The antioxidant activities of chlorophyll extracts were also determined by the ABTS radicalscavenging
method. The advantages of this radical are its water-solubility and high absorption
coefficient at long wavelengths, allowing the determination of its rate of consumption with minimal
interferences (Campos and Lissi, 1997; Maisuthisakul et. al., 2007). In the present study, an apex and
the young leaves showed higher of the scavenging of ABTS than old leaves (Table 2). For the FRAP
assay, the antioxidant activity in an apex was the highest (364.66±5.80 μmol TE/g dry weight). Apex
chlorophyll extracts performed the best ferrous ion chelating ability compared to the young leaves and
old leaves (Table 2). Pigments and phenolic compounds are the major group of compounds that
contribute to the overall antioxidant activities of plant foods (Ajila et. al., 2007). The mechanism of
antioxidant activity displayed by the natural chlorophyll derivatives does not seem to be based on the
ability to donate hydrogen but may be, on the protection of linoleic acid against oxidation and/or
preventing decomposition of hydroperoxides. The high antioxidant activity found for chlorophyll b, in
comparison to chlorophyll a, demonstrated the importance of the aldehyde group for functionality
(Ferruzzi et. al., 2002). For phenolic compounds is mainly as free radical scavengers, hydrogen
donators and singlet oxygen quenchers. In addition, they have a metal chelating potential
(Maisuthisakul, 2007). The results demonstrated that, phenolic compounds may not be the only
compounds responsible for the antioxidant activity, but also including the chlorophylls pigment of the
extracts from Gnetum gnemon Linn. leaves.
CONCLUSION