RESUMO
This work aimed to evaluate the effects of 4 selected essential oils on planktonic cells and microbial biofilms of the Staphylococcus aureus strain (MRSA ATCC 33591). The antibacterial activities of the four essential oils Geranium (Pelargonium graveolens), PgEO, Tea Tree (Melaleuca alternifolia) MaEO, Lemon peel (Citrus limon) ClEO and Peppermint (Mentha piperita) MpEO had MICs ranging from 1.56 to 12.5 µl/ml. The evaluation of the antibiofilm activities of the 4 EOs revealed that they had antiadhesive activities against S. aureus MRSA biofilms; the activity reached 60% (the EO of MpEO peppermint at a concentration of 3.12 µl/ml), and the eradication activity was 80% (the EO of PgEO and MpEO at 3.12 µl/ml). The antibiofilm activity of S. aureus has been explained by the binding of several essential oil bioactive molecules to the SarA protein, the main target protein involved in biofilm formation. The synthesis of the virulence factor staphyloxanthin by S. aureus MRSA ATCC 33591 was significantly inhibited in the presence of PgEO at a concentration of MIC/2. This inhibition was explained by the binding of the main PgEO molecules (ß-citronellol and geraniol) to the CrTM protein involved in the staphyloxanthin synthesis pathway. There is evidence that these essential oils could be used as potential anti-virulents to control Staphylococcus biofilm formation.
Assuntos
Antibacterianos , Biofilmes , Staphylococcus aureus Resistente à Meticilina , Testes de Sensibilidade Microbiana , Óleos Voláteis , Óleos de Plantas , Xantofilas , Biofilmes/efeitos dos fármacos , Antibacterianos/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Óleos Voláteis/farmacologia , Xantofilas/farmacologia , Óleos de Plantas/farmacologia , Óleos de Plantas/química , Melaleuca/química , Mentha piperita/química , Pelargonium/química , Geranium/química , Citrus/químicaRESUMO
This study explores the potential of geranium essential oil as a natural solution for combating marine biofouling, addressing the environmental concerns associated with commercial antifouling coatings. Compounds with bactericidal activities were identified by 13Carbon nuclear magnetic resonance (13C NMR). Thermogravimetric analysis (TGA) revealed minimal impact on film thermal stability, maintaining suitability for antifouling applications. The addition of essential oil induced changes in the morphology of the film and Fourier transform infrared spectroscopy (FTIR) analysis indicated that oil remained within the film. Optical microscopy showed an increase in coating porosity after immersion in a marine environment. A total of 18 bacterial colonies were isolated, with Psychrobacter adeliensis and Shewanella algidipiscicola being the predominant biofilm-forming species. The geranium essential oil-based coating demonstrated the ability to reduce the formation of Psychrobacter adeliensis biofilms and effectively inhibit macrofouling adhesion for a duration of 11 months.
Assuntos
Incrustação Biológica , Geranium , Óleos Voláteis , Psychrobacter , Biofilmes , Incrustação Biológica/prevenção & controle , Óleos Voláteis/farmacologia , Óleos de Silicone/farmacologia , SiliconesRESUMO
Essential oils (EOs) are bioactive compounds with therapeutic potential for use as alternatives or as support to conventional treatments. However, EOs present limitations, such as sensibility to environmental factors, which can be overcome through microencapsulation. The objective of this study was to produce, by spray drying, chitosan microparticles (CMs) loaded with EO of Lemongrass (Cymbopogon flexuosus), Geranium (Pelargonium x ssp) and Copaiba (Copaifera officinalis). Physicochemical and biological characterization of these microparticles showed that CMs presented spherical morphology, had an average size range of 2-3 µm with positive zeta potential (ZP) values, and enhanced thermal stability, compared to free EO. The encapsulation efficiency (EE) ranged from 4.8-58.6%, depending on the oil's properties. In vitro EO release from CMs was determined at different pHs, with 94% release observed in acid media. All microparticles were non-hemolytic at concentrations of up to 0.1 mg·mL-1. EOs and CMs presented acetylcholinesterase (AChE) inhibition activity (IC 50 ranged from 11.92 to 28.18 µg·mL-1). Geranium and Copaiba EOs presented higher toxicity against Artemia salina, and greater inhibition of acetylcholinesterase, indicating potential bioactivity for Alzheimer's disease (AD). Our findings demonstrate that CM systems may show promise for the controlled release of these EOs.
Assuntos
Artemia/efeitos dos fármacos , Cápsulas/química , Quitosana/química , Inibidores da Colinesterase/farmacologia , Cymbopogon/química , Fabaceae/química , Óleos Voláteis/análise , Pelargonium/química , Animais , Sangue/efeitos dos fármacos , Inibidores da Colinesterase/toxicidade , Cymbopogon/toxicidade , Fabaceae/toxicidade , Hemólise , Temperatura Alta , Humanos , Concentração de Íons de Hidrogênio , Concentração Inibidora 50 , Microscopia Eletrônica de Varredura , Óleos Voláteis/química , Tamanho da Partícula , Pelargonium/toxicidade , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Abstract The essential oils (EOs) of Illicium verum and Pelargonium graveolens were evaluated for lethality, inhibition of development and residual efficacy against the flea Ctenocephalides felis felis. Their chemical composition was characterized by means of gas chromatography with a flame ionization and mass spectrometry detection. Mortality at different immature stages and among adult fleas was measured through in vitro filter paper tests at different concentrations of EOs. The chemical characterization of I. verum volatile oil showed that E-anethole (79.96%) was the major constituent, while the major compounds in P. graveolens were citronellol (29.67%) and geraniol (14.85%). Insecticidal activity against both immature and adult flea stages were observed. The EO of I. verum had insecticidal activity for approximately 18 days, while the EO activity of P. graveolens lasted for 13 days. The pulicidal activity of I. verum remained above 70% for up to 9 days, while the activity of P. graveolens was 41.7% for up to 2 days. Essential oils, especially that of I. verum, showed insecticidal activity for flea control at different life cycle stages and have potential for the development of ectoparasiticides (biopesticides) for veterinary use.
Resumo Os óleos essenciais (OE) de Illicium verum e Pelargonium graveolens foram avaliados quanto à letalidade, inibição do desenvolvimento e eficácia residual contra a pulga Ctenocephalides felis felis. Sua composição química foi caracterizada por meio de cromatografia gasosa com detector de ionização de chama e espectrometria de massas. A mortalidade entre os diferentes estágios imaturos e pulgas adultas foi avaliada por meio de testes in vitro em papel filtro, contendo diferentes concentrações de OEs. A caracterização química do óleo volátil de I. verum mostrou que o E-anetol (79,96%) foi o constituinte majoritário, enquanto os principais compostos de P. graveolens foram citronelol (29,67%) e geraniol (14,85%). Foi observada atividade inseticida contra os estágios imaturos e adulto da pulga. O OE de I. verum teve atividade inseticida por aproximadamente 18 dias, enquanto o de P. graveolens durou 13 dias. A atividade pulicida de I. verum permaneceu acima de 70% até o 9º dia, enquanto a atividade de P. graveolens foi de 41,7% até o 2º dia. Os óleos essenciais, principalmente de I. verum, apresentam atividade inseticida para o controle de pulgas em diferentes estágios do ciclo de vida e têm potencial para o desenvolvimento de ectoparasiticidas (biopesticidas) de uso veterinário.
Assuntos
Animais , Óleos Voláteis/farmacologia , Illicium/química , Pelargonium/química , Ctenocephalides/efeitos dos fármacos , Cromatografia Gasosa-Espectrometria de Massas/veterináriaRESUMO
Geranium schiedeanum has been used in traditional therapies as an antiseptic, antipyretic, and as analgesic. The present study was designed to evaluate the pretreatment with G. schiedeanum total extract (GS) and its active metabolites on stimulating the endogenous antioxidant defense system (EADS): catalase (Cat), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione reduction index (RI GSH/GSSG) in rat liver treated with a sublethal dose (6.6 mmol/Kg) of thioacetamide (TAA) in order to probe the capacity of GS and the active compounds to reduce liver injury. This was assessed by measuring aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin (BILT) in rats pretreated or not with TAA, and pretreated or not with GS and its metabolites. The results showed that GS was able to induce the production of EADS enzymes, increasing redox index GSH/GSSG at 24 and 48 h after intoxication, and both the extract and the ellagic acid exhibited a significant reduction of hepatic damage markers. Our data confirmed the hepatoprotective effect of GS and its metabolites, like ellagic acid, support the possible use of this extract in the treatment of liver injury.
RESUMO
Mosquitoes (Diptera: Culicidae) are vectors of important parasites and pathogens causing death, poverty and social disability worldwide. The overuse of synthetic insecticides to control mosquito vectors lead to resistance, adverse environmental effects and high operational costs. Therefore, the development of eco-friendly control tools is an important public health challenge. In this study, two different essential oils (EO) (geranium, Geranium maculatum, and bergamot, Citrus bergamia) loaded polymeric nanoparticle (PN) were elaborated using polyethylene glycol (PEG) and chitosan (Qx) as the polymeric matrix/coating. In addition, the mosquito larvicidal acute and residual activity of the PN was evaluated on Culex pipiens pipiens. The physicochemical characterization of PN revealed that PEG-PN had sizes <255 nm and encapsulation efficiency between 68 and 77%; Qx-PN showed sizes <535 nm and encapsulation efficiency between 22 and 38%. From the toxicological test, it was observed that Qx-PN produced higher acute and residual activity than PEG-PN. Overall, this study highlights that polymer nanoparticles containing essential oil are a promising source of eco-friendly mosquito larvicidal products.
Assuntos
Controle de Mosquitos , Nanopartículas , Polímeros , Animais , Culex , Inseticidas , Larva , Óleos VoláteisRESUMO
Infections due to microbial biofilm formation on the surface of catheters and other medical devices are constantly reported as a major cause of morbidity and mortality in patients admitted to hospitals. Furthermore, sessile cells are more resistant to phagocytosis and most antimicrobial, which complicates the treatment of such infections. Researches aimed at new antimicrobial originating mainly from plants have increased in recent years and the development of new strategies for their release is critical in combating the formation of biofilms. Geranium oil (GO) has proven antimicrobial activity. Because of this, the aim of this study was to develop nanoemulsions containing this oil (NEG) and evaluate its activity after the biofilm formation of Candida albicans, Candida tropicalis, Candida glabrata, and Candida krusei in hospital medical supplies. For quantification of the biofilm, crystal violet, total protein, and ATP-bioluminescence assays were used. The results revealed that GO and NEG showed lower MIC for C. albicans and C. tropicalis. The biofilms formed by different species of Candida on the surfaces of polyethylene and polyurethane were quantified. GO and NEG significantly inhibited the formation of biofilms in all species tested on the surfaces of polyethylene. However, NEG antibiofilm has had better activity than GO for C. albicans, C. tropicalis and C. glabrata, according to the surface potential analysis by atomic force microscopy (AFM). The analysis of the biofilm formation on the polyethylene surface by ATP-bioluminescence and CFU showed similar results. In both methods the formation of biofilm in the catheter occurred in greater quantity for C. albicans and C. tropicalis. GO did not significantly inhibit the formation of biofilms only in C. krusei, although NEG significantly increased this activity GO in all species tested when compared to the control training biofilm. The following study shows that the development of NEG may become an effective alternative to reduce the adhesion of microorganisms and prevent infections resulting from the use of some hospital medical materials.
Assuntos
Antifúngicos/farmacologia , Biofilmes/efeitos dos fármacos , Candida/efeitos dos fármacos , Equipamentos e Provisões/microbiologia , Pelargonium/química , Extratos Vegetais/farmacologia , Antifúngicos/isolamento & purificação , Candida/fisiologia , Emulsões/farmacologia , Hospitais , Testes de Sensibilidade Microbiana , Extratos Vegetais/isolamento & purificaçãoRESUMO
One of the major components of some geraniums is geraniin, described by its discoverer as crystallizable tannin, well known as an excellent antioxidant, and also found in fruits such as pomegranate. Recently, natural antioxidants have attracted great attention from consumers over the world due to their lower toxicity than synthetics. But geraniin is not a stable compound, and also is difficult to obtain, that is why in the present study we obtained acetonylgeraniin from Geranium schideanum (Gs), a stable acetone condensate of geraniin. In the present study the effect of Gs acetone-water extract was studied in reference to postnecrotic liver regeneration induced by thioacetamide (TA) in rats. Two months male rats were pretreated with daily dose of Gs extract for 4 days (300 mg/kg) and the last day also were intraperitoneally injected with TA (6.6 mmol/kg). Samples of blood were obtained from rats at 0, 24, 48, 72 and 96 h following TA intoxication. The pre-treatment with the crude extract in the model of thioacetamide-induced hepatotoxicity in rats decreased and delayed liver injury by 66% at 24 h. This result suggests that Gs extract may be used as an alternative for reduction of liver damage. On the other hand, acute toxicity study revealed that the LD50 value of the Gs extract is more than the dose 5000 mg/kg in rats, according to the Lorke method.