DPPH free radical scavenging activity
The stable radical DPPH has been used widely for the
determination of primary antioxidant activity, that is, the
free radical scavenging activities of pure antioxidant compounds,
plant and fruit extracts and food materials. The
assay is based on the reduction of DPPH radicals in
methanol which causes an absorbance drop at 515 nm.
In this study, the antioxidant activity was expressed as
Trolox equivalents per gram of plant material on a dry
basis as it is a more meaningful and descriptive expression
than assays that express antioxidant activity as the percentage
decrease in absorbance. As such the results provide
a direct comparison of the antioxidant activity with
Trolox.
The DPPH free radical scavenging activity of 25 plant
extacts are shown in Fig. 2. Local celery showed the lowest
DPPH free radical scavenging activity while ulam raja
leaves had the highest activity. Other than ulam raja; red
amaranthus, mint, laksa, tapioca, daun salam, sweet potato,
cekur manis and betel leaves also showed relatively high
DPPH free radical scavenging activitie