Table 1.
IC50 values of quercitrin and isoquercitrin in various antioxidant assays.
| Assays | Quercitrin μg/mL (μM) | Isoquercitrin μg/mL (μM) | Positive Controls | Ratio (1) | Ratio (2) | |
|---|---|---|---|---|---|---|
| Trolox μg/mL (μM) | BHA μg/mL (μM) | |||||
| DPPH• scavenging | 4.45 ± 0.17 (9.93 ± 0.38 a) | 5.89 ± 0.25 (12.68 ± 0.54 b) | 4.53 ± 0.11 (18.10 ± 0.44 c) | 4.42 ± 0.19 (24.53 ± 1.04 d) | 1.8 | 1.4 |
| Cu2+-Reducing | 8.91 ± 0.27 (19.87 ± 0.61 a) | 11.75 ± 0.36 (25.31 ± 0.78 b) | 15.68 ± 0.63 (62.66 ± 2.51 d) | 7.96 ± 0.28 (44.19 ± 0.69 c) | 3.2 | 2.5 |
| FRAP | 6.14 ± 0.29 (13.70 ± 0.65 b) | 5.71 ± 0.16 (12.30 ± 0.34 a) | 6.98 ± 0.11 (27.88 ± 0.47 d) | 4.61 ± 0.13 (25.60 ± 0.69 c) | 2.0 | 2.3 |
| •O2− scavenging | 39.45 ± 2.43 (87.99 ± 5.43 b) | 36.30 ± 2.24 (78.16 ± 4.83 a) | 34.31 ± 0.90 (137.08 ± 3.61 c) | N.D. N.D. | 1.6 | 1.8 |
Each IC50 value was calculated by linear regression analysis of the dose response curves in Figure 5. The mass units of the IC50 values (μg/mL) were converted to molar units, and the resulting values are shown in parentheses. The linear regression was analyzed using version 6.0 of the Origin professional software (OriginLab Corporation, Northampton, MA, USA). Each experiment was performed in triplicate, and the IC50 values were presented as the mean ± SD (standard deviation, n = 3). Means values (μM) with different superscripts (a, b, c, d) in the same row were significantly different (p < 0.05). N.D., not detected. Ratio (1) = IC50,Trolox:IC50,Quercitrin; Ratio (2) = IC50,Trolox:IC50,Isoquercitrin.