Inflammation is a non-specificresponse of mammalian tissues to a variety of hostile agents and helps to restore homeostasis at infected or damaged sites( 1 ) When this inflammatory response is not well regulated at intestinal level, a dysfunction characterized by overproduction of a wide spectrum of pro-inflammatory cytokines and others mediators of inflammation appears. Current anti-inflammatory treatments comprise different drugs that are frequently associated with undesirable side effects( 2 ). Consequently, in this research we try to study in depth the effect of dietary factors with antioxidant activity, specifically fruit juices enriched with pine bark extract (PBE) subjected to an in vitro gastrointestinal process( 3 ), on inflammatory intestinal process. PBE consists of a concentrate of water-soluble polyphenols and it has been demonstrated to have strong antioxidant properties.
Differentiated Caco-2 cells were used for experiment. In inflammatory conditions, two digested juices, with and without added PBE, were tested to know their anti-inflammatory effects. Trans Epithelial Electric Resistance (TEER) and levels of IL-8 and nitric oxide (NO) produced by cells were measured as indicator of inflammation level.
The results showed an important decrease in TEER when inflammation is induced, indicating a disorganization of differentiated epithelium. This effect was suppressed when digested pineapple juice enriched with PBE and digested red fruit juice, with or without PBE, was added to differentiate Caco-2 cells. Regarding IL-8 and NO levels, cells exposed to red fruit juice enriched with PBE, after digestion, showed the lowest level of both inflammatory markers; meanwhile non-enriched pineapple juice seems to have the lowest anti-inflammatory effect.
The main conclusions are that the addition of digested fruit juices added with PBE, has a significant in vitro anti-inflammatory activity; digested red fruit juice, possess a high anti-inflammatory effect, that increases when PBE is added, showing similar values of TEER, IL-8 and NO than in non-inflamed cells.