Preliminary Studies on the Effect of Simulated Digestion on the Antioxidant Activity of Monoterpenes.

One of several possible ways of predicting substance bioactivity under in vivo conditions is through simulated studies based on conditions comparable to those within the organism. Having regards to pH and digestive enzymes, such an approach is through simulated digestion. Simulated studies allow gaining an understanding of physiological conditions and a prediction of compound behavior. The presented studies are based on simulated digestion (SD) to which selected monoterpenes (γ-terpinene, α-terpinene, α-phellandrene, carvone, menthone, isopulegol, α-pinene, β-pinene, terpinene-4-ol, linalool, eucalyptol, p-cymene, citral, citronellal) have been subjected. The procedure included changes pH (2.0 and 8.5) and digestive enzymes (pepsine in gastric stage and pancreatin in duodenal stage) to better understand what goes on within the gastro-intestinal tract. The changes were observed for gastric and duodenal stages, as well as for two phases: oil and water. Obtained results revealed both positive and negative influence of gastrointestinal conditions on monoterpenes antioxidant activity. However, positive impact prevailed (γ-terpinene, citral, eucalyptol, isopulegol, α-pinene). The differentiation in activity can be explained by solubility in oil/water phases and the biotransformation of studied compounds.