Antioxidant activity of mojabanchromanol, a novel chromene, isolated from brown alga Sargassum siliquastrum.

Silica gel chromatography HPLC, El-Mass, and NMR analyses were performed in order to determine the structure obtained from the separation and refinement of the main components of an ethanol extraction of Sargassum siliquastrum, which indicated its antioxidant activity An ethanol extraction of Sargassum siliquastrum demonstrated the strongest antioxidant activities of ethyl acetate when isolated by silica gel chromatography This amounts to 84.9 +/- 1.2% of its 0.5 mg ml(-1) concentration. The thiobarbituric acid reactive substances (TBARS) measurements from 3 isolations of an HPLC separation of ethyl acetate showed that the antioxidant activity of peak 2 was the most dominant at 84.08% in a 0.5 mg ml(-1) concentration. Peak 2 was verified as a type of chromene through El-Mass and NMR analysis. Its metal sealing characteristic was low while its characteristic of TBARS and DPPH erasure indicated similar or higher levels of metal sealing characteristic. The NMR spectroscopic data was used to elucidate the structure of this new compound, which showed strong antioxidant activity in the assay.

Efecto de dietas con aceites de palma, girasol o pescado: sobre la susceptibilidad a la oxidación de las lipoproteínas LDL-HDL del plasma de la rata / Effect of diets with oil palm sunflower or fish: on the oxidation of LDL-HDL lipoproteins of the rat plasma

Las modificaciones oxidativas de las lipoproteínas del plasma desempeñan un papel causal e importante en el inicio y progresión de la aterosclerosis. Los estudios in vitro indican que la velocidad y extensión de la oxidación de la LDL y HDL está influenciada por su composición de ácidos grasos. En el presente estudio se evaluó el efecto del consumo por 60 días de una dieta purificada al 10% (p/p) en los aceites de palma, girasol o pescado sobre la susceptibilidad de oxidación in vitro de las fracciones conjuntas de las lipoproteínas LDL y HDL del plasma de ratas machos Sprague Dawley. Utilizamos dos métodos para la evaluación: La determinación de sustancias reactivas con el ácido tíobarbitúrico (SRTBA) propuesto por Kosugi et al y el de determinación de peróxidos descrito por El-Saadani. Se encontró por ambos métodos que existe una diferencia estadísticamente significativa (p < 0,05) entre la susceptibilidad de oxidación de las fracciones LDL + HDL de los tres grupos. El mayor grado de oxidación se observó para el grupo suplementado con aceite de pescado seguido de los grupos de girasol y palma. Esto sugiere que la incorporación de ácidos grasos monoinsaturados (oleico) en la dieta en lugar de poliinsaturados, protege las LDL + HDL de las modificaciones oxidativas al reducirse la concentración de AGPI disponibles para la peroxidación.

Oxidative modifications of lipoproteins of the plasma play a causal and important role in the beginning and progression of the atherosclerosis. Studies in vitro indicate that the speed and extension of the oxidation of LDL and HDL are influenced by its fatty acid composition. In the present study the effect of the consumption for 60 days of a diet purified containing 10 % of either palm, sunflower or fish oil were evaluated on the susceptibility to in vitro oxidation of LDL+HDL lipoproteins from the plasma of male Sprague Dawley rats. For this evaluation we performed two methods: determination of reactive substances with tiobarbituric acid (SRTBA) proposed for Kosugi et al, and the peroxides as described by Al-Saadani. It was found, by both methods, that a statistically significant difference (p < 0, 05) existed between the susceptibility to oxidation of LDL and HDL fractions for the three dietary groups. The greatest degree of oxidation was observed for the group supplemented with fish oil followed by groups of sunflower and palm. This suggests that the incorporation of monounsaturated fatty acids (oleic) in the diet instead of polyunsaturated protects the oxidative modification of LDL and HDL by reducing the concentration of PUFA available for peroxidation.