Table 2.
Flavanols: antioxidant and anti-inflammatory effects.
| Type of Study | Product/Compound | Dose/Duration | Intervention | Target | Outcome (S) | Reference |
|---|---|---|---|---|---|---|
| 2-year-old male Wistar rats (n = 48) | (-)-epicatechin | 2 and 10 mg/kg bw intragastric administration, during 5 weeks | DOCA-salt induced hypertension vs. DOCA-salt EPI2 and DOCA-salt EPI10 | Vascular Nox activity Protein expression of Nox p47phox and p22phox subunits |
DOCA-salt–EPI10 ↓ Nox activity in aortic rings by suppression of protein over-expression of p47phox and p22phox subunits and ↓ in ET-1 plasma levels Both DOCA-salt–EPI2 and EPI10 restored impaired endothelial function due to an ↑ in eNOS phosphorylation and a ↓ in O2− vascular content |
[56] |
| Double blind study with crossover-design in healthy volunteers (n = 10) | High-flavanol cocoa beverage (98 mg total flavanols: 183 mg epicatechin and 215 mg dimers) Low-flavanol cocoa beverage (80.4 mg total flavanols: 19.8 mg epicatechin and 23.1 mg dimers) |
54 g/200 mL of high or low-flavanol cocoa beverage | High-flavol cocoa (HFC) vs. low-flavanol cocoa (LFC) | Erythrocyte arginase activity | Ingestion of a high-flavanol cocoa beverage resulted in the highest decrease in erythrocyte arginase activity after 24 h (HFC: 3.0± 0.4; p < 0.05 vs. LFC: 3.5 ± 0.5 μmol urea mg protein-1 h-1) | [60] |
| Jurkat T cells culture HCAEC (human coronary artery endothelial cells) culture Obesity mice 2 months old C57BL |
Procyanidin A1, procyanidin A2, procyanidin B1 and procyanidin B2 (-)-epicatechin |
Cells (1×106 cells/ml) were pre-incubated with 2.5–50 μM A1, A2, B1 or B2 for 24 h Incubation of 0.1 nM-100 μmol/L during 10 minutes 1 mg epicatechin/kG Body weight 15 days |
Effect of preincubation of Jurkat T cells (further incubation with or without the addition of either TNF-α or PMA) Identification of epicatechin intracellular signaling pathways on eNOS-NO production Inflammatory status: TNF αand IL-6 |
NF-κB-DNA binding eNOS activation |
Pre-incubation (24 h) with B1 or B2 procyanidins (50 μM) ↓ NF-κB-Luc activity (34–52%) and ↓ by 80 and 85% IL-2 release in Jurkat cells subsequently treated with TNF-α or PMA A concentration-dependent (5-50μM) inhibition of NF-κB-DNA binding was observed in cells pre-incubated with B1 or B2 procyanidins At 100 nM, B1 and B2 caused a 29–38% and 38–47% inhibition of either p50 or RelA binding to its DNA consensus sequence Epicatechin (1 μM/L) induced eNOS activation via Ser1177 and Ser633 phosphorylation and Thr495 de-phosphorylation Epicatechin (1 μM/L) activated eNOS via Akt phosphorylation (induction of Ser1177 phosphorylation) Epicatechin stimulated dissociation of eNOS from Cav-1 and therefore stimulated its activation TNF α level decreased by 50 % while IL-6 decreased by 30% |
[62] [68] [69] |
| RAEC, BAEC and human umbilical endothelial cells (HUVEC) cultures |
(-)-epicatechin |
20 μM incubation for 24 h |
Protective effects of (-)-epicatechin against oxLDL protein damage |
NADPH oxidase (NOX) activity and oxLDL protein damage |
Pretreatment of BAEC and RAEC with epicate-chin prevented oxLDL-elicited downregulation of eNOS protein and par-tially the upregulation of iNOS protein In BAEC and HUVEC incubated with oxLDL, (-)-epicatechin showed a potent O2− scavenging activity and a strong inhibition of its production (10 μM) Pretreatment of HUVEC with (-)-epicatechin su-ppressed the formation of all 3 types of modified proteins (protein carbo-nyls and tyrosine-nitrated proteins) in a dose-dependent manner (com-plete inhibition at 10 μM) |
[67] |
| HUVEC culture |
(-)-epicatechin, its metabolites (3′-O-methyl epicatechin, 4′-O- methyl epicatechin) and pB2 |
0.1-100 μM incubation for 24 h |
Effect of pB2, epicatechin and its metabolites on NADPH oxidase activity |
NADPH oxidase (NOX) activity and O2− generation |
All 4 compouds (10 μM) inhibited O2− re-lease in Angiotensin-II estimulated HUVEC, after 24 h preincubation Methylated epicatechin metabolites proved to be Nox inhibitors (100 μM) without O2− scavenging activity Epicatechin showed O2− scavenging activity (100 μM) dependent on the duration of preincuba-tion, but did not affect NOX oxidation pB2 showed both inhibitory Nox and O2− scavenging activities |
[54] |
| Sprague–Dawley male rats (n = 10) |
Cocoa powder (11 mg epicatechin/g and 43 mg procyanidins/g) |
Purified egg white protein-based diet containing 40 g cocoa/kg diet, during 28 days |
Diet 0% cocoa vs. Diet 4% cocoa |
Renal arginase activity |
4% cocoa supplementation ↓ renal arginase activity, compared with control group (0.13 ± 0.02 vs. 0.18 ± 0.02 U/mg protein) |
[60] |
| HUVEC culture |
(-)-epicatechin flavanol metabolite mixture (2.6 μM total flavanols: 0.1 μM epicatechin and 2.15 μM epi-catechin metaboli-tes found in human plasma 2 h after high-flavanol cocoa beverage consumption) |
mix: 0.4, 2.6 and 7.8 μM epicatechin: 1, 3 and 10 μM 48 hour incubation |
Comparison between different concentrations of flavanol mix and epicatechin |
Arginase-2 (Arg-2) mRNA expression and activity |
Flavanol mix and epicatechin signifi-cantly ↓ Arg-2 mRNA expression in HUVEC, at 24 h in a dose-dependent manner Cells incubated with flavanol mix and epica-techin exhibited ↓ Arg-2 activity, at 48 h in a dose-dependent manner |
[60] |
| Randomized, crossover clinical trial in healthy volunteers (n = 18) |
Cocoa powder |
40 g cocoa powder (28.2mg epicatechin and 25.5 mg pB2/40 g) with 250 mL whole milk or water, during 3 weeks |
Cocoa powder with milk (CM) vs. cocoa powder with water (CW) |
NF-κB activation and protein expression of adhesion molecules (sICAM-1, sVCAM-1 and sE-selectin) in PBMC (periphe-ral blood mono-nuclear cells) |
CW significantly ↓NF-κB activation (determined by protein expression) after 6 h of ingestion, compared with CM Both CM and CW ↓ serum [sICAM-1] after intervention but only CW ↓ [sE-selectin] |
[34] |
| Human hepatoma HepG2, | (-)-Epicatechin (EC) and cocoa phenolic extract (CPE) | 10 µM EC or 1 µg//mL CPE were added to the cells for 24 h; |
Comparison between epicatechin and polyphenol extract | Nrf2; GPx, GX and CAT | Antioxidant exnzymes were regulating and Nfr2 has been stimulated. | [46] |
bw: body weight; DOCA-salt: deoxycorticosterone acetate and sodium chloride; EPI: (-)-epicatechin; Nox: NADPH oxidase; ET-1: endothelin-1; eNOS: endothelial nitric oxide synthase; O2−: superoxide; NO: nitric oxide; oxLDL: oxidized LDL; RAEC: rat aortic endothelial cells; BAEC: bovine aortic endothelial cells; iNOS: inducible nitric oxide synthase; pB2: procyanidin B2; NF-κB: nuclear factor κB; PMA: phorbol myristate acetate; TNF-α: tumor necrosis factor-alpha; Cav-1: caveolin-1. ↑ increased; ↓decreased.