Image downloaded from pixabay.com(copyright free) Antioxidants may be described as compounds which have the capability of functioning chemically as reducing agent.They are used in pharmaceutical formulations containing easily oxidized substances in order to keep the substance in their oxidized form. The Mechanism of antioxidant action may be seen in two ways,both achieving the same net result : The active component is oxidized,the antioxidant reduces it back to its normal oxidation state. The antioxidant is oxidized in the place of active constituent. THE THEORY OF ANTIOXIDANTS  Antioxidant action is same as that involved in any oxidation-reduction or Redox reaction.For example,the usual way of examining a Redox reaction is to separate it into half-cell reaction of the oxidizing and reducing agents.Since in Redox reaction,there is a transfer of electron from one compound to other,the loss of gain of electron is used to balance the oxidation states on both sides of the half - cell react