Coffee with cinnamon – Impact of phytochemicals interactions on antioxidant and anti-inflammatory in vitro activity

• Isobolographic analysis and interaction factor methods were applied to interaction determination.
• Nutraceutical potential of coffee may vary due to interactions of active compounds.
• Digestion in vitro affects the type of interaction between phenolic compounds.
• Food matrix affects the activity changes observed during the simulated digestion.

This paper evaluates the potential bioaccessibility and interactions between antiradical and anti-inflammatory compounds from coffee and cinnamon. Results obtained for whole plant material extracts were compared with those for chlorogenic and cinnamic acids (the main bioactive constituents of the study material). All samples, coffee, cinnamon and a mixture of the two showed abilities to scavenge free radicals and to inhibit lipoxygenase (LOX) activity. Both activities increased after simulated gastrointestinal digestion. In the mixture antiradical phytochemicals acted antagonistically – isoboles adopted the convex form. The same interactions were determined for chemical standards. The water-extractable LOX inhibitors acted synergistically – the isobole curve was “concave”. The same type of interaction was determined for standard compounds. Interestingly, after digestion in vitro a slight antagonism in the action of LOX inhibitors was observed. The results show that the food matrix and/or its changes during digestion may play an important role in creating the biological properties.