Table 3.
Total phenolic content (TPC), antioxidant activity measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods.
| Sample | Extract | Yield (g/100 g Seaweed dw) | TPC (g GAE/100 g Extract) | DPPH (g AAE/100 g Extract) | FRAP (g BHAE/100 g Extract) |
|---|---|---|---|---|---|
| U. rigida | RTWE | 43.1 ± 0.7 b | 0.23 ± 0.03 b | nd | 0.08 ± 0.02 d |
| HWE | 46.2 ± 0.6 a | 0.16 ± 0.02 b | nd | 0.17 ± 0.03 c | |
| Eth80 | 18.9 ± 1.8 c | 0.53 ± 0.07 a | 0.09 ± 0.01 a | 0.67 ± 0.04 a | |
| Acet70 | 16.2 ± 0.4 c | 0.48 ± 0.06 a | 0.08 ± 0.01 a | 0.53 ± 0.03 b | |
| Gracilaria sp. | RTWE | 30.7 ± 1.4 a | 0.59 ± 0.03 a | nd | nd |
| Eth80 | 23.3 ± 0.8 b | 0.49 ± 0.03 b | 0.04 ± 0.01 a | 0.23 ± 0.02 a | |
| Acet70 | 23.2 ± 1.6 b | 0.54 ± 0.01 a,b | 0.04 ± 0.00 a | 0.21 ± 0.03 a | |
| F. vesiculosus | RTWE | 27.8 ± 2.3 a | 1.48 ± 0.11 c | 0.57 ± 0.06 c | 2.90 ± 1.02 b |
| HWE | 30.5 ± 0.8 a | 1.74 ± 0.09 c | 0.77 ± 0.12 c | 3.23 ± 1.00 b | |
| Eth80 | 15.3 ± 1.8 b | 5.66 ± 0.26 a | 2.60 ± 0.28 a | 8.30 ± 1.04 a | |
| Acet70 | 18.2 ± 0.9 b | 3.91 ± 0.09 b | 1.47 ± 0.12 b | 8.03 ± 3.91 a | |
| S. latissima | RTWE | 40.2 ± 1.6 a,b,c | 0.47 ± 0.02 b | 0.20 ± 0.04 a | 0.68 ± 0.02 c |
| HWE | 44.3 ± 0.9 a | 0.78 ± 0.06 a | 0.25 ± 0.05 a | 1.06 ± 0.06 a | |
| Eth80 | 36.5 ± 2.2 b,c | 0.19 ± 0.02 c | 0.07 ± 0.02 b | 0.21 ± 0.02 d | |
| Acet70 | 37.5 ± 2.8 b | 0.52 ± 0.02 b | 0.25 ± 0.01 a | 0.87 ± 0.07 b |
nd—not detected. Different letters in the same column (for each seaweed) indicate significant differences (p < 0.05). Hot water extraction (HWE) of Gracilaria sp. was not obtained due to its high agar content which limits processing.