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Melanosis is an unsolved problem of the crustacean industry and the cause of great loss of value. This study investigates the effect of two potent, natural antioxidants isolated from olive waste (hydroxytyrosol, HT and 3,4-dihydroxyphenylglycol, DHPG) and three novel HT-derivatives containing selenium and sulfur (dihydroxytyrosyl diselenide, N-hydroxytyrosyl selenourea, and N-hydroxytyrosyl thiourea) on the prevention of melanosis in Atlantic ditch shrimp (Palaemonetes varians) during refrigerated storage. These results clearly demonstrate the positive inhibitory effect of DHPG and dihydroxytyrosyl diselenide on delaying melanosis in vivo, although this effect was not dose dependent. The effect was associated with a concomitant-inhibitory effect on tyrosinase activity in vitro. To our knowledge, so far no studies on the prevention of melanosis have been conducted on this small specie of shrimp which is available in large quantities at any time of the year at low cost. Studies with these promising compounds could then be extended to other more economically important species with a greater guarantee of success.

Purpose The objective of this study was to evaluate the capacity of modified phenols synthesized from hydroxytyrosol, a natural olive oil phenol, specifically those containing a selenium or sulphur group, to inhibit lipid peroxidation. Methods The compounds’ abilities to inhibit lipid peroxidation in liver microsomes obtained from vitamin E-deficient rats were compared to hydroxytyrosol. Results All synthetic compounds had a significant higher ability to inhibit lipid peroxidation than hydroxytyrosol. Selenium derivates displayed a higher antioxidant activity than sulphur derivatives. In addition, the antioxidant activity increased with a higher number of heteroatoms in the hydroxytyrosol molecular structure. Conclusion The study shows, for the first time, the ability of synthetic compounds, derived from the most active phenol present in olives in free form (hydroxytyrosol), and containing one or two atoms of sulphur or selenium, to inhibit the lipid peroxidation of vitamin E-deficient microsomes. The antioxidant activity of five thioureas, a disulfide, a thiol, three selenoureas, a diselenide, and a selenonium were evaluated and the results showed a higher inhibition of lipid peroxidation than the natural phenol. Selenium and sulphur derivatives of hydroxytyrosol are novel antioxidants with the potential to supplement the lack of vitamin E in the diet as natural alternatives for the prevention of diseases related to oxidative damage.

[EN] The invention relates to a method for obtaining an extract comprising hydroxytyrosol, as an acetylated product or as a mixture with 3,4 dihydroxyphenylglycol and the purification thereof, comprising at least one column chromatography of a hydroxytyrosol source such as by-products of the olive and the olive tree, using a mixture of at least two ionic resins, preferably an anionic resin with a cationic resin. Preferably, in a first phase, a phenol-rich liquid is obtained as the raw material for the extraction and purification of phenolic compounds, a second phase enables a hydroxytyrosol (HT)-enriched extract and a hydroxytyrosol with 3-4-dihydroxyphenylglycol (DHFG) mixture to be obtained, and hydroxytyrosyl acetate is produced, and, in the third phase, highly pure hydroxytyrosol, DHFG, the mixture thereof and HT acetate are obtained. Each phase comprises extraction, reaction, concentration, adsorption and desorption, using mixtures of ion exchange resins, adsorption in non-ionic resins and a polymer phenolic fraction, membranes of reverse osmosis and evaporators., [ES] Procedimiento para la obtencion de un extracto que comprende hidroxitirosol, bien como producto acetilado o como mezcla con 3,4 dihidroxifenilglicol y la purificación de todos ellos, que comprende al menos una cromatografía en columna de una fuente de hidroxitirosol como subproductos de la aceituna y del olivar, utilizando una mezcla de al menos dos resinas iónicas, preferentemente una resina aniónica con una resina catiónica. Preferentemente en una primera fase se obtiene una fuente líquida rica en fenoles como materia prima par ala extracción y purificación de compuestos fenólicos, una segunda fase permite obtener un extracto enriquecido en hidroxitirosol (HT), una mezcla hidroxitirosol con 3-4-dihidroxifenilglicol (DHFG) y se produce acetato de hidroxitirosilo, obteniendo en la tercera fase hidroxitirosol muy puro, el DHFG, su mezcla y acetato de HT. Cada fase comprende extracción, reacción, concentración, adsorción y desorción, utilizando mezclas de resinas de intercambio iónico, adsorción en resinas no iónicas y una fracción fenólica polimérica, membranas de ósmosis inversa y/o evaporadores.

Procedimiento para la obtención de extracto de hidroxitirosol, extracto mezcla de hidroxitirosol y 3,4- dihidroxifenilglicol, y extracto de acetato de hidroxitirosilo, a partir de subproductos del olivo, y su purificación. Procedimiento para la obtención de un extracto que comprende hidroxitirosol, bien como producto acetilado o como mezcla con 3,4 dihidroxifenilglicol y la purificación de todos ellos, que comprende al menos una cromatografía en columna de una fuente de hidroxitirosol como subproductos de la aceituna y del olivar, utilizando una mezcla de al menos dos resinas iónicas, preferentemente una resina aniónica con una resina catiónica. Preferentemente en una primera fase se obtiene una fuente líquida rica en fenoles como materia prima para la extracción y purificación de compuestos fenólicos, una segunda fase permite obtener un extracto enriquecido en hidroxitirosol (HT), una mezcla hidroxitirosol con 3-4- dihidroxifenilglicol (DHFG) y se produce acetato de hidroxitirosilo, obteniendo en la tercera fase hidroxitirosol muy puro, el DHFG, su mezcla, y acetato de HT. Cada fase comprende extracción, reacción, concentración, adsorción y desorción, utilizando mezclas de resinas de intercambio iónico, adsorción en resinas no iónicas y una fracción fenólica polimérica, membranas de ósmosis inversa y/o evaporadores.

[EN] The invention relates to compounds containing at least one polyphenol group and sulphur or selenium and to the uses thereof as antioxidants and free radical scavengers. In addition, the invention relates to pharmaceutical, nutraceutical and cosmetic compositions including same., [ES] La invención se refiere a compuestos que contienen al menos un grupo polifenol y azufre o selenio y sus usos como antioxidantes y captadores de radicales libres. Además, se refiere a las composiciones farmacéuticas, nutracéuticas y cosméticas que los incluyen

La invención se refiere a compuestos que contienen al menos un grupo polifenol y azufre o selenio y sus usos como antioxidantes y captadores de radicales libres. Además, se refiere a las composiciones farmacéuticas, nutracéuticas y cosméticas que los incluyen.

We report the synthesis of the hitherto unknown zwitterionic alkoxyamino cyanoboranes by reduction of O-alkyloximes with sodium cyanoborohydride; unprecedented cyanoboronated N-alkoxyformamidines were also isolated as by-products. Boronated alkoxyamines were found to be efficient cyanoborane transfer agents towards more basic amines, including aminosugars; they were also successfully transformed into neoglycoconjugates by the neoglycorandomization reaction with reducing sugars. © 2011 The Royal Society of Chemistry.