Table 2.

Animal studies on olive oil polyphenols and intestinal inflammation.

Study	Cell Type	Intervention	Results
Reddy et al. [53]	DSS-colitis rat model, and Caco-2 cells treated with t-butyl hydroperoxide	Oleic acid and HT, fish oil, MCT	Synergistic anti-inflammatory effect between olive oil PP and fish oil; MCT increased disease activity
Sanchez-Fidalgo et al. [54]	Chronic mouse DSS-colitis model	EVOO diet enriched with HT	↓ disease activity index ↑ histological signs ↓ 50% reduction in mortality ↓ TNF-α, iNOS, and p38MAPK ↑ IL-10
Sanchez-Fidalgo et al. [55]	Chronic mouse DSS-colitis model	EVOO enriched with polyphenols	↓ MCP-1, TNF-α, COX-2 and iNOS expression
Sanchez-Fidalgo et al. [56]	Acute ulcerative colitis model in mice	EVOO’s unsaponifiable fraction (UF)	↓ MCP-1 and TNF-α levels, iNOS, COX-2, and p38MAPK ↑ IκB expression
Takashima et al. [57]	Chronic DSS-induced colitis in rats	EVOO diet (5% of weight)	↓ STAT3, pSTAT3, COX-2 and iNOS ↓ cell proliferation (PCNA) ↑ apoptosis (caspase-3)
Carrielo et al. [58]	Mouse model of DSS-induced colitis	EVOO from 4 Apulian cultivars	↑ intestinal morphology ↓ body-weight loss ↓ rectal bleeding ↓ IL-1β, TGFβ, IL-6 gene expression
Sanchez-Fidalgo et al. [59]	DSS-colitis-associated colon carcinogenesis in mice	EVOO enriched diet	↓ incidence and multiplicity of tumours
Nascimento et al. [60]	Mouse model of DSS-induced colitis	EVOO and flaxseed oil	↓ IL-6 No differences in disease activity index (DAI), histopathological score, interleukin (IL)-1β, and iNOS between the DSS and treatment groups
Huguet-Casquero et al. [61]	Activated macrophages (J774), murine model of acute colitis	Oleuropein (OLE) and OLE loaded with nanostructured lipid carriers	↓ MPO activity, TNF-α and IL-6
Voltes et al. [62]	Wistar rat model of TNBS-induced colitis	Intrarectal administration of aqueous solution containing olive oil and HT	↓ inflammatory infiltrate
Bigagli et al. [64]	Colitis induced in HLA-B27 transgenic rats	AIN-76 diet containing 10% corn oil or extra-virgin olive oil with high (EVOO) or low phenolic content (ROO)	No differences in disease signs like diarrhoea, myeloperoxidase activity, and mucosal injury

Abbreviations: EVOO: extra-virgin olive oil, IL-1B: interleukin 1 beta, TGFB: tumour growth factor B, MPO: myeloperoxidase, MCP-1: monocyte chemoattractant protein-1, IĸB: inhibitor of ĸappa B, COX 2: cyclooxygenase 2, DSS: dextran sulphate sodium, TNBS: trinitrobenzenesulfonic acid, MAPK: mitogen activated protein kinase, TNF-α: tumour necrosis factor alpha, MCT: medium chain triglyceride, HT: hydroxytyrosol, AIN-76: purified rodent diet, STAT3: signal transducer and activator of transcription 3, PCNA: proliferating cellnuclear antigen, ↓ = decrease in, ↑ = increase in.