Antioxidantes en asma: polifenoles / Antioxidants in asthma: polyphenols

Resumen EL asma es una enfermedad relacionada con estrés oxidativo. Los practicantes de la medicina alternativa han usado plantas que tienen altas concentraciones de polifenoles en el tratamiento de pacientes con asma. Este artículo revisa la administración de antioxidantes no vitamínicos en pacientes con asma, con insistencia en los polifenoles. Se realizó una búsqueda en Google Scholar y en la base de datos de RIMA de Astra Zeneca con las palabras clave y frases "asthma and flavonoids", "antioxidant therapy in asthma" "resveratrol and asthma" y "polyphenols and asthma". Se priorizó la búsqueda de estudios experimentales en modelos animales y de estudios en humanos. Existe tendencia a aceptar los efectos favorables de los polifenoles en pacientes con asma. La mayor parte de la información es más consistente en trabajos experimentales realizados en animales que cuando se comparan entre sí los pocos estudios clínicos en humanos. La interpretación de los estudios a partir de experiencias con la dieta tiene el inconveniente que el tipo y concentración de polifenoles cambia entre poblaciones y depende de regiones geográficas. Es recomendable diseñar estudios con gran cantidad de personas para evaluar la contribución de la terapia con polifenoles en sujetos con asma en profilaxis y en manejo de crisis y en terapias para el control de la enfermedad a largo plazo.

Abstract Asthma is a disease related to oxidative stress. Practitioners of alternative medicine have used plants that have high concentrations of polyphenols in the treatment of patients with asthma. This paper reviews the use of non-vitamin antioxidants in asthma, with emphasis in polyphenols. A search was made in Google Scholar and in the RIMA database of Astra Zeneca with the keywords and phrases "asthma and flavonoids", "antioxidant therapy in asthma", "resveratrol and asthma" and "polyphenols and asthma". We prioritized the search for experimental studies in animal models and studies with humans. There is a tendency to accept the favorable effects of polyphenols in asthma. Most of the information is more consistent in experimental work on animals than when comparing experiences among the few clinical studies in humans. The interpretation of studies from dietary experiences has the drawback that the type and concentration of polyphenols changes between populations and depends on geographical regions. It is advisable to design studies with a large number of people to evaluate the contribution of polyphenols in subjects with asthma in prophylaxis, crisis management and long-term disease control therapies.

[Antioxidant vitamins in asthma]. / Vitaminas antioxidantes en asma.

Asthma is a condition of unknown etiology characterized by chronic airway inflammation. Cells that mediate the inflammatory response generate reactive oxygen species that, together with other respiratory tract naturally-occurring oxidant species, produce a rupture of the redox balance, generating oxidative stress. It has been proposed that oxidative stress can be reverted by supplemental or dietary intake of antioxidant vitamins such as vitamin A, C, D and E, and this way relieve, improve or protect people with asthma. In this research, observational and placebo-controlled trials with regard to the role of antioxidant vitamins in the course of asthma, published between 1979 and 2016, were reviewed. The search engines were Google and Google Scholar, whereas consulted databases were PubMed and The Cochrane Library. There were 75 articles relevant to the subject that were found and reviewed, and it was concluded that it is not clear if the intake of supplements of these vitamins has any beneficial clinical effect on asthma control. Further controlled, longer trials are needed to elucidate the role of these nutrients in the course of asthma.

El asma es una enfermedad de etiología desconocida que cursa con inflamación crónica de las vías respiratorias. Las células que median la respuesta inflamatoria generan especies reactivas de oxígeno, que en conjunto con otras especies oxidantes presentes de manera natural en las vías aéreas ocasionan la ruptura del equilibrio redox, generando estrés oxidativo. Se ha propuesto que este puede revertirse mediante la administración de vitaminas antioxidantes como A, C, E y D y de esta forma aliviar, mejorar o proteger a las personas con asma. En esta investigación se revisaron los ensayos observacionales y controlados con placebo relativos al papel de las vitaminas antioxidantes en el curso del asma, publicados entre 1979 y 2016. Los motores de búsqueda fueron Google y Google Scholar; las bases de datos consultadas fueron PubMed y The Cochrane Library. Se encontraron y revisaron 75 artículos relevantes para el tema, de los cuales se concluyó que no está claro si la ingesta de suplementos de estas vitaminas tiene algún efecto clínico benéfico en el control del asma. Son necesarios más ensayos controlados y de mayor duración para elucidar el papel de estos nutrientes en el curso del asma.

Efficient preparation of α-ketoacetals.

The Weinreb amides 2a,b were prepared from the α,α-dimethoxyacetic acids 1c,d. A number of representative nucleophilic additions (RMgX and RLi) on 2 afforded α-ketoacetals 3a-j in 70-99% yield. These compounds represent a versatile arrangement of functional groups of significant synthetic value, as demonstrated in the synthesis of (±)-salbutamol.

Diastereoselective preparation of (R)- and (S)-2-methoxy-2-phenylpent-3-ynoic acids and their use as reliable chiral derivatizing agents.

Benzoyl-S,O-acetals 1a and 1b were used as chiral auxiliaries to achieve the diastereoselective preparation of both enantiomers of 2-methoxy-2-phenylpent-3-ynoic acids (MPPAs). The latter were condensed with several chiral secondary alcohols and some primary amines to evaluate their potential as chiral derivatizing agents (CDAs). The (1)H NMR spectra of the corresponding esters and amides showed strong consistency with the absolute configuration of the carbinol and amine moieties, whose observed ΔδL(1) and ΔδL(2) values were in the ranges of 0.1-0.4 and 0.02-0.12 ppm, respectively.