Olive Tree Biophenols in Inflammatory Bowel Disease: When Bitter is Better

Abstract

The current therapeutic scenario for inflammatory bowel diseases (IBD) involves aminosalicylates, corticosteroids, and immunomodulators, but concerns regarding their safety profiles and high costs heavily impact their widespread use. In recent years, the beneficial effects thatbiophenols-from fruit and vegetables-have on human health have been investigated. The antioxidant and anti-inflammatory properties of phenolic fraction, from olive leaves and fruits, have been suggested, and a potential application in gut inflammation has been supported by in vitro and IBD-animal models studies. In the present review, we first introduced the potential therapeutic role of olive tree biophenolsin chronic inflammatory disease. Then, we aimed to describe their most interesting application for gut inflammation, as the results of basic science studies and animal experimental models. Finally, the potential role of olive tree biophenols in the setting of human IBD is discussed.

Keywords: Crohn’s disease; biophenols; hydroxytyrosol; inflammatory bowel disease; nutraceuticals; oleuropein; olive leaves; olive oil; ulcerative colitis.

Figure 1

Molecular mechanisms of most investigated vegetable-derived biophenols (other than olive-derived) potentially involved in inflammatory bowel disease treatment. The red arrows pointing up indicate an increase while the red arrows pointing down indicate a decrease. MPO: myeloperoxidase; IFN-γ: interferon-gamma; NF-κB: nuclear factor kappa-light-chain-enhancer of activated B cells; MAD: malondialdehyde; PGE₂: Prostaglandin E2; TLR-4: toll-like receptor-4; IL: interleukin; TNF-α: tumor necrosis factor-alpha; COX-2: cyclooxygenase-2; IKK: I kappa B kinase; iNOS: inducible nitric oxide synthase; JNK: c-Jun N-terminal kinase; ERK: extracellular signal regulated kinases; MIF-2: macrophage migration inhibitory factor-2; MCP-1: monocyte chemoattractant protein-1; MAPK: mitogen-activated protein kinase; MIG: monokine induced by gamma interferon.

Figure 2

Classification of olive tree biophenols and most representative compounds.

Figure 3

The chemical structure of the main phenolic compounds derived from olive tree (adapted from [18]).

Figure 4

Chronic inflammatory diseases in which olive biophenols showed beneficial properties.

Figure 5

Biophenols from olive tree and intestinal inflammation: results from basic science and animal models. The red arrows pointing up indicate an increase while the red arrows pointing down indicate a decrease.