Antioxidant activity
The antioxidant activities of chlorophyll ethanolic extracts from Gnetum gnemon Linn. leaves
were measured by ABTS, DPPH and FRAP assays. The ABTS and DPPH radical scavenging assays
are the most effective methods for evaluating the concentration of radical-scavenging materials active by a chain-breaking mechanism (Niki, 1987). Moreover, the FRAP assay is based on the reduction of
the Fe3+-2,4,6-tripyridyl-S-triazine complex to the ferrous form (Fe2+). Antiradical activity determined in
term of EC50 by the DPPH radical scavenging method defined as the concentration of antioxidant
required for 50% scavenging of DPPH radicals in this specified time period, a lower value of EC50
indicates a higher antioxidant activity of the plant extracts. From the experiment, the DPPH radical
scavenging activity (EC50) values of chlorophyll extracts were lower than that of BHT (18.70 μg/ml)
which meant weak antioxidant activity