Table 3.
Antioxidant Compounds of Natural Dietary Products with Role in T Cell Function
| No. | Key antioxidants | Food products | Antioxidant role | T cell function | Reference |
|---|---|---|---|---|---|
| 1 | Catechin hydrate (CH) | Green Tea | Scavenger of free radicals, represses NO production | Reduces TNF-α production and increases the secretion of IL-2 in hPBMCs | (8) |
| 2 | Aliphatic C(17)-polyacetylenes | Carrot, celeriac, parsnip, and parsley | Potential antioxidant | Improves the helper T-cell function and shifts Th1/Th2 balance toward Th1 | (5, 50, 227) |
| 3 | Curcumin (diferuloylmethan) | Yellow component of turmeric | Antioxidant | Decreases Bax level and increases Bcl-2 in T cells by downregulation of the cytokine receptor γ-chain | (27, 142) |
| 4 | Epigallocatechin 3-gallate (EGCG) | Green Tea | Increases expression and activities of MnSOD, catalase, and GPX | Inhibits proliferation of T cell by blocking IL-2/IL2-R signaling. It also arrests T-cell growth by blocking 20S/26S proteasome complex, and subsequent inhibition of Ikk B |
(6, 158, 308) |
| 5 | Ajoene | Garlic | Antioxidant | At higher concentrations, it has inhibitory effects. At lower concentration, it increases lymphocyte proliferation |
(52, 134) |
| 6 | Chalcones (precursors of flavones) | Responsible for yellow pigmentation of plants | LPS-stimulated increase of iNOS expression and inhibits COX2, scavenger of hydroxyl radical | Inhibits proliferation of lymphocytes and blocks Th1/Th2 cytokine production. Cytoprotective activity for Jurkat cells in the G1 phase and cytotoxic for cells in the G2/M phase |
(21, 114, 242) (311) |
| 7 | OptiBerry (anthocyanin) | Wild blueberry, wild bilberry, and cranberry | MCP-1 and inducible NFκB transcriptions as well as the inflammatory biomarker IL-8 | Reduces T-cell proliferation and also reduces IL-2 and IL2-R | (52, 320) |
| 8 | Proanthocyanidin | Jamapa bean and grape seed | High anti-free-radical activity | Reduces H2O2-induced cell apoptosis and ROS. Reduces Tregs and CD4− Th17 cells |
(12, 125, 218) |
| 9 | Resveratrol | Peanuts | Antioxidant and anti-inflammatory agent | It suppresses the Treg in tumor-bearing mice and enhances the expression of IFN-γ in CD8− T cells | (42, 112, 316) |
| 10 | Lycopene | Tomatoes | Strong antioxidant effect | It increases antioxidant capacity and attenuates T-cell-dependent adaptive immune response | (41, 62, 205) |
| 11 | Beta-Carotene (Precursor of Vitamin A) | Carrots and other orange/yellow vegetables and fruit | Oxidizing hydroxyl radical, super oxide, and reducing free radicals | Treatment with beta-carotene enhances IL-2 and IFN-γ production by T lymphocytes | (62, 193, 312) |
| 12 | Vitamin A | Carrots, cheese, eggs, and meat | Antioxidant | Tropism of T cells to gut | (182) |
| 13 | Vitamin B6 | Whole grain, vegetables, and meat | Antioxidant | Suppresses proinflammatory cytokines | (113) |
| 14 | Vitamin C | Citrus fruit, the cabbage family, tomatoes, peppers, and greens | Attacks free radicals, including those from overexposure to sunlight. Boosts immunity and helps produce anti-inflammatory steroids | Vitamin C shifts immune responses toward Th1, which may be due to Vitamin C uptake by DCs increased IL-12p70 secretion | (62, 124) |
| 15 | Vitamin D | Cod liver oil and egg | Antioxidant | Tropism of T cell to skin. Important for TCR response. Naïve T cells do not express vitamin D receptor. It upregulates expression of phospholipase C-γ1, which is important for TCR activation |
(182, 298) |
| 16 | Vitamin E | Wheat germ oil and sunflower oil | Free-radical scavenger | Vitamin E suppresses CD95L and protects T cells of HIV-1-infected individuals from CD95-mediated AICD | (157) |
AICD, activation induced cell death; GPX, glutathione peroxidase; HIV, human immunodeficiency virus; hPBMCs, human peripheral blood mononuclear cells; IFN-γ, interferon-γ; iNOS, inducible NO synthase; MnSOD, manganese superoxide dismutase; ROS, reactive oxygen species; Th, T helper; TNF, tumor necrosis factor.