Figure 3

Antioxidant activity of CDs (a) DPPH free radical scavenging property of CDs (b) optical images of DPPH solution showing a gradual colour change (wine red to yellow) with the concentration increase of CDs (c) TAC activity by Phosphomolybdate assay (d) optical images of the TAC activity showing a gradual colour change (light green to deep greenish-blue) with the concentration raise of CDs.