Table 4.
Relevant studies dealing with the ex vivo antioxidant capacity of carotenoids in LDLs.
| Experimental Approach | Participants; Supplementation Protocol; Biomarkers of Oxidative Stress; Relevant Methodologies | Carotenoids | Observed Effect | Reference |
|---|---|---|---|---|
| Supplementation/ex vivo LDL oxidation | Group of male nonsmokers and smokers; supplementation with β-carotene (2 × 20 mg daily for two weeks, and then 20 mg daily for 12 weeks); lipid peroxidation of LDL isolates [112] | β-carotene | No protective effect of LDL susceptibility to oxidation despite the observed increase in plasma β-carotene levels | [113] |
| Supplementation/ex vivo biomarkers of oxidative stress | Group of 11 smokers and 11 nonsmokers; supplementation with fruits and vegetables providing 30 mg carotenoids/day for 2 weeks; lipid peroxidation of LDL isolate supplementation, oxidative stress biomarkers of plasma [112] | α-carotene, β-carotene, lutein, lycopene, α-cryptoxanthin, β-cryptoxanthin | Inhibition of LDL susceptibility to oxidation for the smokers and nonsmokers. LDL resistance to oxidation increased 14% in smokers and 28% in the nonsmokers group after supplementation | [114] |
| Supplementation/ex vivo biomarkers of oxidative stress | Group of 32 healthy volunteers; double-blind randomized, placebo-controlled trial, supplementation with a mixture of carotenoids providing 7.6 mg carotenoids/day for 3 weeks; lipid peroxidation of LDL isolates, DNA damage, ORAC [8,112] | Lycopene, palm oil carotenes, marigold extract carotenoids, paprika carotenoids, bixin | The carotenoid supplementation reduced the LDL oxidizability (by 20.4% in the supplemented group) and DNA damage assessed by urine biomarkers; the effect was not observed with the ORAC assay | [115] |
| Supplementation/ex vivo biomarkers of oxidative stress | Group of 105 healthy volunteers; randomized, double-blind, placebo-controlled; commercial spread providing with a mixture of carotenoids at different doses for 11 weeks; lipid peroxidation of LDL isolates, plasma FRAP, MDA, serum arylesterase activity, plasma F2α-isoprostanes; [28,112] | Lycopene, lutein, α-carotene, β-carotene | Moderate amounts of carotenoids resulted in a significantly increased resistance of LDL to oxidation and lower plasma peroxidation biomarkers (17% increase of LDL resistance to oxidation, 18% increase of lag-phase, and 15% reduction in the F2-isoprostane level) | [116] |
| Supplementation/ex vivo LDL oxidation | Group of 12 healthy female volunteers; supplementation with tomato products providing 8 mg lycopene/day for 21 days; lipid peroxidation of LDL isolates, urinary 8-iso-PGF2α [112,117] | Lycopene | Decrease in LDL oxidizability (22%) and significant lower excretion of 8-iso-PGF2α (53%) regarding the values reached in the control group | [118] |
| In vitro loading of LDL/biomarkers of oxidative stress | Group of 10 volunteers donated plasma samples for LDL isolation; in vitro loading was performed with lycopene or lutein via emulgent and incubation; lipid peroxidation and oxidation of ApoB of LDL isolates [108] | Lycopene, lutein | Carotenoids were not effective antioxidants of the LDL | [119] |
| Group of 35 patients with T2DM; double-blind, placebo-controlled; supplementation with lycopene, 10 mg/day for 8 weeks; total antioxidant capacity assessed via ABTS, MDA, humoral immunity biomarkers | Lycopene | Increased ratio of total antioxidant capacity to MDA values and attenuated pro-atherogenic immune response | [120] | |
| Supplementation/ex vivo LDL oxidation | Group of 77 healthy male and female volunteers; double-blind randomized, placebo-controlled trial, lycopene supplement at different doses for 8 weeks; lipid peroxidation of LDL isolates, MDA and HNE, urinary 8-iso-PGF2α, DNA damage markers | Lycopene | Significant decrease in DNA damage (8.9%) and urinary 8-iso-PGF2α levels (23%) in the supplemented group; no significant effect was observed in biomarkers of lipid peroxidation | [121] |
| Supplementation/ex vivo biomarkers of oxidative stress | Group of 126 healthy men; randomized placebo-controlled trial, lycopene supplementation at different doses for 8 weeks; SOD activity in plasma, DNA damage, biomarkers of endothelial function | Lycopene, β-carotene | Increase in SOD activity (2.37 units/mL) and prevention of DNA damage (for the 15 mg/day suppl. group); beneficial effects in subjects with relatively impaired endothelial cell function | [122] |
Abbreviations: SOD: superoxide reductase; suppl.: supplemented; T2DM: type 2 diabetes mellitus.