The potential of hydroxytyrosol fatty acid esters to enhance oral bioavailabilities of hydroxytyrosol and fatty acids: Continuous and slow-release ability in small intestine and blood
models indicated that hydroxytyrosol fatty acid esters (HTy-Es) could be hydrolyzed by pancreatic lipase to slow-release of free fatty acids (FAs) and HTy. Meanwhile, the HTy-Es, the liberated FAs and the HTy could cross the membrane and were transported into blood circulation. HTy-Es were further hydrolyzed by carboxylesterase in in vitro rat plasma hydrolysis model, which also showed slow-release of
Enzyme catalysis: Layer-by-layer functionalized lignin nanoparticles acts as a sustainable platform in the lipase M and tyrosinase cascade synthesis of bioactive lipophilic hydroxytyrosol esters from tyrosol and long side-chain carboxylic acids under organic solvent conditions.
Synthesis of Bioactive Hydroxytyrosol Esters via Multienzyme Cascade on Electroactive Melanin Lignin Nanoparticles: A One‐Pot Approach without Extra Reducing Agents
A one‐pot strategy for the synthesis of bioactive hydroxytyrosol esters from tyrosol and lipophilic carboxylic acids has been developedviamultienzyme cascade immobilized on electroactive melanin lignin nanoparticles. The novel catalyst involved the co‐immobilization of lipase and tyrosinase on the polyphenolic support and was operative in the presence of sustainable 2‐methyltetrahydrofuran as organic reaction solvent. The system did not require the use of extra reducing agents for the selective synthesis of catechols. Optoelectronic and electrochemical studies suggested the role played by melanin lignin nanoparticles in the regeneration of the active site of tyrosinase from unproductivemet‐form to reversibledeoxy/oxy‐form. This effect improved the overall activity of tyrosinase in the multienzyme cascade favouring the reduction of undesired quinones to corresponding catechols.
Effect of Lipophilization of Hydroxytyrosol on Its Antioxidant Activity in Fish Oils and Fish Oil-in-Water Emulsions
作者:I. Medina、S. Lois、D. Alcántara、R. Lucas、J. C. Morales
DOI:10.1021/jf9023867
日期:2009.10.28
The effect of lipophilization of the antioxidant efficiency of hydroxytyrosol on fish oil enriched systems was studied. Hydroxytyrosol fatty acid esters with increasing size of the alkyl chain and different lipophilicity were tested in bulk fish oils and fish oil-in-water emulsions. Results showed a significant antioxidant activity of hydroxytyrosol esters in both systems especially in emulsions. The introduction of a lipophilic chain decreased the antioxidant effectiveness of hydroxytyrosol in homogeneous systems as fish oils. In emulsion systems, the presence of a short-medium lipophilic chain (acetate, butyrate or octanoate) improved The antioxidant efficiency of hydroxytyrosol favoring the physical location of the antioxidant in the interface, but longer alkyl chain (laurate) maintained or even decreased their antioxidant activity. A maximum of antioxidant efficiency seems to appear when the chain length of the hydroxytyrosol derivative is that of eight carbons which is probably associated with a preferential location of the diorthophenolic moiety in the right geometry. These results are of high importance for the optimum design of effective antioxidants for omega 3 enriched foods, which are very susceptible to suffer oxidation and, then, rancidity.
Surface-Active Properties of Lipophilic Antioxidants Tyrosol and Hydroxytyrosol Fatty Acid Esters: A Potential Explanation for the Nonlinear Hypothesis of the Antioxidant Activity in Oil-in-Water Emulsions
作者:Ricardo Lucas、Francisco Comelles、David Alcántara、Olivia S. Maldonado、Melanie Curcuroze、Jose L. Parra、Juan C. Morales
DOI:10.1021/jf1009928
日期:2010.7.14
Our group has recently observed a nonlinear tendency in antioxidant capacity of different hydroxytyrosol fatty acid esters in fish oil-in-water emulsions, where a maximum of antioxidant efficiency appeared for hydroxytyrosol octanoate. These results appear to disagree with the antioxidant polar paradox. Because the physical location of the antioxidants in an oil water interface has been postulated as an important factor in explaining this behavior, we have prepared a series of tyrosol and hydroxytyrosol fatty acid esters with different chain length and studied their surface-active properties in water, because these physicochemical parameters could be directly related to the preferential placement at the interface. We have found that tyrosol and hydroxytyrosol fatty acid esters are relevant surfactants when the right hydrophilic-lipophilic balance (HLB) is attained and, in some cases, as efficient as emulsifiers commonly used in industry, such as Brij 30 or Tween 20. Moreover, a nonlinear dependency of surfactant effectiveness is observed with the increase in chain length of the lipophilic antioxidants. This tendency seems to fit quite well with the reported antioxidant activity in emulsions, and the best antioxidant of the series (hydroxytyrosol octanoate) is also a very effective surfactant. This potential explanation of the nonlinear hypothesis will help in the rational design of antioxidants used in oil-in-water emulsions.