Conclusions

 

The antioxidant properties of ascorbic acid and of its lipophilic derivatives have been the object of several papers.

Vitamin C is a very versatile molecule, in fact it is quite easy to synthesize a wide variety of different hydrophobic compounds that possess the vitamin C ring as the polar head group, and one or more side chains. These molecules behave as surfactants in aqueous dispersions, and form supramolecular aggregates such as micelles, vesicles, or spreading monolayers, depending on their structure. Vitamin C is well soluble in water, but is very poorly soluble in hydrocarbons and fats, on the other hand its amphiphilic derivatives can be easily dissolved both in water and in organic phases, and if one considers that the antioxidant activity of vitamin C and of its derivatives is practically the same, the importance of producing large amounts of hydrophobic ascorbic acid-based chemicals is evident, especially for all those cases in which one wants to remove or reduce the damaging effect of radicals such as in certain diseases and in the conservation of food, drugs, or cosmetics, by exploiting the antioxidant activity of the ascorbic acid family.

On the other hand it must be kept in mind that ascorbic acid can also act as a prooxidant, especially in the presence of even very small amounts of transition metals such as iron and copper, being at the origin of different dangerous radical reactions.

In spite of the importance of such issue, the literature data are not completely clear, and further work is strongly needed, mainly for two reasons.

Apparently not all the experimental findings that have been obtained by studying in vitro systems have been confirmed by in vivo investigations.

Secondly, there are suspects that ascorbic acid can both act as a strong, efficient, and cheap antioxidant agent on one level, and at the same time behave as a radical promoter on a different level, and produce dangerous species in living systems.

With such premises, the synthesis of lipophilic ascorbic acid derivatives is very important, in fact the supramolecular self-assembled aggregates that they produce in aqueous media can be used as realistic models for cellular membranes, and upon proper modifications they can perform some of the functional activities typical of the real cells, or mimic the biological cellular units in their response to radicals and radical scavengers.

Since this issue is evidently related to the diagnosis and possible cure of several severe health problems, deeper accurate studies need to be undertaken in order to better elucidate:

  • the activity of vitamin C and its derivatives in vitro
  • the biological antioxidant and prooxidant performances of ascorbic acid and its derivatives in vivo
  • the effective relationship between vitamin C administration and different effects and responses in the body.


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