Formulation of Garlic Essential Oil-assisted Silver Nanoparticles and Mechanistic Evaluation of their Antimicrobial Activity against a Spectrum of Pathogenic Microorganisms.

BACKGROUND: The synthesis of nanoparticles using the principle of green chemistry has achieved huge potential in nanomedicine. Here, we report the synthesis of silver nanoparticles (Ag- NPs) employing garlic essential oil (GEO) due to wide applications of GEO in the biomedical and pharmaceutical industry. OBJECTIVE: This study aimed to synthesise garlic essential oil-assisted silver nanoparticles and present their antimicrobial and antibiofilm activities with mechanistic assessment. METHOD: Initially, the formulation of AgNPs was confirmed using different optical techniques, such as XRD, FT-IR, DLS, zeta potential, SEM, and EDX analysis, which confirmed the formulation of well-dispersed, stable, and spherical AgNPs. The antimicrobial and antibiofilm activity of GEO-assisted AgNPs was evaluated against a spectrum of pathogenic microorganisms, such as Gram-positive (S. aureus and B. subtilis) and Gram-negative (E. coli and P. aeruginosa) bacteria. RESULTS: The AgNPs exhibited remarkable antimicrobial and anti-biofilm activity against all tested strains. The mechanism behind the antimicrobial activity of AgNPs was explored by estimating the amount of reactive oxygen species (ROS) generated due to the interaction of AgNP with bacterial cells and observing the morphological changes of bacteria upon AgNP interaction. CONCLUSION: The findings of this study concluded that ROS generation due to the interaction of AgNPs with bacterial cells put stress on bacterial membranes, altering the morphology of bacteria, exhibiting remarkable antimicrobial activity, and preventing biofilm formation.

Industrial Distillation Fractions of Garlic Essential Oil, Design, Synthesis, and Antifungal Activity Evaluation of Aliphatic Substituted Trisulfide Derivatives.

Garlic oil has a wide range of biological activities, and its broad-spectrum activity against phytopathogenic fungi still has the potential to be explored. In this study, enzymatic treatment of garlic resulted in an increase of approximately 50 % in the yield of essential oil, a feasible GC-MS analytical program for garlic oil was provided. Vacuum fractionation of the volatile oil and determination of its inhibitory activity against 10 fungi demonstrated that garlic oil has good antifungal activity. The antifungal activity levels were ranked as diallyl trisulfide (S-3)>diallyl disulfide (S-2)>diallyl monosulfide (S-1), with an EC50 value of S-3 against Botrytis cinerea reached 8.16 mg/L. Following the structural modification of compound S-3, a series of derivatives, including compounds S-4~7, were synthesized and screened for their antifungal activity. The findings unequivocally demonstrated that the compound dimethyl trisulfide (S-4) exhibited exceptional antifungal activity. The EC50 of S-4 against Sclerotinia sclerotiorum reached 6.83 mg/L. SEM, In vivo experiments, and changes in mycelial nucleic acids, soluble proteins and soluble sugar leakage further confirmed its antifungal activity. The study indicated that the trisulfide bond structure was the key to good antifungal activity, which can be developed into a new type of green plant-derived fungicide for plant protection.

High speed homogenization assisted encapsulation of synergistic essential oils formulation: Characterization, in vitro release study, safety profile, and efficacy towards mitigation of aflatoxin B1 induced deterioration in rice samples.

Application of essential oils to mitigate aflatoxin B1 (AFB1) contamination in food is a current research hotspot; however, their direct incorporation may cause toxic effects, and changes in food organoleptic properties. This work aimed to synthesize novel synergistic formulation of Pinus roxburghii, Juniperus communis, and Cupressus sempervirens essential oils by mixture design assay (PJC) and encapsulation of PJC formulation into chitosan nanocomposite (Nm-PJC) with an aim to protect stored rice (Oryza sativa L., prime staple food) against fungi and AFB1 mediated loss of valuable minerals, macronutrients, and fatty acids. Nm-PJC was characterized through DLS, SEM, FTIR, and XRD analyses, along with controlled delivery from chitosan nanobiopolymer. Encapsulation of synergistic formulation into chitosan-nanomatrix improved antifungal (4.0 µL/mL), antiaflatoxigenic (3.5 µL/mL), and antioxidant activities (P < 0.05). Impairment in ergosterol and methylglyoxal biosynthesis along with in-silico-homology-modeling of major components with Ver-1 and Omt-A proteins advocated chemico-molecular interaction responsible for fungal growth inhibition and AFB1 secretion. In addition, in-situ efficacy against lipid-peroxidation, fatty acid biodeterioration, and preservation of minerals, macronutrients without affecting organoleptic attributes in rice and high mammalian safety profile (9874.23 µL/kg) suggested practical application of synergistic nanoformulation as innovative smart, and green candidate to mitigate AFB1 contamination, and shelf-life extension of stored food products.

Preparation and Antibacterial Activity of Thermo-Responsive Nanohydrogels from Qiai Essential Oil and Pluronic F108.

Essential oils (EOs) have been used in cosmetics and food due to their antimicrobial and antiviral effects. However, the applications of EOs are compromised because of their poor aqueous solubility and high volatility. Qiai (Artemisia argyi Levl. et Van. var. argyi cv. Qiai) is a traditional Chinese herb and possesses strong antibacterial activity. Herein, we report an innovative formulation of EO as nanohydrogels, which were prepared through co-assembly of Qiai EO (QEO) and Pluronic F108 (PEG-b-PPG-b-PEG, or PF108) in aqueous solution. QEO was efficiently loaded in the PF108 micelles and formed nanohydrogels by heating the QEO/PF108 mixture solution to 37 °C, by the innate thermo-responsive property of PF108. The encapsulation efficiency and loading capacity of QEO reached 80.2% and 6.8%, respectively. QEO nanohydrogels were more stable than the free QEO with respect to volatilization. Sustained QEO release was achieved at body temperature using the QEO nanohydrogels, with the cumulative release rate reaching 95% in 35 h. In vitro antibacterial test indicated that the QEO nanohydrogels showed stronger antimicrobial activity against S. aureus and E. coli than the free QEO due to the enhanced stability and sustained-release characteristics. It has been attested that thermo-responsive QEO nanohydrogels have good potential as antibacterial cosmetics.

Essential oils loaded-chitosan nanocapsules incorporation in biodegradable starch films: A strategy to improve fruits shelf life.

Thermoplastic starch (TPS) films filled with chitosan nanocapsules (CN) containing essential oils (EO) were prepared aiming active packaging. Two different EOs were studied: Ho wood (H) and Cinnamon (C). Besides, different capsules concentrations were investigated (1, 3, and 5 wt%), and the films were evaluated by chemical structure, thermal stability, crystallinity, water vapor permeability, antimicrobial assays, and potential application for strawberry packaging. The TPS/CN-Ho wood films showed a strong interaction between chitosan-starch, mainly for 3 and 5 wt%, confirmed by XRD. The FT-Raman spectra of TPS/CN-Cinnamon film indicated that Cinnamon EO quickly migrated to starch films, probably due to the new crystal structure, named C-type, affecting the film's water permeability. The addition of 1 and 3 wt% CN loaded with Ho wood or Cinnamon EO to the films decreased the water permeability. 3 wt% CN was the optimum concentration to inhibit the Escherichia coli or Bacillus subtillis growth on the films, confirming their biological activity. The films' preservation properties were evaluated using strawberries, and films with 1 or 3 wt% loaded-CN could extend the strawberries' shelf life without fungi contamination. The developed TPS films can be used as active food packaging or other films for biomedical or pharmaceutical applications.

Investigation on the Epoxidation of Piperitenone, and Structure-activity Relationships of Piperitenone Oxide for Differentiation-inducing Activity.

Piperitenone oxide, a major chemical constituent of the essential oil of spearmint, Mentha spicata, induces differentiation in human colon cancer RCM-1 cells. In this study, piperitenone oxide and trans-piperitenone dioxide were prepared as racemic forms by epoxidation of piperitenone. The relative configuration between two epoxides in piperitenone dioxide was determined to be trans by 1H NMR analysis and nuclear Overhauser effect spectroscopy (NOESY) in conjunction with density functional theory (DFT) calculations. Optical resolution of (±)-piperitenone oxide by high-performance liquid chromatography (HPLC) using a chiral stationary phase (CSP) afforded both enantiomers with over 98% enantiomeric excess (ee). Evaluation of the differentiation-inducing activity of the synthetic compounds revealed that the epoxide at C-1 and C-6 in piperitenone oxide is important for the activity, and (+)-piperitenone oxide has stronger activity than (-)-piperitenone oxide. The results obtained in this study provide new information on the application of piperitenone oxide and spearmint for differentiation-inducing therapy. Furthermore, natural piperitenone oxide was isolated from M. spicata. The enantiomeric excess of the isolated natural piperitenone oxide was 66% ee. Epoxidation of piperitenone with hydrogen peroxide proceeded in a phosphate buffer under weak basic conditions to give (±)-piperitenone oxide. These results suggest that the nonenzymatic epoxidation of piperitenone, which causes a decrease in the enantiomeric excess of natural piperitenone oxide, is accompanied by an enzymatic epoxidation in the biosynthesis of piperitenone oxide.

Nano-interfacial decoration of Halloysite Nanotubes for the development of antimicrobial nanocomposites.

In recent times, incorporation of Halloysite Nanotubes (HNTs) with various antimicrobial agents as interfacial materials between these nanotubes and pathogenic microorganisms, for the development of antimicrobial nanocomposites with enhanced antimicrobial activities has gained researcher's interest. The main benefits given by HNT to these nanocomposites include enhanced thermal and mechanical stability of the antimicrobial nanocomposites and also prolong durability and release of the antimicrobial agents in a sustained manner. The exceptional structure of these aluminosilicate minerals based nanotubes (hollow tubular lumen with huge surface area) and oppositely charged surface molecules assist in attaching various molecules on both, the internal surface as well as on the outer surface of these nanotubes. Other advantages of these clay-based minerals are their biocompatibility, non-toxicity, eco-friendly nature and their natural availability with affordable price, which also contribute in selecting them as supporting material for biological applications. Therefore, these clay-based nanotubes have been recently used for developing various antimicrobial nanocomposites. In this review, various antimicrobial nanocomposites developed through incorporation of HNT with myriad antimicrobial agents such as nanoparticles, metal ions, antibiotics, essential oils, biopolymers, phenolic compounds, surfactants and food preservatives as an interface between these nanotubes and microorganisms have been discussed. These antimicrobial nanocomposites could be synthesized in different forms (powder, film, nanocapsule and adhesive) which can be applicable in various fields such as food packaging, water decontamination, waste water management, healing of wounds, antimicrobial agents for surfaces, orthopedics and for the treatment of microbial infections.

Electrospun essential oil-doped chitosan/poly(ε-caprolactone) hybrid nanofibrous mats for antimicrobial food biopackaging exploits.

Development of antimicrobial electrospun nanofibrous mats is one of the most recent trends in the field of food biopackaging. Herein, novel antimicrobial fibrous mats consisting of blend electrospun chitosan (CS)/poly(ε-caprolactone) (PCL) embedded with oregano essential oil (OEO) were fabricated via electrospinning approach and investigated. FE-SEM manifested that as-spun fibers were well-oriented with uniform diameters along their lengths, and AFM displayed the dense nature of the fibrous mats, with surface roughness in the range of 62.9-84.6 nm. The physical interactions and hydrogen bonding between CS/PCL and OEO were verified by FTIR. This novel hybrid mat demonstrated excellent mechanical strength of 14.0 MPa and achieved good water vapor barrier performance. In vitro release assay also revealed that most of plant essential oil loaded fiber mats was remained (56.4-81.7%) after 96 h, demonstrating its durability. Furthermore, the CS/OEO(5%)/PCL nanofiber mats exhibited distinctive antibacterial activity towards Gram-positive (Staphylococcus aureus, Listeria monocytogenes) and Gram-negative (Salmonella enteritidis, Escherichia coli) bacteria. This study gives insights to design new fiber-based antimicrobial nanomaterials of interest in food packaging exploits.

Synthesis of Carum Carvi essential oil nanoemulsion, the cytotoxic effect, and expression of caspase 3 gene.

Scientists are attempting to find novel methods to overcome cancers. Nanoemulsion systems as the novel drug delivery tools have been widely used in cancer therapy. In this study, the Carum Carvi oil nanoemulsions (CCONE) were prepared and its cytotoxic activity was studied on human colon cancer HT-29 cells using MTT assay. Flow cytometry and Real-time qPCR were triggered to evaluate the nanoemulsions' apoptotic properties. The results showed a significant negative association between the HT-29 cancer cell viability and CCONE doses of treatments compared with Huvec normal cells (p value < 0.001). The IC50 values were estimated 12.5 µg/ml and 50 µg/ml for HT-29 and Huvec, respectively. Moreover, we observed that increasing concentrations of nanoemulsions significantly upregulate Caspase-3 gene expression. The results showed the CCONE is an efficient novel apoptosis inducer for human colon cancer cells without any undesirable side effects. However, further in vitro and in vivo researches are required. PRACTICAL APPLICATIONS: Cancer is a complex and usually untreatable disorder. Several types of cancer therapy strategies have been applied widely to overcome cancers. Chemotherapy has been used in various types of cancers. In most cases, not only it had not been effective on cancer cells but also been distractive within normal tissues. According to results, Carum Carvi essential oil nanoemulsions have apoptotic and cytotoxic effects on colon cancer cells (HT-29). When it comes to cancer of any kind, it's important to realize that no dietary supplement can fully treat, cure, or prevent cancer. However, there are some supplements that can potentially decrease the risk of cancer. Nanoemulsions present several advantages including the ability to incorporate hydrophilic, amphiphilic, and lipophilic excipient ingredients, high physical stability, and rapid gastrointestinal digestibility. The Carum Carvi essential oil nanoemulsion can also be applied as an effective food supplement due to its potent apoptotic activity.

Interference of Seasonal Variation on the Antimicrobial and Cytotoxic Activities of the Essential Oils from the Leaves of Iryanthera polyneura in the Amazon Rain Forest.

The essential oils (EOs) obtained from the leaves of Iryanthera polyneura Ducke trees was chemically Assessed and tested for the ability of inhibiting the growth of Candida albicans, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus mutans and S. sanguinis. The oil was also tested against breast (MCF-7) and prostate (PC-3) cancer cell lines. Minimum bactericidal concentrations (MBCs) and 50 % inhibition concentrations (IC50 ) values were obtained. EOs were active against Gram-positive bacteria. Spathulenol, α-cadinol and τ-muurolol were major components of EOs. The oils showed a higher cytotoxicity against PC-3 than MCF-7 cells, although the oils were active against both cell types. Oils obtained from leaves collected in the dry season were more active against E. faecalis, S. aureus and PC-3, while the oils obtained from leaves collected in the rainy season were more active against S. mutans, S. sanguinis and MCF-7. The antibacterial and cytotoxic activities of the essential oils from the leaves of I. polyneura are related to the seasonal climate variation and are influenced by compounds that are minor components of the oils.

Isocostic Acid, a Promising Bioactive Agent from the Essential Oil of Inula viscosa (L.): Insights from Drug Likeness Properties, Molecular Docking and SAR Analysis.

The chemical composition of the essential oil (LEO) and its volatile fractions (V1 -V10 ) collected during the hydrodistillation process every 15 min from the fresh leaves of I. viscosa (L.), growing in Tunisia, were analyzed by GC-FID and GC/MS. Eighty-two compounds, representing 90.9-99.4 % of the total samples, were identified. The crude essential oil (LEO) and its fractions (V1 -V10 ) were characterized by the presence of a high amount of oxygenated sesquiterpenes (82.7-95.8 %). Isocostic acid (1) was found to be the most abundant component (37.4-83.9 %) and was isolated from the same essential oil over silica gel column chromatography and identified by spectroscopic methods (1 H, 13 C, DEPT 135 NMR and EI-MS) and by comparison with literature data. Furthermore, the fresh leaves essential oil (LEO), its volatile fractions (V1 -V10 ) as well as compound 1 were screened for their antibacterial, antityrosinase, anticholinesterase and anti-5-lipoxygenase activities. It was found that the isolated compound 1 exhibited an interesting antibacterial activity against Staphylococcus aureus ATCC 25923 (MIC=32 µg/mL) and Enterococcus faecalis ATCC 29212 (MIC=32 µg/mL) and the highest antityrosinase activity (IC50 =13.82±0.87 µg/mL). Compound 1 was also found to be able to strongly inhibit 5-lipoxygenase with an IC50 value of 59.21±0.85 µg/mL. The bioactivity and drug likeness scores of compound 1 were calculated using Molinspiration software and interpreted, and the structure-activity relationship (SAR) was discussed with the help of molecular docking analysis.

Quimiocastração com óleo essencial de Eugenia caryophyllata em cães / Canine chemical castration with Eugenia caryophyllata essential oil / Esterilización química con aceite Esencial de eugenia caryophyllata en perros

A esterilização química é uma técnica de esterilização que consiste na aplicação intratesticular de agentes esclerosantes, com o intuito de causar dano ao tecido testicular e, consequentemente, suprimir a atividade reprodutiva em animais do sexo masculino. Por ser uma técnica de rápida execução, de baixo custo e com baixos riscos de gerar complicações, vem sendo estudada como forma de esterilização em animais domésticos, especialmente pensando-se em sua utilização em larga escala. O presente estudo buscou avaliar a eficácia a médio prazo da quimiocastração com óleo essencial de cravo da índia. Doze cães adultos, sem raça definida, foram incluídos na pesquisa. Um grupo consistiu no grupo controle, o qual foi constituído de animais onde foi injetado 0,5 ml de solução fisiológica 0,9% em cada testículo, e outro, com a injeção de 0,5 mL de óleo essencial de cravo da índia em cada testículo. Foi possível observar histologicamente no grupo tratado que após 42 dias da quimiocastração houve a ocorrência de danos teciduais que geraram comprometimento da espermatogênese, o que não foi verificado no grupo controle. Apesar de o grupo tratado ter apresentado maior reação inflamatória dos testículos, as análises de cortisol e avaliação das escalas de dor permitiram constatar que não houve diferenças estatísticas entre o cortisol dos grupos controle e teste, e que a dor ocasionada pelo procedimento não atingiu um grau intenso, respectivamente. As análises bioquímicas das funções renal e hepática possibilitou verificar que, em ambos os grupos, não houve sinais de toxicidade para estes órgãos. Sendo assim, a sua utilização demonstrou-se eficaz e segura em causar supressão da atividade reprodutiva em cães machos, porém, mais estudos devem ser realizados de forma a verificar se os efeitos perduram em longo prazo.(AU)

Chemical castration is a sterilization technique consisting of intratesticular application of sclerosing agents with the intention of damaging the testicular tissue and, consequently, suppressing the reproductive activity in male animals. Since it is a fast-running, low-cost technique with low complication risks, it has been studied as a form of sterilization in pets, with special focus on a large-scale use. This study sought to evaluate the medium-term efficacy of clove essential oil as a chemical castration agent. Twelve adult dogs with no defined breed were included in the study. One group was considered the control group, which consisted of animals where 0.5 ml 0.9% saline solution was injected into each testicle. The other group was injected 0.5 ml clove essential oil in each testicle. It was possible to histologically observe in the treated group that after 42 days of the chemical sterilization there was the occurrence of tissue damages that generated spermatogenesis impairment, which was not verified in the control group. Although the treated group presented a greater inflammatory reaction of the testes, the cortisol analysis and evaluation of the pain scales showed that there were no statistical differences between the cortisol level of both groups, and that the pain caused by the procedure did not reach an intense degree, respectively. Biochemical analyzes of kidney and liver functions made it possible to verify that, in both groups, there were no signs of toxicity to these organs. Therefore, its use has been shown to be effective and safe in suppressing reproductive activity in male dogs. However, further studies should be carried out to verify if the effects persist in the long term.(AU)

La esterilización química es una técnica que consiste en la aplicación intratesticular de agentes esclerosantes, con el fin de causar daño al tejido testicular y, consecuentemente, suprimir la actividad reproductiva en animales del sexo masculino. Por ser una técnica de rápida ejecución, de bajo costo y con bajos riesgos de generar complicaciones, viene siendo estudiada como forma de esterilización en animales domésticos, especialmente pensando en su utilización a gran escala. El presente estudio buscó evaluar la eficacia a medio plazo de la esterilización química con aceite esencial del clavo de India. Doce perros adultos, sin raza definida, fueron incluidos en la investigación. Un grupo consistió en el grupo control, el cual fue constituido de animales donde se inyectó 0,5 ml de solución fisiológica 0,9% en cada testículo, y otro, con la inyección de 0,5 ml de aceite esencial del clavo de India en cada testículo. Se pudo observar histológicamente en el grupo tratado que, después de 42 días de la esterilización química hubo la ocurrencia de daños en tejidos que generaron comprometimiento de la espermatogénesis, lo que no fue verificado en el grupo control. A pesar de que el grupo tratado hubiera presentado mayor reacción inflamatoria de los testículos, los análisis de cortisol y evaluación de las escalas de dolor permitieron constatar que no hubo diferencias estadísticas entre el cortisol de los grupos control y prueba, y que el dolor ocasionado por el procedimiento no alcanzó un grado intenso, respectivamente. Los análisis bioquímicos de las funciones renal y hepática permitieron verificar que, en los grupos no hubo signos de toxicidad para estos órganos. Por lo tanto, su uso se demostró eficaz y seguro en causar supresión de la actividad reproductiva en perros machos, sin embargo, más estudios deben ser realizados para verificar si los efectos perduran a largo plazo.(AU)

Atividade in vitro do óleo essencial de Origanum vulgare L. em isolados clínicos de Aspergillus spp / In vitro activity of essential oil of Origanum vulgare L. in clinical isolates from Aspergillus spp

Aspergillus fumigatus, A. flavus e A. niger são os mais importantes agentes etiológicos da aspergilose, relevante micose aviária, com tratamento ineficaz e altas taxas de mortalidade. Em vista da importância da aspergilose, da necessidade de prospectar novos fármacos e do potencial terapêutico do óleo essencial de Origanum vulgare L. (OEO), o orégano, objetivou-se avaliar a sensibilidade in vitro de isolados clínicos de Aspergillus spp. em relação ao OEO. O óleo foi obtido por hidrodestilação em Clevenger, e a análise química realizada por cromatografia de massa (GC/MS). Observaram-se 15 diferentes compostos ativos, sendo 4-terpineol, hidrato de sabinene e timol os majoritários. Nos testes de microdiluição em caldo (Reference..., 2008), todos os isolados (n= 23) foram sensíveis ao OEO: A. fumigatus teve CIM entre 28,125mg/mL (0,1875%) e 450mg/mL (3,0%), A. flavus entre 112,5mg/mL (0,75%) e 450mg/mL, e A. niger 112,5mg/mL. CFM variou de 112,5mg/mL a 450mg/mL nos isolados de A. fumigatus, de 225mg/mL (1,5%) a 450mg/mL em A. flavus, e foi de 450mg/mL em A. niger. CIM e CFM foram idênticos em 6/14 isolados, o que demonstra que o óleo com a mesma concentração pode ter capacidade fungistática e fungicida. CIM 90 correspondeu à CIM máxima. Os resultados demonstram a atividade anti-Aspergillus do OEO, com CIM 90 de 450mg/mL (3%).(AU)

Aspergillus fumigatus, A. flavus and A. niger are the most important etiological agents of aspergillosis, a relevant avian mycosis, with innefective treatment and high mortality rates. Due the importance of aspergillosis, the necessity of prospection of new drugs and the therapeutic potential of the essential oil of Origanum vulgare L. (OEO), popularly known as oregano, aims to evaluate the in vitro sensitivity of Aspergillus spp. opposing to OEO. The oil was obtained by hydrodistillation in Clevenger, and the chemical analysis performed by mass chromatography (GC/MS). 15 different active compounds were observed, being 4-terpineol (18.4%), sabinene hydrate (15.6%) and thymol (13.6%), the majority components. In the in vitro susceptibility test, all strains showed sensitivity to OEO, MIC of Aspergillus fumigatus ranged from 28,125mg/mL (0,1875%) to 450mg/mL (3,0%), A. flavus 112,5mg/mL (0,75%) to 450mg/mL, and A. niger 112,5mg/mL. MFC ranged from 112,5mg/mL to 450mg/mL in the A. fumigatus isolates, 225mg/mL (1,5%) to 450mg/mL in A. flavus, and 450mg/mL for A. niger. The MIC and FMC values were identical in 6/14 of the isolated subjects, demonstrating that the oil with the same concentration can have fungistatic and fungicidal capacity. The results demonstrates anti-Aspergillus activities of OEO with CIM90 de 450mg/mL (3%).(AU)

In vitro and in vivo efficacy of tea tree essential oil for bacterial and yeast ear infections in dogs / Uso in vitro e in vivo do óleo essencial de Melaleuca (Melaleuca alternifolia) em otites bacterianas e por leveduras

Otitis externa is a common complaint in dogs. Bacteria and yeasts are commonly involved and may perpetuate inflammatory reactions inside the ear canal. Otoscopy, cytological examination of secretion and microbiological culture embody forms of diagnosis. Cytology also has great use in accessing treatment evolution. Therapy usually consists of cleaning ear canals and subsequent use of antibiotics or antifungal products. As some of them may cause hypersensitivity and even ototoxicity, searching for new pharmacological bases is currently necessary and justifies this study, which aimed to evaluate in vitro and in vivo efficacy of tea tree essential oil for bacterial and yeast ear infections in dogs. Twenty-eight dogs from a particular shelter in Cuiabá (Mato Grosso, Brazil), presenting clinical signs of otitis externa, were enrolled in this clinical trial. In all of them, clinical and cytological evaluations, as well as culture and susceptibility testing of the affected ears were carried out. From each dog, one ear was treated with 5% tea tree essential oil lotion and the other with standard otic formulation, according to the type of infection (bacterial, yeast or both). In vitro susceptibility testings of all ear cultures, to the same drugs used in treatment, were also carried out. Culture results showed 62.5% bacterial and fungal infection, 33.9% bacterial infection and 3.6% fungal infection, from the 56 ear samples collected. The most common microorganisms isolated were Staphylococcus intermedius, Staphylococcus aureus, Proteus mirabilis and Malassezia pachydermatis. Gram-positive bacteria were susceptible to gentamycin in 60.5% and resistant in 16.3% of the samples. Five percent tea tree essential oil formulation produced a 5mm clear zone of inhibition around the disks in one of the 63 samples evaluated. Pure (100%) tea tree essential oil formulation produced a 10mm clear zone of inhibition around the disks in four of the 63 samples evaluated, a 9mm zone in three samples, an 8mm zone in 16 samples, a 7mm zone in seven samples, a 6mm zone in two samples and there was no clear zone in 31 samples. Inhibition zones were produced by strains of Staphylococcus intermedius, Staphylococcus hyicus, Corynebacterium sp., Proteus mirabilis and Enterobacter sp. tea tree essential oil ear solution significantly induced remission of clinical signs both in bacterial and yeast ear infections. It also reduced as much Malassezia pachydermatis ear infection as the nystatin solution used in this study, while gentamycin solution showed better antibacterial effect. More studies should be conducted to evaluate in vitro diffusion properties of tea tree essential oil. Good antimicrobial spectrum and the absence of adverse reactions confirm the importance of developing a tea tree formulation as an alternative therapy for ear infections in dogs.(AU)

Otite externa é queixa frequente em cães. Bactérias e leveduras estão comumente envolvidas e podem perpetuar as reações inflamatórias dentro do canal auditivo. Dentre as formas de diagnóstico, encontram-se a otoscopia, o exame citológico da secreção e a cultura microbiológica. Citologia também tem grande utilidade no acesso à evolução do tratamento. A terapia consiste de limpeza dos canais auditivos e posterior utilização de antibióticos ou produtos antifúngicos. Como alguns antimicrobianos utilizados no tratamento podem causar hipersensibilidade e até mesmo ototoxicidade, a busca por novas bases farmacológicas justifica a existência deste estudo, que teve como objetivo avaliar in vitro e in vivo a eficiência do óleo de Melaleuca alternifolia em otites bacterianas e fúngicas de cães. Vinte e oito cães, de um abrigo particular, apresentando sinais clínicos de otite externa, foram incluídos neste estudo clínico. Todos passaram por avaliação clínica, citologia e cultura de material das orelhas afetadas. De cada animal, uma orelha foi tratada com óleo de Melaleuca 5% e a outra com formulação ótica padrão, de acordo com a afecção (bacteriana, fúngica ou mista). As culturas também foram submetidas a testes de susceptibilidade in vitro aos mesmos agentes utilizados no tratamento in vivo. Os resultados da cultura mostraram 62,5% de infecção mista (bacteriana e fúngica), 33,9% de infecção bacteriana e 3,6%, de infecção fúngica a partir das 56 orelhas. Os micro-organismos mais isolados foram Staphylococcus intermedius, Staphylococcus aureus, Proteus mirabilis e Malassezia pachydermatis. As bactérias GRAM-positivas foram sensíveis à gentamicina em 60,5% e resistentes em 16,3% das amostras. A formulação com 5% de óleo essencial de Melaleuca produziu uma zona de inibição de 5mm em torno dos discos em uma das 63 amostras avaliadas. A formulação pura (100%) do mesmo produto produziu uma zona de 10mm de inibição em quatro das 63 amostras analisadas, uma zona de 9 mm em três amostras, uma zona de 8mm em 16 amostras, uma zona de 7mm em sete amostras, uma zona de 6mm em duas amostras e não havia nenhuma zona clara em 31 amostras. Zonas de inibição foram produzidas por estirpes de Staphylococcus intermedius, Staphylococcus hyicus, Corynebacterium sp., Proteus mirabilis e Enterobacter sp. Clinicamente, a formulação com o óleo essencial de melaleuca induziu significativamente uma melhora nas manifestações, tanto nas otites bacterianas quanto nas causadas por leveduras, sendo estatisticamente semelhante ao tratamento com nistatina (nas otites por levedura), mas menos eficaz que a solução de gentamicina nas otites bacterianas. Mais estudos devem ser realizados para avaliar as propriedades de difusão in vitro do óleo essencial de melaleuca. O bom espectro antimicrobiano, a boa resposta clínica e a ausência de reações adversas confirmam a possibilidade de desenvolvimento de formulação ótica com o óleo essencial de melaleuca, como uma alternativa para a terapia de infecções do ouvido em cães.(AU)

Effect of essential oil and surfactant on the physical and antimicrobial properties of corn and wheat starch films.

The present study describes the microstructure, physical (tensile strength, elongation at break, water-vapor permeability, optical characteristics) and antimicrobial properties of biodegradable films prepared by incorporating different concentrations of lemon essential oil (LO) and surfactants (Span 80, Tween 80) into corn and wheat (CW) starch film. Results showed that the incorporation of LO provoked a decrease in water content, transparency, whiteness index (WI), water vapor permeability (WVP), solubility and tensile strength properties. Higher b*, elongation and haze values were observed in CW-LO composite films. Films with LO, especially at higher concentrations, were more effective against all tested bacteria than the control films. The films' surface and cross-section morphology was different depending on the LO contents. Compared with the CW-1LO film, the addition of surfactants significantly increased antimicrobial activity, solubility, haze, surface coarseness and porosity; remarkably decreased tensile strength and transparency. The film containing only Tween 80 showed higher b*, water content, solubility and WVP, lower WI and elongation when compared with the film containing only Span 80. These properties with some good physical and antimicrobial characteristics suggest applications for CW-LO-T/S film in a wide range of food products.

"Gold" Pressed Essential Oil: An Essay on the Volatile Fragment from Citrus Juice Industry By-Products Chemistry and Bioactivity.

Present essay explores the potentials of Citrus juice industry's by-products as alternative bioactive natural products resources. Four crude Cold Pressed Essential Oils (CPEOs), derived from orange, lemon, grapefruit, and mandarin, were studied. All CPEOs were subjected to water distillation, in order to obtain the volatile fragment, which was further fractionated with respect to distillation period in two parts, concluding to eight samples. These samples along with the four original CPEOs were assessed in relation to their phytochemical content and their repellent and larvicidal properties against Asian Tiger Mosquito. The volatiles recovery rates ranged from 74% to 88% of the CPEO. Limonene presented a significant increase in all samples ranging from 8% to 52% of the respective CPEO's content and peaked in mandarin's 2nd volatile fragment which comprised 97% of the essential oil. The refinement process presented clear impacts on both bioassays: a significant increase in larvicidal potency was observed, annotated best by the improvement by 1100% and 1300% of the grapefruit volatile fractions; repellence testing provided only one significant result, the decrease of landings by 50% as a response to mandarin's second volatile fraction. The applied methodology thus may be considered for the improvement of Citrus juice industry's by-products chemistry and bioactivity.

Drug design based on pentaerythritol tetranitrate reductase: synthesis and antibacterial activity of Pogostone derivatives.

Our previous work showed that Pogostone exerts antibacterial effects by targeting pentaerythritol tetranitrate reductase (PETNR). In order to develop derivatives of Pogostone with potent antibacterial activity, we performed molecular docking studies of Pogostone with PETNR and analyzed structure-activity relationships, which guided the structure design and the subsequent facile organocatalytic synthesis of Pogostone derivatives under mild reaction conditions. Several of the synthesized compounds showed antibacterial activity in vitro, including one compound (3h) that was highly effective against methicillin-resistant Staphylococcus aureus. These results suggest that Pogostone derivatives bearing functional groups on the side chain may be good leads for antibacterial drug development.

Hydronopylformamides: Modification of the Naturally Occurring Compound (-)-ß-Pinene to Produce Insect Repellent Candidates against Blattella germanica.

The development of a novel repellent plays an important role in the integrated control of Blattella germanica. A series of novel hydronopylformamides derivatives were synthesized from a naturally occurring compound (-)-ß-pinene. The structures of these hydronopylformamides derivatives were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (¹H-NMR and 13C-NMR), and electron impact mass spectrometry (EI-MS). Repellency of these hydronopylformamides derivatives against Blattella germanica was evaluated by the using petri dish arena method. The results showed that four derivatives (compounds 8a, 8b, 8c and 8e) exhibited repellency against Blattella germanica at a concentration of 20 mg/mL. Compound 8a was the most active compound among these derivatives, where the repelling ratios of compound 8a against Blattella germanica were 66.10%, 50.46%, 48.26%, at concentrations of 20 mg/mL, 10 mg/mL, and 5 mg/mL, respectively. In addition, compound 8a showed better repellency than the traditional insect repellent N, N-diethyl-3-methylbenzamide (DEET), which indicated that compound 8a had a good application prospect in the prevention of Blattella germanica. This research hopes to promote the value-added utilization of (-)-ß-pinene and the development of novel German cockroach repellents.

Synthesis of pogostone by one-step.

Pogostone, isolated from Pogostemon cablin, has many biological activities such as potential antibacterial, anticandida, and antifungal. Traditional extraction leads to low output of PO about 17.6 mg/kg from Herba Pogostemonis. The previous literature had reported a synthetic study and the yield had reached 4.48% with strictly controlled reaction conditions. The two methods above cannot meet the large demand of PO; we report a new synthesis method. 4-hydroxy-6-methyl-2-pyrone (1) was added in toluene, with the existence of acylation catalyst 4-dimethylaminopyridine (DMAP), 4-methylvaleric acid (2), and condensing agent dicyclohexylcarbodiimide (DCC), PO was synthesized after the combination of 3-carbon of (1) with 1-OH of (2) in the acylation reaction. The purity had reached 98%, determined by HPLC. The structure was confirmed by spectroscopic methods including infrared, electron ionization mass spectrometry, and nuclear magnetic resonance spectroscopy. PO was totally synthesized in one step including cyclization, with total yield of 27.2%.

Essential oils of Cunila galioides and Origanum majorana as anesthetics for Rhamdia quelen: efficacy and effects on ventilation and ionoregulation

This study evaluated anesthetic efficacy and possible effects of the essential oils (EOs) of Cunila galioides (EOC) and Origanum majorana (EOO) on ventilatory rate (VR) and ionoregulation in Rhamdia quelen. In the anesthesia assessments, 50, 100, 200 and 300 μL L-1 EOC and 50, 100, 200, 300, 400 and 500 μL L-1 EOO were tested, and time for induction to sedation and anesthesia stages, as well as recovery, were taken. A second trial employed lower concentrations of both EOs, 10, 25, 50 and 100 μL L-1, in order to verify VR and Na+, K+ and Cl- whole body net fluxes. Sedation was achieved with both oils at 100 µL L-1, and anesthesia at ≥ 200 µL L-1. There was no significant difference between control and EO-treated groups regarding VR, but all fish subjected to 100 µL L-1 EOC died within 2 h of exposure. Overall, ionic loss declined in the presence of the EOs. The EOC at 200 - 300 μL L-1 and EOO at 400 - 500 μL L-1 present the potential to promote fast anesthesia in R. quelen.(AU)

No presente estudo foi avaliada a eficácia da anestesia e possíveis efeitos dos óleos essenciais (EOs) de Cunila galioides (EOC) e Origanum majorana (EOO) sobre a taxa ventilatória (VR) e regulação iônica em Rhamdia quelen. Nas avaliações de anestesia, as concentrações de 50, 100, 200 e 300 μL L-1 EOC e 50, 100, 200, 300, 400 e 500 μL L-1 EOO foram testadas, e os tempos para a indução às fases de sedação e de anestesia, assim como recuperação, foram mensurados. Um segundo ensaio empregou concentrações mais baixas de ambos EOs: 10, 25, 50 e 100 μL L-1 a fim de verificar a VR e o fluxo líquido corporal dos íons Na+, K+ and Cl- . A sedação foi alcançada para ambos os óleos em 100 μL L-1, e a anestesia em concentrações ≥ 200 µL L-1. Não houve diferença significativa entre o controle e grupos tratados com EOs em relação a VR, mas todos os peixes submetidos a 100 µL L-1 do EOC morreram dentro de 2 h de exposição. No geral, a perda iônica declinou na presença dos EOs. O EOC em 200 - 300 μL L-1 e o EOO em 400 - 500 μL L-1 apresentam potencial para anestesia rápida em R. quelen.(AU)