Alperujo extract, hydroxytyrosol, and 3,4-dihydroxyphenylglycol are bioavailable and have antioxidant properties in vitamin E-deficient rats--a proteomics and network analysis approach.
METHODS
Olive products are rich in phenolic compounds, which are natural antioxidants in vitro. We tested the in vivo effects of alperujo, an olive production by-product, as well as hydroxytyrosol and 3,4-dihydroxyphenylglycol (DHPG) isolated from alperujo, on indices and pathways of oxidative and metabolic stress in a vitamin E-deficient rat model.


RESULTS
Rats were fed a vitamin E-deficient diet for 10 weeks, followed by this diet supplemented with either 100 mg/kg diet dα-tocopherol, alperujo extract, hydroxytyrosol, or 10 mg/kg diet DHPG, for a further 2 weeks. We detected alperujo phenolics in tissues and blood, indicating they are bioavailable. Alperujo extract partially ameliorated elevated plasma levels of thiobarbituric acid reactive substances and also lowered plasma cholesterol levels, whereas hydroxytyrosol increased plasma triglyceride levels. Proteomics and subsequent network analysis revealed that hepatic mitochondrial aldehyde dehydrogenase (ALDH2), of which protein and activity levels were regulated by dα-tocopherol and olive phenolics, represents a novel central regulatory protein hub affected by the dietary interventions.


CONCLUSIONS
The in vivo free radical scavenging properties of olive phenolics appear relatively modest in our model. But alternative mechanisms, including regulation of ALDH2, may represent relevant antioxidant mechanisms by which dietary olive phenolics could have beneficial impact on cardiovascular health.
Rowett Institute of Nutrition & Health, University of Aberdeen, Bucksburn, Aberdeen, United Kingdom.
Guillermo
G
Rodríguez-Gutiérrez
Garry G
GG
Duthie
Sharon
S
Wood
Phil
P
Morrice
Fergus
F
Nicol
Martin
M
Reid
Louise L
LL
Cantlay
Thomas
T
Kelder
Graham W
GW
Horgan
Juan
J
Fernández-Bolaños Guzmán
Baukje
B
de Roos
D000444:Aldehyde Dehydrogenase / Q000378:metabolism; D000071396:Aldehyde Dehydrogenase, Mitochondrial; D000818:Animals; D000924:Anticholesteremic Agents / Q000191:economics / Q000378:metabolism / Q000627:therapeutic use; D000975:Antioxidants / Q000191:economics / Q000378:metabolism / Q000627:therapeutic use*; D004032:Diet / Q000009:adverse effects; D019587:Dietary Supplements / Q000191:economics; D004195:Disease Models, Animal; D005525:Food-Processing Industry / Q000191:economics; D005638:Fruit / Q000737:chemistry; D000960:Hypolipidemic Agents / Q000191:economics / Q000378:metabolism / Q000627:therapeutic use; D007220:Industrial Waste / Q000032:analysis / Q000191:economics; D007408:Intestinal Absorption; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives* / Q000378:metabolism / Q000627:therapeutic use; D024101:Mitochondrial Proteins / Q000378:metabolism; D031658:Olea / Q000737:chemistry*; D018384:Oxidative Stress; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000378:metabolism / Q000627:therapeutic use; D010936:Plant Extracts / Q000191:economics / Q000378:metabolism / Q000627:therapeutic use*; D011897:Random Allocation; D051381:Rats; D014811:Vitamin E Deficiency / Q000097:blood / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology
D000924:Anticholesteremic Agents; D000975:Antioxidants; D000960:Hypolipidemic Agents; D007220:Industrial Waste; D024101:Mitochondrial Proteins; D010936:Plant Extracts; C005975:3,4-dihydroxyphenylethanol; D008734:Methoxyhydroxyphenylglycol; D000444:Aldehyde Dehydrogenase; D000071396:Aldehyde Dehydrogenase, Mitochondrial; C505112:Aldh2 protein, rat; D010626:Phenylethyl Alcohol; C010117:3,4-dihydroxyphenylglycol