Determination of DPPH radical scavenging
activity—The antioxidant activity was assessed
using the stable DPPH radical5. The reaction mixture
contained 300 of TSCEs at various concentrations
and 2 mL of 0.1 mM DPPH in methanol was
incubated in a dark room for 30 min. The
decolourized purple to yellow mixture was observed
in the presence of antioxidant, and the absorbance
was measured at 517 nm against a methanol blank.
The DPPH radical scavenging activity was calculated
using the following equation: