Table 3.
Effect of long-term storage on the free radical scavenging activity of 21 South African medicinal plants
| Plant species | Plant part |
Radical scavenging activity (%) at 100 μg/ml |
EC50(μg/ml) |
Antioxidant activity index |
|||
|---|---|---|---|---|---|---|---|
| Stored | Fresh | Stored | Fresh | Stored | Fresh | ||
|
Acokanthera oppositifoliaδ |
Roots |
93.3 ± 0.03 ** |
92.6 ± 0.10 |
26.8 ± 2.43 * |
18.0 ± 0.34 |
0.7 ± 0.06 ** |
1.1 ± 0.02 |
|
Artemisia afra# |
Aerial parts |
93.8 ± 0.11 * |
92.7 ± 0.34 |
9.3 ± 0.07 *** |
12.4 ± 0.15 |
2.1 ± 0.02 *** |
1.6 ± 0.02 |
|
Artemisia afraδ |
Aerial parts |
94.0 ± 0.07 * |
92.7 ± 0.34 |
6.8 ± 0.50 *** |
12.4 ± 0.15 |
2.9 ± 0.21 ** |
1.6 ± 0.02 |
|
Buddleja salviifolia# |
Leaves |
96.2 ± 0.06 *** |
93.0 ± 0.40 |
15.5 ± 0.47 ** |
10.0 ± 0.61 |
1.3 ± 0.04 ** |
2.0 ± 0.12 |
|
Buddleja salviifolia# |
Twigs |
94.2 ± 0.13 ns |
94.3 ± 0.15 |
17.2 ± 0.32 ns |
17.5 ± 0.40 |
1.1 ± 0.02 ns |
1.1 ± 0.03 |
|
Clausena anisata# |
Leaves & Twigs |
70.8 ± 0.28 ns |
72.6 ± 6.21 |
33.2 ± 3.89 ns |
26.8 ± 2.06 |
0.6 ± 0.07 ns |
0.7 ± 0.06 |
|
Cussonia spicata# |
Leaves |
93.7 ± 0.07 *** |
61.6 ± 1.67 |
14.3 ± 0.22 ** |
43.6 ± 5.73 |
1.4 ± 0.02 *** |
0.5 ± 0.07 |
|
Dombeya rotundifolia# |
Leaves |
96.5 ± 0.56 ** |
93.6 ± 0.27 |
5.9 ± 0.12 ns |
6.1 ± 0.32 |
3.3 ± 0.07 ns |
3.2 ± 0.16 |
|
Ekebergia capensisδ |
Leaves & Twigs |
94.2 ± 0.42 * |
92.8 ± 0.30 |
4.7 ± 0.37 ** |
25.5 ± 4.99 |
4.3 ± 0.32 *** |
0.8 ± 0.14 |
|
Leonotis intermediaδ |
Leaves |
93.3 ± 0.09 * |
88.5 ± 1.73 |
10.6 ± 0.37 *** |
51.7 ± 0.32 |
1.9 ± 0.06 *** |
0.4 ± 0.00 |
|
Leonotis leonurusδ |
Leaves |
93.7 ± 0.18 ** |
91.6 ± 0.43 |
16.8 ± 0.06 *** |
30.3 ± 0.92 |
1.2 ± 0.00 *** |
0.7 ± 0.02 |
|
Merwilla plumbeaδ |
Bulbs |
8.2 ± 0.61 ** |
2.6 ± 0.97 |
ND |
ND |
ND |
ND |
|
Ocotea bullataδ |
Bark |
95.0 ± 0.25 ** |
93.8 ± 0.02 |
3.2 ± 0.14 ** |
4.3 ± 0.10 |
6.3 ± 0.28 ** |
4.6 ± 0.11 |
|
Olea europaea# |
Leaves |
94.9 ± 0.20 ** |
93.2 ± 0.09 |
14.0 ± 0.48 *** |
20.0 ± 0.16 |
1.4 ± 0.05 *** |
1.0 ± 0.01 |
|
Pittosporum viridiflorum# |
Leaves & Twigs |
93.6 ± 0.10 ns |
93.8 ± 0.29 |
17.9 ± 0.25 ns |
17.5 ± 0.27 |
1.1 ± 0.02 ns |
1.1 ± 0.02 |
|
Plumbago auriculataδ |
Leaves |
50.6 ± 3.97 ns |
54.6 ± 1.15 |
ND |
ND |
ND |
ND |
|
Protorhus longifoliaδ |
Leaves |
95.8 ± 0.24 ** |
97.3 ± 0.21 |
2.2 ± 0.16 ns |
2.3 ± 0.14 |
9.1 ± 0.71 ns |
8.5 ± 0.49 |
|
Solanum mauritianumδ |
Leaves |
34.4 ± 0.73 *** |
19.8 ± 1.53 |
ND |
ND |
ND |
ND |
|
Spirostachys africana# |
Leaves & Twigs |
96.6 ± 0.06 *** |
91.8 ± 0.34 |
2.0 ± 0.07 *** |
14.4 ± 0.58 |
10.0 ± 0.35 *** |
1.4 ± 0.06 |
|
Synadenium cupulareδ |
Leaves |
90.9 ± 0.70 *** |
46.0 ± 5.30 |
55.7 ± 0.35 |
ND |
0.4 ± 0.02 |
ND |
|
Tetradenia ripariaδ |
Leaves |
68.5 ± 1.39 *** |
23.8 ± 2.44 |
41.0 ± 5.29 |
ND |
0.5 ± 0.06 |
ND |
|
Trichilia dregeana# |
Leaves & Twigs |
95.8 ± 0.46 ** |
92.3 ± 0.16 |
5.3 ± 0.02 *** |
14.6 ± 0.24 |
3.7 ± 0.01 *** |
1.3 ± 0.02 |
|
Ziziphus mucronata# |
Leaves |
90.7 ± 0.42 ns |
89.0 ± 2.20 |
29.7 ± 1.02 ns |
30.9 ± 1.94 |
0.7 ± 0.02 ns |
0.6 ± 0.04 |
|
Ziziphus mucronataδ |
Leaves |
91.1 ± 0.18 ns |
89.0 ± 2.20 |
18.1 ± 0.29 ** |
30.9 ± 1.94 |
1.1 ± 0.02 *** |
0.6 ± 0.04 |
| Ascorbic acid |
96.6 ± 0.04 |
|
2.1 ± 0.05 |
|
9.4 ± 0.23 |
|
|
| Butylated hydroxytoluene | 93.2 ± 0.34 | 3.0 ± 0.04 | 6.5 ± 0.09 | ||||
ns = not significant; P = 0.05 (*); P = 0.01 (**); P = 0.001 (***).
ND = not determined.
δ = Plant material stored for 16 years.
# = Plant material stored for 12 years.