One of the most valuable activity of substances used in pharmacy is antioxidant. One of possible way to protect our cells against oxidative stress is scavenging free radicals through the action of antioxidant. It is known that the level of activity of compounds varies significantly between in vitro and in vivo conditions. Additional significant factor is digestive system along with enzymes and pH in its various parts. In order to approximate the influence of these conditions, simulated digestion was performed.

The basis of the studies was selected monoterpenes which were underwent two steps of simulated digestion: gastric and duodenal. Obtained results revealed both positive and negative influence of the process on antioxidant activity of monoterpenes. Detailed analysis revealed that the changes can be associated with biotransformation of the compounds by the reaction environment and digestive enzymes.