Antioxidant and surfactant: two in one compound

The CSIC has patented compounds derived from commercial alkyl gallates antioxidants (E310, E311 and E312, used as food additives) which, in addition to keep similar antioxidant activity, have surfactant properties comparable to commercial non-ionic surfactants. These compounds could be used to develop cosmetic, personal care products, food, agrochemical, fuel, and pharmaceutical products.

These gallic acid derivatives are useful as antioxidants and surfactants, especially effective because micelles are generated.Alkyl Gallates, esters derived from the natural product gallic acid, are phenolic compounds with high antioxidant activity. The antioxidants propyl gallate (E310), octyl gallate (E311) and dodecyl gallate (E312) are industrially synthesized to be ordinarily used as food additives.

Researchers at the CSIC have synthesized a series of compounds derived from alkyl gallates which preserve the antioxidant activity of these, and besides, show surfactant properties. This double feature makes them particularly effective antioxidants in emulsions and liposomes because thanks to their location outside the micelles (oil-water interface) they act as an antioxidant shield for the oil.

In order to provide surfactant activity to the alkyl gallates, a sugar moiety is introduced by synthetic chemistry in their scaffolds. The carbohydrate is attached to one of the three phenolic hydroxyl groups, which makes more hydrophilic the polar head of these molecules. Different alkyl chain length of gallates (hydrophobic tails) can be used in order to modulate the amphiphilic nature of these compounds, and therefore, their surfactant properties.

The surfactant activity has been confirmed by surface tension measurements. The antioxidant efficiency has been measured using the DPPH test, the FRAP test, and using an emulsion model based on fish oil.

These gallic acid derivatives are useful as antioxidants and surfactants, especially effective because micelles are generated. Their main advantages are:

•    Surfactant and antioxidant action is presented in only one compound. There are no similar products on the market.

•    The surfactant efficiency is similar to the others commercial non-ionic surfactants (such as Brij 30® or Tween 20®).

•    The antioxidant capacity is slightly lower than the one presented by some gallates (precursors) which are used as food antioxidants (E310, E-311, E312)), but it is higher than the capacity of other excellent antioxidants like hydroxytyrosol (olive oil antioxidant compound).

•    These antioxidants are particularly suitable for emulsions. In these conditions they are more effective than other compounds with higher antioxidant activity.

•    The structure of these compounds protects its antioxidant capacity in biological media, so the antioxidant action can be longer effective.

•    The synthesis consists only of four reaction steps and shows remarkable yields.


José Ramón Domínguez Solis
Deputy Vice-Presidency for Knowledge Transfer
Tel.: (+34) 954232349 ext 158
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