, a primary challenge in the development of ursane-type pentacyclic triterpenoids for pharmacological use is their poor aqueous solubility, which can impede their effectiveness as therapeutics agents. In this study, we present the facile synthesis of ursolic acid monodesmosides and uvaol bidesmosides, incorporating naturally occurring and water-soluble pentoses and deoxyhexose sugar moieties of opposite d- and l-configurations at the C3 or C3/C28 positions of the ursane core. The twenty synthetic saponins were evaluated in vitro for their cytotoxicity against lung carcinoma (A549) and colorectal adenocarcinoma (DLD-1) cell lines. Notably, all the bidesmosidic uvaol saponins were shown to be cytotoxic as compared to their non-cytotoxic parent triterpenoid. For each series of ursane-type saponins, the most active compounds were 3-O-α-l-arabinopyranosyl ursolic acid (3h) and 3,28-di-O-α-l-rhamnopyranosyl uvaol (4f), showing IC50 values in the low micromolar range against A549 and DLD-1 cancer lines.
Assuntos
Ensaios de Seleção de Medicamentos Antitumorais , Saponinas , Triterpenos , Humanos , Saponinas/farmacologia , Saponinas/síntese química , Saponinas/química , Triterpenos/química , Triterpenos/farmacologia , Triterpenos/síntese química , Linhagem Celular Tumoral , Relação Estrutura-Atividade , Antineoplásicos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Estrutura Molecular , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Triterpenos PentacíclicosRESUMO
We present the isolation and structural characterization of a novel nonionic dirhamnolipid methyl ester produced by the bacterium Burkholderia lata. The structure and the absolute configuration of the isolated dirhamnolipid bearing a symmetrical C14-C14 methyl ester chain were thoroughly investigated through chemical degradation and spectroscopic methods including 1D and 2D NMR analysis, HR-ESI-TOF-MS, chiral GC-MS, and polarimetry. Our work represents the first mention in the literature of a rhamnolipid methyl ester from Burkholderia species.
Assuntos
Burkholderia , Glicolipídeos , Glicolipídeos/química , Burkholderia/química , Cromatografia Gasosa-Espectrometria de Massas , Ésteres/metabolismoRESUMO
The current study aimed to evaluate Tunisian Tamarix africana Poir biological activities. In this study, novel biological activities of the shoot extracts related to their phenolics investigated. Secondary metabolite contents, antioxidant, anti-inflammatory and cytotoxic activities of four extracts (hexane, dichloromethane, methanol and water) were investigated. Antioxidant activities were assessed via in vitro and ex vivo assays. Besides, anticancer activity was investigated against human lung carcinoma (A-549) and colon adenocarcinoma (DLD-1) cells. The anti-inflammatory ability was evaluated via inhibition of LPS-induced NO production in RAW 264.7 macrophage cell lines. Methanol and water extracts displayed the highest antioxidant (IC50 = 3.3 and 4.3 µg/mL respectively), which are correlated activities correlated with phenolic contents. Hexane extract exhibited an important anti-inflammatory effect inhibiting NO ability by 100% at 80 µg/mL. Besides, T. africana extracts were found to be active against A-549 lung carcinoma cells with IC50 values ranging from 20 to 34 µg/mL. These results suggested that T. africana is considered as a potential source of readily accessible natural molecules with a promising effect on human health and diseases.
Assuntos
Adenocarcinoma , Neoplasias do Colo , Tamaricaceae , Humanos , Antioxidantes/farmacologia , Antioxidantes/química , Tamaricaceae/química , Hexanos , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Metanol , Anti-Inflamatórios/farmacologia , Compostos Fitoquímicos/farmacologia , ÁguaRESUMO
Hydrofluoric acid (HF) is a ubiquitous industrial chemical that is particularly hazardous because of the potential for systemic effects and the induction of severe cutaneous necrosis after contact with the skin. Minimizing skin injury requires decontaminating the affected area promptly with an emergency rinsing solution. Few experimental studies have objectively characterized rinsing solutions such as Diphoterine (DP). Here we develop an ex vivo pigskin model to study and compare the efficacy of rinsing solutions as initial decontaminating agents to stop the progression of skin lesions after HF splashing. The pigskin model shows an immediate local response to HF at varying concentrations and exposure times. We then exposed the pigskin biopsies to 3.75% HF for 1â¯min and rinsed them with different solutions, including water, 0.9% NaCl solution (saline), 10% calcium gluconate (CaG), Hexafluorine (HXF), and DP. We found DP to be a more effective agent for decontaminating HF lesions than water, saline, and CaG. DP had a similar efficacy as HXF, an emergency rinsing solution used specifically for decontaminating HF-exposed skin. This study shows that skin exposed to HF must be treated quickly from the first minute of exposure.
Assuntos
Queimaduras Químicas , Compostos de Flúor , Humanos , Ácido Fluorídrico , Queimaduras Químicas/terapia , Gluconato de Cálcio , Solução Salina , Água , Compostos OrgânicosRESUMO
Three original derivatives of the cytotoxic betulinic acid 3-O-α-l-rhamnopyranoside featuring a monomethylated rhamnoside residue were synthesized. An improved catalytic procedure was involved to functionalize the O-3 position of the monosaccharide in a site-selective fashion. The cytotoxicity of the novel compounds was evaluated in vitro to highlight the moderate impact of carbohydrate monomethylation on the biological activity of betulinic acid 3-O-α-l-rhamnopyranoside.
RESUMO
The chemical compositions of eleven wild species of aromatic and medicinal plants indigenous to Algeria, including Thymus, Mentha, Rosmarinus, Lavandula, and Eucalyptus, were analyzed. The identification of the chemical composition of each oil was conducted using GC-FID and GC-MS capillary gas chromatography. The study investigated the chemical variability of the essential oils based on several parameters. These included the impact of the vegetative cycle on oil composition, variations among subspecies of the same species, variations among species within the same genus, the influence of environmental factors on composition variations within a species, chemo typing, and the genetic factors (such as hybridization) contributing to chemical variability. The concepts of chemotaxonomy, chemotype, and chemical markers were examined to understand their limitations and emphasize the importance of regulating the use of essential oils derived from wild plants. The study advocates for an approach that involves the domestication of wild plants and screening their chemical compositions according to more specific standards for each commercially available oil. Lastly, the nutritional implications and the variability of nutritional impact based on the chemical composition of the essential oils will be discussed.
Assuntos
Óleos Voláteis , Plantas Medicinais , Óleos Voláteis/química , Óleos de Plantas/química , Cromatografia Gasosa-Espectrometria de Massas , Cromatografia GasosaRESUMO
Lycium europaeum is used as a medicinal herb in many countries. In this study, cyclohexane, dichloromethane, ethyl acetate, methanol and water were used as solvents in the extraction of L. europaeum fruits. The contents of total phenolics, total ï¬avonoids, total tannins and condensed tannins as well as the biological activities of these extracts were investigated using various in vitro and ex vivo assays. Results showed that all solvent extracts of L. europaeum had no anticancer activity against cancerous (A-549 and DLD-1) and non-cancerous (WS-1) human cells. Methanol and ethyl acetate were the most effective solvent for extraction of phenolic compounds and also exhibited the highest antioxidant and anti-inflammatory activities. The methanol extract of L. europaeum fruits was the richest in phenolic compounds with the predominance of ferulic acid, catechin and narengin. These results supported the use of L. europaeum fruit as natural source of bioactive compound for pharmaceutical applications.
Assuntos
Antioxidantes , Lycium , Humanos , Antioxidantes/análise , Metanol/química , Frutas/química , Lycium/química , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Solventes , Compostos Fitoquímicos/farmacologia , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/análise , Fenóis/farmacologia , Fenóis/análiseRESUMO
Dirchromone is a bioactive vinyl sulfoxide-bearing chromone first isolated from the shrub Dirca palustris. Altogether, 32 of its derivatives were prepared to assess the effect of substitution of its chromone core upon activities against cancer cell lines, Gram-positive bacteria, and fungi (such as Candida albicans). All compounds were synthesized following a synthetic strategy involving Pummerer and soft-enolization Baker-Venkataraman rearrangements. Substituent position changes induced little variability on the activities tested. There was no correlation between cytotoxic and antibacterial effects, suggesting different underlying mechanisms of action. In particular, hydroxy group and cyanide substituents diminished cytotoxicity, with the latter featuring enhanced antibacterial activity. Higher homologues of 6-alkoxydirchromones also exhibited progressively emerging antifungal activity. Other modifications had moderate effects on cytotoxicity with some derivatives leading to increased potency. This behavior highlights the robustness of the natural dirchromone pharmacophore toward decoration, thus paving the way for more elaborate future drug design.
Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antineoplásicos/farmacologia , Cromonas/farmacologia , Linhagem Celular Tumoral , Cromonas/síntese química , Cromonas/química , Humanos , Relação Estrutura-AtividadeRESUMO
Over 15 years, with the support of a Canadian funding agency, the Universidad Mayor de San Simón, in Bolivia, undertook a large survey of aromatic plants of the South American country. More than a hundred species were studied under various aspects, including the production and characterization of essential oils. As part of this survey, the chemical composition of an essential oil sample obtained from Pentacalia herzogii (Asteraceae) growing wild in the High Valley region of the department of Cochabamba was determined by a combination of GC and GC-MS measurements. α-Pinene was the main constituent of this essential oil (34%), accompanied by limonene (22%) and germacrene D (7.5%) as well as an important fraction of methoxylated monoterpenoids. They were mainly isomers of thymol methyl ether, accounting for 13% of the chromatogram. A new quantitatively important compound (9%) was identified through NMR and chemical synthesis as 4-isopropyl-6-methylbenzo[d][1,3]dioxole, and designated herzogole, alongside the minor related compound 1-isopropyl-2,3-dimethoxy-5-methylbenzene. The monoterpene benzodioxole featured a distinctive green-phenolic aroma which could raise interest for fragrance use. Since these compounds were not known naturally, a biosynthetic mechanism of their formation was proposed and put in perspective to illustrate the metabolic originality of P. herzogii.
Assuntos
Asteraceae/química , Benzodioxóis/isolamento & purificação , Óleos Voláteis/análise , Monoterpenos Bicíclicos/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas , Limoneno/isolamento & purificação , Monoterpenos/isolamento & purificação , Óleos Voláteis/química , Componentes Aéreos da Planta/química , Óleos de Plantas/análise , Óleos de Plantas/química , Sesquiterpenos de Germacrano/isolamento & purificaçãoRESUMO
Skin aging is the most visible element of the aging process, giving rise to a major concern for many people. Plants from the Ericaceae family generally have antioxidant and anti-inflammatory properties, making them potential anti-aging active ingredients. This study aimed to evaluate the safety and anti-aging efficacy of a Kalmia angustifolia extract using reconstructed skin substitutes. The safety evaluation was performed using a 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay, while the efficacy was determined by assessing antioxidant and anti-inflammatory activity and analyzing skin substitutes reconstructed according to the self-assembly method by histology and immunofluorescence staining (elastin, collagen-1, collagen-3, aquaporin-3). The cell viability assay established the safety of the extract at a concentration up to 200 µg/mL. The Oxygen Radical Absorbance Capacity (ORAC) assay and a cell-based assay using 2',7'-dichlorofluorescein-diacetate (DCFH-DA) revealed a strong antioxidant activity with an ORAC value of 16 µmol Trolox Equivalent/mg and a half-maximal inhibitory concentration (IC50) of 0.37 ± 0.02 µg/mL, while an interesting anti-inflammatory activity was found in the inhibition of NO production, with an inhibition percentage of NO production of 49 ± 2% at 80 µg/mL. The isolation and characterization of the extract allowed the identification of compounds that could be responsible for these biological activities, with two of them being identified for the first time in K. angustifolia: avicularin and epicatechin-(2ß-O-7, 4ß-6)-ent-epicatechin. Histological analyses of skin substitutes treated with the extract showed an increase in dermal thickness compared with the controls. K. angustifolia extract enhanced the expression of elastin and collagen-1, which are usually decreased with skin aging. These results suggest that K. angustifolia has promising antioxidant efficacy and anti-aging potential.
RESUMO
UV-B and IR-A radiation are important inducers of biological changes in skin involving ROS generation. The overloading of antioxidant defense mechanisms by ROS production could lead to photoaging and photocarcinogenesis processes. Various traditional usages are reported for Aralia nudicaulis L. extracts, including treatment of dermatological disorders. Antioxidant and anti-inflammatory properties have already been reported for other Aralia species possibly due to the presence of phenolic compounds. However, the phenolic composition and the potential activity of A. nudicaulis rhizomes extract against oxidative stress and UV/IR damages have not been investigated. The main aims of this study were to prepare a fraction enriched in phenolic compounds (FEPC) from A. nudicaulis rhizomes, to identify its major phenolic compounds and to assess its potential for protective effects against oxidative stress induced by UV-B, IR-A or inflammation. A quantitative LC-MS study of FEPC shows that chlorogenic, caffeic and protocatechuic acids are the main phenolic compounds present, with concentrations of 15.6%, 15.3% and 4.8% of the total composition, respectively. With a validated analytical method, those compounds were quantified over different stages of the growing period. As for biological potential, first this extract demonstrates antioxidant and anti-inflammatory activities. Furthermore, ROS generation induced by IR-A and UV-B were strongly inhibited by A. nudicaulis extract, suggesting that Aralia nudicaulis L. rhizome extract could protect dermal cells against oxidative stress induced by UV-B and IR-A.
Assuntos
Antioxidantes/farmacologia , Aralia/química , Fibroblastos/efeitos dos fármacos , Fenóis/farmacologia , Extratos Vegetais/farmacologia , Pele/efeitos dos fármacos , Anti-Inflamatórios/farmacologia , Linhagem Celular , Fibroblastos/citologia , Humanos , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Rizoma/química , Pele/citologiaRESUMO
Carbamate-bearing carbohydrates contribute to the pharmacological properties of various natural glycosides. The catalytic site-selective carbamoylation of minimally protected pyranosides was achieved for the first time to bypass protection/deprotection sequences. 1-Carbamoylimidazoles were used as the carbamoylation reagents to circumvent the harmful and unstable phosgene and isocyanates. This borinic acid catalyzed transformation granted an expedient access to the tumor cell-binding carbamoylmannoside moiety of bleomycins and analogs in yields of 56% to 89%.
RESUMO
The use of growth-promoting antibiotics in livestock faces increasing scrutiny and opposition due to concerns about the increased occurrence of antibiotic-resistant bacteria. Alternative solutions are being sought, and plants of Lamiaceae may provide an alternative to synthetic antibiotics in animal nutrition. In this study, we extracted essential oil from Monarda didyma, a member of the Lamiaceae family. We examined the chemical composition of the essential oil and then evaluated the antibacterial, antioxidant, and anti-inflammatory activities of M. didyma essential oil and its main compounds in vitro. We then evaluated the effectiveness of M. didyma essential oil in regard to growth performance, feed efficiency, and mortality in both mice and broilers. Carvacrol (49.03%) was the dominant compound in the essential oil extracts. M. didyma essential oil demonstrated antibacterial properties against Escherichia coli (MIC = 87 µg·mL-1), Staphylococcus aureus (MIC = 47 µg·mL-1), and Clostridium perfringens (MIC = 35 µg·mL-1). Supplementing the diet of mice with essential oil at a concentration of 0.1% significantly increased body weight (+5.4%) and feed efficiency (+18.85%). In broilers, M. didyma essential oil significantly improved body weight gain (2.64%). Our results suggest that adding M. didyma essential oil to the diet of broilers offers a potential substitute for antibiotic growth promoters.
Assuntos
Antibacterianos/administração & dosagem , Monarda/química , Óleos Voláteis/administração & dosagem , Óleos de Plantas/administração & dosagem , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Peso Corporal/efeitos dos fármacos , Galinhas , Clostridium perfringens/efeitos dos fármacos , Cimenos , Suplementos Nutricionais/análise , Escherichia coli/efeitos dos fármacos , Masculino , Camundongos , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Óleos de Plantas/química , Óleos de Plantas/farmacologia , Staphylococcus aureus/efeitos dos fármacosRESUMO
Chemical composition and herbicidal, antifungal, antibacterial and molluscicidal activities of essential oils from Choukzerk, Eryngium triquetrum, and Alexander, Smyrnium olusatrum, from western Algeria were characterized. Capillary GC-FID and GC/MS were used to investigate chemical composition of both essential oils, and the antifungal, antibacterial, molluscicidal and herbicidal activities were determined by % inhibition. Collective essential oil of E. triquetrum was dominated by falcarinol (74.8%) and octane (5.6%). The collective essential oil of S. olusatrum was dominated by furanoeremophilone (31.5%), furanodiene+curzurene (19.3%) and (E)-ß-caryophyllene (11%). The E. triquetrum oil was tested and a pure falcarinol (99%) showed virtuous herbicidal and antibacterial activities against potato blackleg disease, Pectobacterium atrosepticum, and Gram-negative soil bacterium, Pseudomonas cichorii (85 and 100% inhibition, respectively), and high ecotoxic activity against brine shrimp, Artemia salina, and the freshwater snail, Biomphalaria glabrata, with an IC50 of 0.35 µg/mL and 0.61 µg/mL, respectively. Essential oil of S. olusatrum showed interesting antibacterial and ecotoxic activity and good herbicidal activity against watercress seeds, Lepidium sativum (74% inhibition of photosynthesis, 80% mortality on growth test on model watercress), while the furanoeremophilone isolated from the oil (99% pure) showed moderate herbicidal activity. Both oils showed excellent antifungal activity against Fusarium. Both oils and especially falcarinol demonstrated good potential as new biocontrol agents in organic crop protection.
RESUMO
Several families of naturally occurring C-alkylated dihydrochalcones display a broad range of biological activities, including antimicrobial and cytotoxic properties, depending on their alkylation sidechain. The catalytic Friedel-Crafts alkylation of the readily available aglycon moiety of neohesperidin dihydrochalcone was performed using cinnamyl, benzyl, and isoprenyl alcohols. This procedure provided a straightforward access to a series of derivatives that were structurally related to natural balsacones, uvaretin, and erioschalcones, respectively. The antibacterial and cytotoxic potential of these novel analogs was evaluated in vitro and highlighted some relations between the structure and the pharmacological properties of alkylated dihydrochalcones.
RESUMO
Analogs of dirchromone were prepared to shed light on the pivotal role of its peculiar vinylsulfoxide side chain towards its cytotoxic and antimicrobial properties, especially dependant upon the presence and oxidation state of sulfur. The reaction of dirchromone with cysteamine revealed a surprising Michael acceptor behavior with elimination of the methylsulfinyl moiety and redox transformation of the sulfur atom that could be involved in the mode of action of dirchromone within cells.
Assuntos
EnxofreRESUMO
Five batches of resin from the Pili tree (Canarium ovatum Engl.) were distilled, and their essential oils and hydrosols were analyzed by gas chromatography. The oils, obtained in yields of 13.4-19.7 % v/m, featured α-phellandrene in high proportions (50-65 %), alongside limonene, ß-phellandrene and para-cymene. Chiral GC analysis confirmed that both phellandrenes were in fact >95 % (S)-(+) enantiomers, while the other monoterpenes featured less pronounced enantiomeric excesses. The hydrosols were rich in α-phellandrene oxidation products including cis-α-phellandrene epoxide and a series of para-menth-5-ene-1,2-diol isomers. Both essential oils and hydrosols were tested for their antibacterial activity against Escherichia coli and Staphylococcus aureus and exhibited MIC90 of less than 5 and 0.5â mg/mL of total volatiles, respectively. The essential oil features some potential as a source of readily available natural (S)-(+)-α-phellandrene.
Assuntos
Antibacterianos/farmacologia , Burseraceae/química , Óleos Voláteis/farmacologia , Resinas Vegetais/química , Antibacterianos/química , Cromatografia Gasosa/métodos , Escherichia coli/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Óleos Voláteis/química , Staphylococcus aureus/efeitos dos fármacosRESUMO
The chemical composition of Tussilago farfara L. essential oil from the Saguenay-Lac-St-Jean region of Quebec, Canada was analyzed by gas chromatography-flame ionisation detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS), and the antibacterial activity of the oil was tested against Escherichia coli and Staphylococcus aureus. Forty-five (45) compounds were identified from the GC profile. The main components were 1-nonene (40.1%), α-phellandrene (26.0%) and ρ-cymene (6.6%). The essential oil demonstrated antibacterial activity against E. coli (MIC50 = 468 µg·mL-1; MIC90 = 6869 µg·mL-1) and S. aureus (MIC50 = 368 µg·mL-1; MIC90 = 773 µg·mL-1). Dodecanoic acid was found to be active against both bacteria having a MIC50 and MIC90 of 16.4 µg·mL-1 and 95 µg·mL-1, respectively for E. coli and a MIC50 and MIC90 of 9.8 µg·mL-1 and 27.3 µg·mL-1, respectively for S. aureus. In addition, 1-decene and (E)-cyclodecene were also found to be active against E. coli.
Assuntos
Antibacterianos/isolamento & purificação , Óleos Voláteis/química , Tussilago/química , Alcanos/análise , Alcanos/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Ciclodecanos/análise , Ciclodecanos/farmacologia , Monoterpenos Cicloexânicos/análise , Cimenos/análise , Escherichia coli/efeitos dos fármacos , Cromatografia Gasosa-Espectrometria de Massas , Ácidos Láuricos/análise , Ácidos Láuricos/farmacologia , Testes de Sensibilidade Microbiana , Quebeque , Staphylococcus aureus/efeitos dos fármacosRESUMO
New options are urgently needed for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. Balsacone C is a new dihydrochalcone extracted from Populus balsamifera that has been reported previously as being active against Staphylococcus aureus. Here, we evaluate the antibacterial activity of balsacone C against MRSA. Thirty-four (34) MRSA isolates were obtained from hospitalized patients; these isolates were then characterized for their resistance. Most of these MRSA (>85%) were resistant to penicillin, amoxicillin/clavulanic acid, ciprofloxacin, moxifloxacin, levofloxacin, clindamycin, erythromycin, and cefoxitin as well as being sensitive to linezolid, trimethoprim/sulfamethoxazole, rifampicin, and gentamicin. When tested against all MRSA isolates and various gram-positive bacteria, the antibacterial activity of balsacone C produced a MIC of 3-11.6 mg/mL. We observed no resistant isolates of MRSA (against balsacone C) even after 30 passages. Microscopy fluorescence showed that bacteria cell membrane integrity was compromised by low concentrations of balsacone C. Scanning electron microscope (SEM) confirmed balsacone C-provoked changes in the bacterial cell membrane and we find a dose-dependent release of DNA and proteins. This loss of cellular integrity leads to cell death and suggests a low potential for the development of spontaneous resistance.