Capacidad antioxidante y mecanismo de acción de pigmentos en organismos marinos / Antioxidant capacity and mechanism of action of pigments in marine organisms

Resumen Los organismos marinos poseen maravillosos colores que los hacen muy atractivos. Las características únicas de los compuestos sintetizados por especies de origen marino van más allá de su apariencia. Los pigmentos responsables de esos colores son capaces también de generar diversas actividades biológicas, como la capacidad antioxidante, la cual puede ocurrir a través de diversos mecanismos. Esto ha propiciado un aumento de su investigación, debido a su amplia aplicación en la biotecnología, farmacéutica, cosmética y alimentación de organismos vivos, expandiendo los estudios tanto in vitro como en ensayos in vivo. El objetivo de este trabajo fue compilar y describir diversos estudios recientes, enfocados en demostrar y elucidar los mecanismos de acción de los diferentes compuestos bioquímicos con actividad antioxidante, provenientes de algunos organismos marinos. Para ello, se utilizaron las bases de datos Scopus®, Web of Science™ y Microsoft Academic. Los pigmentos provenientes de organismos marinos representan una alternativa promisoria frente a los antioxidantes y aditivos sintéticos utilizados en la actualidad. El establecimiento y comprensión de los mecanismos de acción de los componentes pigmentados bioactivos, aislados de los organismos marinos, permitirá determinar con mayor precisión su posible aplicación en la industria.

Abstract Marine organisms have wonderful colors that make them very attractive. The unique characteristics of the compounds synthesized by species of marine origin go beyond their appearance. The pigments responsible for these colors are also capable of exerting biological activities, including the antioxidant capacity, which can be performed by different mechanisms. This has led to an increase in research attention due to their potential application in the pharmaceutical, cosmetics and food industries, and has expanded from in vitro studies to in vivo tests. The objective of this review is to compile and describe the studies aimed at establishing and elucidating the mechanisms of action of different biochemical compounds with antioxidant activities from marine species. In order to achieve that objective, the Scopus®, Web of Science™ and Microsoft Academic databases were used. Marine pigments represent a promising alternative to the antioxidants and synthetic additives used today. By establishing and understanding the mechanisms of action of the bioactive pigmented compounds isolated from marine organisms, it is possible to determine with greater precision their possible application in the industry.

Xanthommatin is Behind the Antioxidant Activity of the Skin of Dosidicus gigas.

Marine bioactive compounds have been found in very different sources and exert a very vast array of activities. Squid skin, normally considered a discard, is a source of bioactive compounds such as pigments. Recovering these compounds is a potential means of valorizing seafood byproducts. Until now, the structure and molecular properties of the bioactive pigments in jumbo squid skin (JSS) have not been established. In this study, methanol-HCl (1%) pigment extracts from JSS were fractionated by open column chromatography and grouped by thin-layer chromatography in order to isolate antioxidant pigments. Antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH●) and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS●+) radical scavenging assays and ferric reducing power (FRAP) assay. Fractions 11-34 were separated and grouped according to flow rate values (F1-F8). Fractions F1, F3, and F7 had the lowest IC50 against ABTS●+ per milligram, and fractions F3 and F7 showed the lowest IC50 in the FRAP assay. Finally, fraction F7 had the highest DPPH● scavenging activity. The chemical structure of the F7 fraction was characterized by infrared spectroscopy, 1H nuclear magnetic resonance, and electrospray ionization-mass spectrometry. One of the compounds identified in the fraction was xanthommatin (11-(3-amino-3-carboxypropanoyl)-1-hydroxy-5-oxo-5H-pyrido[3,2-a]phenoxazine-3-carboxylic acid) and their derivatives (hydro- and dihydroxanthommatin). The results show that JSS pigments contain ommochrome molecules like xanthommatin, to which the antioxidant activity can be attributed.

New icing media for quality enhancement of chilled hake (Merluccius merluccius) using a jumbo squid (Dosidicus gigas) skin extract.

BACKGROUND: An advanced strategy for chilled fish preservation, based on the inclusion in ice of an extract of jumbo squid (Dosidicus gigas) skin (JSS), is proposed. Aqueous solutions including acetic acid-ethanol extracts of JSS were tested at two different concentrations as icing media, with the effects on the quality evolution of chilled hake (Merluccius merluccius) being monitored. RESULTS: A significant inhibition (P < 0.05) of microbial activity (aerobes, psychrotrophs, Enterobacteriaceae, proteolytic bacteria; pH, trimethylamine) was obtained in hake corresponding to the icing batch including the highest JSS concentration. Additionally, fish specimens from such icing conditions showed an inhibitory effect (P < 0.05) on lipid hydrolysis development, while no effect (P > 0.05) was depicted for lipid oxidation. Sensory analysis (skin and mucus development; eyes; gills; texture; external odour; raw and cooked flesh odour; flesh taste) indicated a shelf life extension of chilled hake stored in ice including the highest JSS concentration. CONCLUSION: A profitable use of JSS, an industrial by-product during jumbo squid commercialisation, has been developed in the present work, which leads to a remarkable microbial inhibition and a significant shelf life extension of chilled hake. In agreement with previous research, ommochrome pigments (i.e. lipophilic-type compounds) would be considered responsible for this preservative effect. © 2016 Society of Chemical Industry.

Neurocysticercosis: radiologic-pathologic correlation.

Neurocysticercosis is a neurologic parasitic disease caused by the encysted larva of the tapeworm Taenia solium and is the most important parasitic disease of the human central nervous system. It is the most common cause of acquired epilepsy in endemic settings and constitutes a public health challenge for most of the developing world. Nowadays, however, as a result of globalization, neurocysticercosis is being seen more frequently in developed countries as well. Neurocysticercosis is acquired through fecal-oral contamination, and the disease course is complex, with two intermediate hosts (ie, pigs and humans) and a definitive host (humans). Traditionally, it has been classified into active and nonactive forms according to disease location. Radiologists must be aware of its imaging appearance, which is quite variable, as is the differential diagnosis. Imaging findings depend on several factors, including the stage of the life cycle of T solium at presentation; the number and location (ie, subarachnoid, cisternal, or intraventricular) of parasites; and associated complications such as vascular involvement (ie, arteritis with or without infarction), inflammatory response (ie, edema, gliosis, or arachnoiditis), and, in ventricular forms, degree of obstruction. Thus, the diagnostic approach, management, and prognosis for neurocysticercosis differ widely depending on the type of infection.

Prospective study of single and multiple lacunar infarcts using magnetic resonance imaging: risk factors, recurrence, and outcome in 175 consecutive cases.

BACKGROUND AND PURPOSE: We investigated whether lacunar infarct (LI) patients with >1 lacune have different vascular risk factors, a different prognosis, and poorer functional outcome than those with a single lacune. METHODS: The study included 175 first-ever LI patients. The group was divided according to the presence of multiple (n=136) or single (n=39) LI. The association of single or multiple LI with the principal vascular risk factors, leukoaraiosis, outcome, and recurrence was investigated with logistic regression models that included age, sex, and cardiac disease. RESULTS: No significant differences were found between single and multiple LI with respect to age, hypertension, hyperlipidemia, smoking, and heavy alcohol drinking. Diabetes mellitus (odds ratio [OR], 2.43; 95% CI, 1.09 to 5.4), high levels of hematocrit (>0.47) (OR, 1.09; 95% CI, 1.04 to 1.21), and leukoaraiosis (OR, 3.58; 95% CI, 1.77 to 7.51) were significantly related to multiple but not to single LI. Stroke recurrence rate was 7.7% in patients with single LI and 24.3% in the multiple LI group (OR, 3.84; 95% CI, 1.1 to 13.3). During a median follow-up of 12 months (range, 6 to 156 months), 94% of the single LI patients and 77.2% of the multiple LI patients had favorable outcomes (Rankin Scale score 0 to 2) (OR, 5.4; 95% CI, 1.25 to 23.9). CONCLUSIONS: Diabetes mellitus, leukoaraiosis, and high levels of hematocrit are important risk factors in patients with >1 LI. The presence of multiple LI may be an important prognostic indicator not only for functional recovery but also for a higher rate of recurrence.