In the present study, assay of reducing activity was based on the reduction of Fe3+/ferricyanide complex to the ferrous form in presence of reductants (anti-oxidants) in the tested samples.
The Fe2+ was then monitored by measuring the formation of Perl’s Prussian blue at 700 nm.
Figure 7 shows the reducing power of the extracts of R. tuberosa and standards, using the potassium ferricyanide reduction method.
The reducing power of the extracts increased with increasing concentration