14 675 nm. Gallic acid was used as the standard and total phenol content was
expressed as gallic acid equivalent GAE gkg of fresh amaranth leaves.
2.6. Statistical analysis Data were expressed as means of three replications.
3. Results and Discussion
Results obtained for radical scavenging capacity and total phenol content of the leaves of amaranth accessions are presented in Fig 1. Accession number
9, 5, 3 and 4 of A. hybridus, A. dubius and A. cruentus exhibited the strongest inhibition capacity of DPPH free radicals. On the other side, the
weakest radical scavenging activity was in the group of A. tricolor accession number 14, 15 and 16. The lowest the IC
50
represents the strongest the capacity of leaves extract to reduce 50 percent of DPPH
radicals because it is required small amount of leaves to neutralize 50 percent of free radical. IC
50
of the amaranth leaves ranged from 1.3 to 18.3 mg fresh leavesml that was in accordance to [9]. As comparison with the
common antioxidant in the food industry, ascorbic acid and butylated hydroxytoluene BHT has IC
50
of 2.1 m
μgml and 13.2 μgml respectively [12]. The leaves of amaranth had around thousand times lower capacity of
antioxidant than the common antioxidants because it was calculated from the raw material instead of concentrate. Therefore, the antioxidant capacity
of amaranth leaves was still comparable to the common antioxidants.
Figure 1. Radical scavenging activity IC
50
and total phenol content of the leaves of amaranth accessions
0,0 2,0
4,0 6,0
8,0 10,0
12,0 14,0
16,0
IC50 mgml Phenol g GAEkg FW
15 Among the amaranth types, the leaves of grain amaranths exhibited the
strongest radical scavenging activity compared to weedy and vegetable amaranths Fig 2. This result indicated the potential of grain amaranths for
healthy food industry as their grain and leaves could be harvested.
Figure 2. Comparison of radical scavenging capacity and total phenol content of the leaves of different amaranth type
The results expressed weak correlation between the total phenol content and IC
50
r = –0.51. This was in accordance to [3] where the antioxidant
properties were not only determined by the phenolic compounds but also by non-phenol antioxidants such as ascorbic acid, tocopherols, flavonoids,
unsaturated fatty acids and lectins. The compounds with radical scavenging activity or antioxidant in leafy amaranth are important to be explored to
know further its potential as healthy food properties.
4. Conclusions
Amaranth leaves have strong radical scavenging activity and could be used as antioxidant for healthy food industries.
Acknowledgment
Acknowledgment is going to Mrs. Rita Andini and Mr. David M. Brenner for the provision of amaranth seeds as well as to DAAD who has provided
financial support for this workshop.
5. References
[1] G.J.H. Grubben. 1994. Amaranthus L. in Siemonsma JS, Piluek K eds Prosea: Plant Resources of South-East Asia 8. Vegetables. Prosea
Foundation, Bogor, pp 82-86.
0,0 1,0
2,0 3,0
4,0 5,0
6,0
GR WD
VG IC50 mg FWml
Total Phenol g GAEkg FW
