Table 3.
Linear and non-linear relations obtained for different antioxidant concentrations (μM) applied against DPPH radicals in methanol or aqueous methanol after standard and modified reaction times (radical solution in methanol). In case of linear relations, slope (a), correlation coefficient (r) and lower/upper linearity limits if occurring (MIN/MAX–as % of Acontr) were shown; in case of a non-linear relationship, equation type and correlation coefficient were shown.
| Antioxidant | 50% MeOH + MeOH 30 min |
80% MeOH + MeOH 30 min |
MeOH 10 min |
MeOH 30 min |
MeOH 120 min |
|---|---|---|---|---|---|
| gallic acid | a = −69 r = −0.997 |
a = −65 r = −0.996 MIN = 20% |
a = −46 r = −0.996 |
a = −59 r = −0.996 |
a = −49 r = −0.996 |
| ferulic acid | a = −12 r = −0.993 MIN = 40% |
a = −12 r = −0.993 MIN = 40% |
power r = −0.994 |
a = −14 r = −0.999 MIN = 50% |
power r = −0.995 |
| catechin | a = −23 r = −0.995 MIN = 20% |
a = −27 r = −0.997 MIN = 10% MAX = 90% |
a = −19 r = −0.994 MIN = 40% |
a = −22 r = −0.998 |
a = −34 r = −0.996 MIN = 20% |
| quercetin | N.A. 1 | a = −63 r = −0.999 |
a = −32 r = −0.999 MIN = 20% |
a = −57 r = −0.999 MIN = 15% |
a = −49 r = −0.998 |
| propyl gallate | a = −52 r = −0.998 |
a = −53 r = −0.998 |
a = −47 r = −0.997 |
a = −63 r = −0.999 |
a = −47 r = −0.998 |
| glutathione | power r = −0.996 |
N.A. | N.A. | N.A. | N.A. |
| carnosine | N.D. 2 | N.A. | N.A. | N.A. | N.A. |
| cysteine | a = −12 r = −0.999 |
N.A. | N.A. | N.A. | N.A. |
| histidine | TR. 3 | N.A. | N.A. | N.A. | N.A. |
| ascorbic acid | a = −22 r = −0.999 MIN = 10% MAX = 90% |
a = −24 r = −0.999 |
a = −22 r = −0.995 MIN = 10% MAX = 90% |
a = −29 r = −0.997 MIN = 20% |
a = −22 r = −0.995 |
| ascorbyl palmitate | N.A. | N.A. | a = −22 r = −0.999 |
a = −22 r = −0.998 |
a = −21 r = −0.998 |
| α-tocopherol | N.A. | N.A. | a = −22 r = −0.999 |
a = −25 r = −0.998 |
a = −22 r = −0.999 |
| tocopheryl acetate | N.A. | N.A. | N.D. | N.D. | N.D. |
| Trolox | a = −22 r = −0.999 |
a = −24 r = −0.999 |
a = −46 r = −0.999 |
a = −51 r = −0.999 |
a = −47 r = −0.993 |
| phenolic mixture | a = −40 r = −0.995 MIN = 20% |
N.T. 4 | a = −22 r = −0.995 MIN = 25% |
a = −24 r = −0.997 MIN = 20% |
a = −26 r = −0.993 |
| polar mixture | a = −27 r = −0.995 MIN = 20% |
N.A. | N.A. | N.A. | N.A. |
| applicable compounds mixture | N.A. | N.A. | a = −19 r = −0.999 MIN = 20% |
a = −20 r = −0.998 MIN = 20% |
a = −25 r = −0.997 MIN = 30% |
1 N.A.—not applicable. 2 N.D.—activity not detected. 3 TR.—traces of activity. 4 N.T.—not tested.