Thyme essential oils from Spain: Aromatic profile ascertained by GC-MS, and their antioxidant, anti-lipoxygenase and antimicrobial activities.

Six samples of red thyme (Thymus zygis) and two samples of winter thyme (Thymus hyemalis) essential oils (EOs) were obtained from plants cultivated in south-eastern Spain and extracted by steam distillation. Analysis by gas chromatography coupled with mass spectrometry detection provided the relative (%) and absolute (mM) concentrations. Thymol (30-54%), p-cymene (14-27%) and γ-terpinene (8-28%) were the most abundant components of T. zygis EO, while 1,8-Cineole (3-37%), p-cymene (1-29%), linalool (8-13%) and thymol (0-19%) were the most abundant components in the case of T. hyemalis EO. Enantioselective gas chromatography identified (-)-linalool, (-)-borneol and (+)-limonene as the main enantiomers. Several methods to evaluate antioxidant capacities were applied to the EOs, concluding that their activities were mainly due to thymol and linalool. The inhibition of lipoxygenase activity, mainly due to thymol, p-cymene and linalool, suggested their possible use as anti-inflammatories. The high antibacterial and antifungal activities determined for the EOs means that they can be used as natural preservatives. The results support the potential use of Thymus sp. EOs as natural food, cosmetic and pharmaceutical ingredients.

Thymus mastichina L. essential oils from Murcia (Spain): Composition and antioxidant, antienzymatic and antimicrobial bioactivities.

The compositions of essential oils (EOs) from Spanish marjoram (Thymus mastichina L.) grown in several bioclimatic zones of Murcia (SE Spain) were studied to determine their absolute and relative concentrations using gas chromatography-mass spectrometry. 1,8-Cineole and linalool were the main components, followed by α-pinene, ß-pinene and α-terpineol. (-)-Linalool, (+)-α-terpineol and (+)-α-pinene were the most abundant enantiomers. When the antioxidant capacities of T. mastichina EOs and their compounds were measured by five methods, EOs and linalool, linalyl acetate, α-terpinene and γ-terpinene, among others, showed antioxidant activities. All four T. mastichina EOs inhibited both lipoxygenase and acetylcholinesterase activities, and they might be useful for further research into inflammatory and Alzheimer diseases. Bornyl acetate and limonene showed the highest lipoxygenase inhibition and 1,8-cineole was the best acetylcholinesterase inhibitor. Moreover, these EOs inhibited the growth of Escherichia coli, Staphylococcus aureus and Candida albicans due to the contribution of their individual compounds. The results underline the potential use of these EOs in manufactured products, such as foodstuff, cosmetics and pharmaceuticals.

Composition and Antioxidant, Antienzymatic and Antimicrobial Activities of Volatile Molecules from Spanish Salvia lavandulifolia (Vahl) Essential Oils.

The current study describes the composition of Salvia lavandulifolia (Vahl) essential oils (SlEOs) obtained from plants cultivated in Murcia (Spain), as determined by gas chromatography. Relative and absolute concentrations, the enantiomeric ratios of chiral compounds and the in vitro antioxidant, antienzymatic and antimicrobial activities are described. The main components of the SlEOs were camphor, 1,8-cineole, camphene and α-pinene, and the main enantiomers were (+)-camphor and (-)-camphene. The activities against free radicals and the capacity to reduce and chelate metallic ions were measured. SlEO-3 showed the highest activity in ORAC, DPPH, ABTS and reducing power methods, while SlEO-1 exhibited the highest chelating power. The activity of lipoxygenase and acetylcholinesterase could be inhibited by all the SlEOs, being bornyl acetate and limonene the most active individual compounds against lipoxygenase and 1,8-cineole against acetylcholinesterase. SlEOs and some individual compounds inhibited Escherichia coli, Staphylococcus aureus and Candida albicans. These results increase our knowledge of SlEOs and, particularly, provide for the first time a complete characterization of SlEOs from Murcia, Spain, while proposing possible biotechnological uses for them.

Salvia officinalis L. Essential Oils from Spain: Determination of Composition, Antioxidant Capacity, Antienzymatic, and Antimicrobial Bioactivities.

Four essential oils (EOs) from Salvia officinalis L. cultivated in Spain (Murcia Province) were analyzed by gas chromatography coupled with mass spectrometry (GC/MS) to determine their relative and absolute compositions. The main components were α-thujone (22.8 - 41.7%), camphor (10.7 - 19.8%), 1,8-cineole (4.7 - 15.6%), and ß-thujone (6.1 - 15.6%). Enantioselective gas chromatography identified (-)-α-thujone and (+)-camphor as the main enantiomers in all the analyzed EOs. Furthermore, when the EOs were tested to determine their antioxidant activity against free radicals and as ferric reducing and ferrous chelating agents, all were seen to have moderate activity due to the compounds they contained, such as linalool or terpinene. Because of their known relation with inflammatory illnesses and Alzheimer's disease, respectively, the inhibition of lipoxygenase and acetylcholinesterase was studied using the EOs. Some individual compounds also inhibited these enzymes. In addition, the studied EOs were able to inhibit the growth of Escherichia coli, Staphylococcus aureus, and Candida albicans. The characterization carried out increases our awareness of the possible uses of S. officinalis EO as natural additives in food, cosmetics, and pharmaceuticals.

Origanum vulgare and Thymbra capitata Essential Oils from Spain: Determination of Aromatic Profile and Bioactivities.

Oregano (Thymbra capitata and Origanum vulgare) essential oils (EOs), cultivated and extracted in the South-East of Spain, were analysed by GC/MS to determine their composition. (E)-ß-Caryophyllene (0.5-4.9%), thymol (0.2-5.8%), p-cymene (3.8-8.2%), γ-terpinene (2.1-10.7%) and carvacrol (58.7-77.4%) were determined as the main molecules. This characterisation was completed with enantioselective gas chromatography, where (-)-(E)-ß-caryophyllene, (+)-a- pinene and (+)-ß-pinene were determined as the main enantiomers. Antioxidant activity was evaluated positively by several methods, accounting for activity against free radicals and reducing power. Important inhibitory activity on lipoxygenase (LOX) and acetylcholinesterase (AChE) was observed supporting potential anti-inflammatory, anti-Alzheimer and insecticidal activities, mainly due to carvacrol. These properties support the potential use of oregano EOs as natural cosmetic and natural pharmaceutical ingredients.

Lavandula angustifolia and Lavandula latifolia Essential Oils from Spain: Aromatic Profile and Bioactivities.

Compositions of true lavender (Lavandula angustifolia) and spike lavender (Lavandula latifolia) essential oils, cultivated and extracted in the Southeast of Spain, were determined by gas chromatography coupled with mass spectrometry detection, obtaining both relative (peak area) and absolute (using standard curves) concentrations. Linalool (37-54 %), linalyl acetate (21-36 %) and (E)-ß-caryophyllene (1-3 %) were the most abundant components for L. angustifolia. Linalool (35-51 %), eucalyptol (26-32 %), camphor (10-18 %), α-pinene (1-2 %), α-terpineol (1-2 %) and α-bisabolene (1-2 %) were the most abundant components for L. latifolia. The characterization was completed with enantioselective gas chromatography, in which the determined main molecules were (-)-linalool, (-)-linalyl acetate and (+)-camphor. (S)-(-)-camphene, (R)-(+)-limonene, (1R, 9S)-(-)-(E)-ß-caryophyllene and (1R, 4R, 6R, 10S)-(-)-caryophyllene oxide were found in this study as the predominant enantiomers in Spanish L. angustifolia. The characterised essential oils were tested for their antioxidant activity against free radicals ABTS, DPPH, ORAC, chelating, and reducing power. Inhibitory activity on lipoxygenase was observed indicating a possible anti-inflammatory activity, mainly due to linalool, camphor, p-cymene and limonene. These results can be the starting point for a future study of the potential use of L. angustifolia and L. latifolia essential oils as natural cosmetic and natural pharmaceutical ingredients for several skin diseases.

Lavandin (Lavandula × intermedia Emeric ex Loiseleur) essential oil from Spain: determination of aromatic profile by gas chromatography-mass spectrometry, antioxidant and lipoxygenase inhibitory bioactivities.

Lavandin (Lavandula × intermedia Emeric ex Loiseleur) essential oils (EOs), from Abrial, Super and Grosso cultivars, cultivated and extracted in the South East of Spain, were analysed by using GC/MS to determine their composition, in both relative (peak area) and absolute (using standard curves) concentrations. Linalool (34-47%), linalyl acetate (17-34%), camphor (4-9%) and eucalyptol (3-7%) were determined as the main molecules. This characterisation was completed with the enantioselective gas chromatography, where ( - )-linalool, (+)-camphor and ( - )-linalyl acetate were determined as the main components. Antioxidant activity was evaluated positively by several methods: activity against free radicals, chelating and reducing power, probably due to linalool and linalyl acetate. Mild inhibitory activity on lipoxygenase was observed supporting potential anti-inflammatory activity, mainly due to linalool and camphor. These properties support the potential use of L. × intermedia essential oils as natural cosmetic and natural pharmaceutical ingredient to fight several skin diseases.

Kinetic characterization of substrate-analogous inhibitors of tyrosinase.

The development of effective tyrosinase inhibitors has become increasingly important in the cosmetic, medicinal, and agricultural industries for application as antibrowning and depigmenting agents. The kinetic mechanisms of action of tyrosinase on monophenols and o-diphenols are complex, particularly in the case of monophenols because of the lag period that occurs at the beginning of the reaction. When enzyme inhibitors are studied, the problem becomes more complicated because the lag period increases, which has led to erroneous identification of the type of inhibition that many compounds exert on the monophenolase activity and the inaccurate determination of their inhibition constants. When the degrees of inhibition of an inhibitor which is analogous to tyrosinase substrates are the same for both monophenolase and diphenolase activities, this means that the inhibitor binds to the same enzymatic species and so the inhibition constants should be similar for both activities. In this study, we demonstrate this typical behavior of substrate-analogous inhibitors and propose a methodology for determining the type of inhibition and the inhibition constants for the monophenolase and diphenolase activities of the enzyme. Benzoic acid and cinnamic acid were used as inhibitors and the monophenol/o-diphenol pairs l-tyrosine/l-dopa and α-methyl-L-tyrosine/α-methyl-L-dopa as substrates.

Tyrosinase-Catalyzed Hydroxylation of 4-Hexylresorcinol, an Antibrowning and Depigmenting Agent: A Kinetic Study.

4-Hexylresorcinol (HR) is a compound used in the food and cosmetic industries as an antibrowning and lightening agent. Its use is mainly attributed to its inhibitory effect on the enzyme tyrosinase. However, the enzyme hydroxylates HR to an o-diphenol, which it then oxidizes to an o-quinone, which rapidly isomerizes to p-quinone. For tyrosinase to act in this way, the Eox form (oxy-tyrosinase) must be present in the reaction medium, which can be brought about by (a) hydrogen peroxide, (b) ascorbic acid, or (c) catalytic concentrations of o-diphenol and a reductant (NADH) to maintain it constant. This work demonstrates that HR is a substrate of tyrosinase and proposes a mechanism for its action. Its kinetic characterization provides a catalytic constant of 0.85 ± 0.04 s(-1) and a Michaelis constant of 60.31 ± 6.73 µM.

Adverse events in health and nursing care: patient safety from the standpoint of the professional's experience / Eventos adversos na saúde e os cuidados de enfermagem: a segurança dos pacientes desde a experiência do profissional / Eventos adversos en salud y cuidados de enfermería: la seguridad del paciente desde la experiencia del profesional

The aim of the present study was to acknowledge the significant aspects brought about by nurses regarding their experience of being responsible for the occurrence of health adverse events. This exploratory qualitative study employed a hermeneutic dialectic approach. The sample comprised 10 nurses who had been responsible for the occurrence of an adverse event at least once and four nursing supervisors with oversight responsibility for patients at the time the adverse events occurred. Analysis of the collected data allowed for the construction of analysis categories. Relevant issues regarding the need to empower human resources and strengthen recruitment systems were identified, with emphasis to the lack of personnel, workload, teamwork, and continuing education. Results allow for the visualization of an opportunity to put interventions into practice, aiming at contributing to a safer care system.

O estudo tem como objetivo conhecer os aspectos significativos apresentados pelas enfermeiras acerca da experiência de ter sido responsáveis por um evento adverso de saúde. Estudo qualitativo, com enfoque hermenêutico dialético. Amostra de 10 enfermeiras que tiveram ao menos uma experiência de responsabilidade perante um evento adverso e 4 supervisores de enfermagem, com responsabilidade da supervisão ao ocorrer o evento. A análise dos dados coletados permitiu construir categorias de análise relacionadas às necessidades de recursos humanos. Identificaram-se aspectos relevantes respeito à necessidade de fortalecer o sistema de recursos humanos, com dimensionamento de carga de trabalho, o trabalho em equipe, a formação do pessoal, como questões importantes para os enfermeiros. Os dados resultantes permitem enxergar um caminho para pôr em prática intervenções orientadas a colaborar com um sistema seguro de atendimento.

El estudio tuvo como objetivo conocer los aspectos significativos que surgen de las enfermeras acerca de la experiencia de haber sido responsables de un evento adverso en salud. Estudio cualitativo, con enfoque hermenéutico dialéctico. Muestra de 10 enfermeras que tuvieron al menos una experiencia de responsabilidad ante un evento adverso y cuatro supervisores de enfermería con responsabilidad de supervisión al ocurrir el evento. El análisis de los datos recogidos permitió construir categorías de análisis relacionadas con las necesidades de recursos humanos. Se identificaron aspectos relevantes respecto a la necesidad de fortalecer el sistema de recursos humanos y su selección, surgiendo la dotación de personal, la carga de trabajo, el trabajo en equipo y la formación permanente como aspectos significativos para las enfermeras. Los datos emergidos permiten visualizar un camino para poner en práctica intervenciones tendientes a colaborar con un sistema seguro de atención.

Identification of p-hydroxybenzyl alcohol, tyrosol, phloretin and its derivate phloridzin as tyrosinase substrates.

In recent years, the hydroxyalkylphenols p-hydroxybenzyl alcohol and tyrosol, and the compound phloretin and its derivate phloridzin have been described as inhibitors of the enzyme tyrosinase. When the monophenolase and the diphenolase activities of tyrosinase on its physiological substrates l-dopa and/or l-tyrosine are measured in the presence of these compounds, the rate of action of the enzyme decreases. These findings led to the identification of these compounds as inhibitors. However, these molecules show an unusual behavior as inhibitors of the enzyme indeed, in this study, we demonstrate that they are not true inhibitors but alternative substrates of the enzyme.

Aspectos significativos surgidos de la experiencia de haber sido responsable de un evento adverso en salud / Significant Aspects Arising from the Experience of Having Been Responsible for an Adverse Health Event / Aspectos significativos surgidos da experiência de ter sido responsável por um evento adverso em saúde

Objetivo: conocer los aspectos significativos para las enfermeras sobre su experiencia de haber sido responsables de un evento adverso en salud. Materiales y métodos: estudio cualitativo exploratorio, con el enfoque de la hermenéutica dialéctica. Se utilizó la técnica de análisis de contenido. Muestra constituida por doce enfermeras que tuvieron al menos una experiencia de responsabilidad ante un evento adverso con un paciente, y por cuatro supervisores de enfermería con responsabilidad de supervisión al ocurrir el evento adverso. Resultados: bajo el enfoque de la hermenéutica dialéctica, el análisis de los datos permitió construir las siguientes categorías relacionadas con la organización de salud y los recursos humanos: el contexto organizacional, el desconocimiento del proceso de notificación, la sobrecarga de trabajo, la ausencia de descanso. Conclusiones: reconocer la importancia del contexto organizacional donde se desarrollan los cuidados, el desconocimiento del proceso de notificación como aspecto por mejorar, la sobrecarga de trabajo y la ausencia de descanso del personal. Es necesario profundizar en el tema mediante investigaciones y desarrollo de intervenciones que promuevan la cultura de seguridad en la atención sanitaria, con implicaciones en la práctica y para la formación de las enfermeras.

Objective: Know what nurses regard as the significant aspects of their experience with being responsible for an adverse health event. Materials and methods: This is an exploratory qualitative study based on hermeneutics with a dialectical approach. The content analysis technique was used. The sample consisted of twelve nurses who had at least one experience with being responsible for an adverse event involving a patient, and four nursing supervisors with supervisory responsibility when an adverse event occurred. Results: Using a dialectical approach to hermeneutics, the analysis of the data allowed for construction of the following categories related to the health organization and its human resources: the organizational context, ignorance of the notification process, overwork and lack of rest. Conclusions: The importance of the organizational context in which care is provided must be recognized. Ignorance about the notification process is an aspect that requires improvement, as do situations involving overwork and lack of rest for staff members. This issue needs to be examined in greater depth through research and the development of interventions that promote a culture of safety in health care, with implications for nursing practice and training.

Objetivo: conhecer os aspectos significativos para as enfermeiras sobre sua experiência de ter sido responsáveis por um evento adverso em saúde. Materiais e métodos: estudo qualitativo exploratório, com o enfoque da hermenêutica dialética. Utilizou-se a técnica de análise de conteúdo. Amostra constituída por 12 enfermeiras que tiveram pelo menos uma experiência de responsabilidade ante um evento adverso com um paciente, e por quatro supervisores de enfermagem com responsabilidade de supervisão ao ocorrer o evento adverso. Resultados: sob o enfoque da hermenêutica dialética, a análise dos dados permitiu construir as seguintes categorias relacionadas com a organização de saúde e dos recursos humanos: o contexto organizacional, o desconhecimento do processo de notificação, o excesso de trabalho, a ausência de descanso. Conclusões: reconhecer a importância do contexto organizacional em que se desenvolvem os cuidados, o desconhecimento do processo de notificação como aspecto para melhorar, o excesso de trabalho e a ausência de descanso do pessoal. É necessário aprofundar no tema por meio de pesquisas e desenvolvimento de intervenções que promovam a cultura de segurança no atendimento sanitário, com implicações na prática e para a formação das enfermeiras.

Automated solid-phase extraction and high-performance liquid chromatographic determination of nitrosamines using post-column photolysis and tris(2,2'-bipyridyl) ruthenium(III) chemiluminescence.

A sensitive and selective post-column detection system for nitrosamines is described. The principle upon which the detector works is that UV irradiation of aqueous solutions of nitrosamines leads to cleavage of the N-NO bond. The amine generated is subsequent detected by chemiluminescence using tris(2,2'-bipyridyl) ruthenium(III), which is on-line generated by photo-oxidation of the ruthenium(II) complex in the presence of peroxydisulfate. Factors affecting the photochemical and chemiluminescent reactions were optimized to minimise their contribution to the total band-broadening. This detection system was tested for N-nitrosodimethylamine, N-nitroso-diethylamine, N-nitrosomorpholine, N-nitrosopiperidine and N-nitrosopyrrolidine, which were separated on an ODS column by isocratic reversed-phase chromatography with acetonitrile-water containing 5 mM acetate buffer at pH 4.0. A linear relationship between analyte concentration and peak area was obtained within the range 0.13-500 microg l(-1) with correlation coefficients greater than 0.9995 and detection limits of between 0.03 and 0.76 microg l(-1). Intra- and inter-day precision values of about 1.2% RSD (n = 11) and 2.5% RSD (n = 10), respectively, were obtained. The sensitivity may increase from 9 to 280 times with respect to UV detection, depending on the nitrosamine in question. An automated solid-phase extraction (SPE) system was used in conjunction with HPLC to determine nitrosamine residues in waters. Detection limits within the range 0.10-3.0 ng l(-1) were achieved for only 250 ml of sample.

Migration behaviour and separation of acetaminophen and p-aminophenol in capillary zone electrophoresis: analysis of drugs based on acetaminophen.

The migration behaviour of acetaminophen and p-aminophenol was investigated by capillary electrophoresis. The influence of different parameters (pH, nature and concentration of the running buffer and applied voltage) on the migration time, peak symmetry, efficiency and resolution was systematically investigated. The two analytes can be well separated within 4 min in a 57 cm fused-silica capillary at a separation voltage of 18 kV in a 50mM borate buffer adjusted to pH 9.5. Correlation coefficients for calibration curves in the range 0.2-200 microg ml-1 for acetaminophen and 0.3-3 microg ml-1 for p-aminophenol were higher than 0.999. The sensitivity of detection is 4.2 ng ml-1 for acetaminophen and 11.2 ng ml-1 for p-aminophenol. The method was applied to the analysis of various commercially available acetaminophen dosage forms with recoveries of 98.4-100.7%.

High-performance liquid chromatographic separation and quantification of citric, lactic, malic, oxalic and tartaric acids using a post-column photochemical reaction and chemiluminescence detection.

An HPLC method was developed for the determination of citric, lactic, malic, oxalic and tartaric acids by chemiluminescent detection following online irradiation with visible light. The organic acids were irradiated with visible light in the presence of Fe3+ and UO2(2+) to generate Fe2+, which was determined by measuring the chemiluminescence intensity in a luminol system in the absence of added oxidant. Factors affecting the photochemical and chemiluminescence reactions were optimised so that their contribution to the total band-broadening was negligible. The chromatographic separation was performed on a C18 column under isocratic reversed-phase conditions using 0.005 M H2SO4 mobile phase. The optimised method was validated with respect to linearity, precision, limits of detection and quantification, accuracy specificity and robustness. The applicability of the assay was demonstrated by analysing these compounds in real samples such as milk, fruit juices, soft drinks, wine and beer.

Development of a capillary electrophoresis method for the determination of allopurinol and its active metabolite oxypurinol.

A simple and sensitive capillary zone electrophoresis method with UV absorbance detection is described for the quantitation of allopurinol and its metabolite oxypurinol in aqueous solution. The influence of different parameters on migration times, peak symmetry, efficiency and resolution was systematically investigated; these parameters included the nature and concentration of the separation buffer, pH and applied voltage. A buffer consisting of 15 mM 2-[N-cyclohexylamino]ethanesulfonic acid (CHES) adjusted to pH 8.8 was found to provide a very efficient and stable electrophoretic system for the analysis of these compounds. The optimized method was validated with respect to precision, linearity, limits of detection and quantification, accuracy and robustness. The applicability of the assay was demonstrated by analyzing these compounds in serum and allopurinol in commercial pharmaceutical preparations.

Determination of ATP via the photochemical generation of hydrogen peroxide using flow injection luminol chemiluminescence detection.

The determination of ATP using the coupling between a photochemical reaction and a chemiluminescence reaction in a flow injection (FI) system is described. The method is based on the reaction of glucose with ATP catalyzed by hexokinase and Mg(2+) ions. The glucose that is not consumed by ATP is subsequently photooxidized using 9,10-anthraquinone-2,6-disulfonate as a sensitizer. The hydrogen peroxide produced in the photochemical reaction is monitored through the chemiluminescence reaction with luminol catalyzed by hematine. There is a linear relationship between the decrease in the chemiluminescence response and the ATP concentration at a constant concentration of glucose. Under the optimum conditions, the calibration graph is linear in the range 0.20-50.5 mg L(-1) with a throughput of 25 samples per hour and relative standard deviations between +/-0.62 and +/-1.42%. The limit of detection is 0.07 mg L(-1). The method was used for the determination of ATP in pharmaceuticals, milk, and soils.