Table 6.
Biomarkers of oxidative stress in tissues at the end of the study.
| Coconut | Soybean | EPA/DHA 1:1 | 80% DHA | p-Value | |
|---|---|---|---|---|---|
| Perigonadal adipose tissue | |||||
| SOD (U/g tissue) | 226 ± 45 | 237 ± 44 | 236 ± 61 | 225 ± 36 | NS * |
| CAT (mmol/g tissue) | 0.11 ± 0.02 | 0.09 ± 0.01 | 0.11 ± 0.02 | 0.10 ± 0.03 | NS † |
| GPx (U/g tissue) | 0.54 ± 0.20 | 0.58 ± 0.18 | 0.50 ± 0.16 | 0.41 ± 0.20 | NS * |
| GR (U/g tissue) | 0.40 ± 0.07 | 0.46 ± 0.10 | 0.39 ± 0.11 | 0.35 ± 0.08 b | 0.047 † |
| GSH (nmol/g tissue) | 0.93 ± 0.23 | 1.05 ± 0.15 | 1.03 ± 0.19 | 0.91 ± 0.14 | NS * |
| GSSG (nmol/g tissue) | 4.43 ± 0.58 | 4.56 ± 0.93 | 4.05 ± 0.52 | 4.53 ± 1.05 | NS * |
| GSSG/GSH ratio | 5.10 ± 1.78 | 4.46 ± 1.26 | 4.03 ± 0.67 | 5.11 ± 1.44 | NS † |
| Conjugated dienes (mmol hydroperoxides/kg lipid) | 9.87 ± 1.43 | 8.83 ± 2.03 | 10.33 ± 2.75 | 10.83 ± 2.86 | NS * |
| TBARS (nmol MDA Eq/g tissue) | 2.41 ± 2.16 | 3.18 ± 2.51 | 4.95 ± 2.47 a | 4.99 ± 2.64 a | 0.046 † |
| Liver | |||||
| SOD (U/g tissue) | 6411 ± 631 | 6879 ± 1046 | 6577 ± 872 | 6083 ± 829 | NS * |
| CAT (mmol/g tissue) | 10.8 ± 1.3 | 11.1 ± 0.5 | 11.4 ± 1.2 | 11.8 ± 0.7 | NS * |
| GPx (U/g tissue) | 29.5 ± 5.2 | 25.1 ± 2.9 | 26.8 ± 2.9 | 26.0 ± 3.2 | NS * |
| GR (U/g tissue) | 6.80 ± 1.19 | 7.62 ± 2.34 | 7.78 ± 2.00 | 7.53 ± 1.73 | NS * |
| GST (U/g tissue) | 113 ± 11 | 115 ± 22 | 104 ± 21 | 103 ± 16 | NS * |
| GSH (µmol/g tissue) | 2.22 ± 0.55 | 2.22 ± 0.59 | 2.09 ± 0.52 | 2.08 ± 0.60 | NS † |
| GSSG (µmol/g tissue) | 1.47 ± 0.20 | 1.38 ± 0.23 | 1.30 ± 0.16 | 1.23 ± 0.11 | 0.048 * |
| GSSG/GSH ratio | 0.71 ± 0.25 | 0.65 ± 0.20 | 0.66 ± 0.21 | 0.63 ± 0.16 | NS * |
| XO (mU/g tissue) | 96 ± 26 | 121 ± 36 | 89 ± 15 | 88 ± 20 | 0.022 * |
| Protein carbonylation index | 2.73 ± 0.68 | 2.11 ± 0.57 | 2.43 ± 0.67 | 3.05 ± 0.35 b | 0.007 * |
| Conjugated dienes (mmol hydroperoxides/kg lipid) | 20.7 ± 2.3 | 20.6 ± 1.3 | 21.9 ± 1.5 | 21.0 ± 2.8 | NS * |
| TBARS (nmol MDA Eq/g tissue) | 217 ± 72 | 229 ± 115 | 278 ± 90 | 320 ± 94 | NS * |
Values are expressed as mean ± standard deviation, n = 10 rats/group. Abbreviations: EPA, eicosapentaenoic acid; DHA, docosahexaenoic acid; SOD, superoxide dismutase; NS, not significant; CAT, catalase; GPx, glutathione peroxidase; GR, glutathione reductase; GSH, reduced glutathione; GSSG, oxidized glutathione; TBARS, thiobarbituric acid-reactive substances; MDA Eq, malondialdehyde equivalent; GST, glutathione S-transferase; XO, xanthine oxidase. * p-value was calculated by the one-way analysis of variance followed by the Scheffé post hoc test. † p-value was calculated by the non-parametric Kruskal–Wallis test followed by the Mann–Whitney U test. The level of statistical significance was set at p-value < 0.05. a vs. coconut, b vs. soybean, c vs. EPA/DHA 1:1.