Oxygen radical absorbance capacity (ORAC) was determined
according to Ou et al. (2001). Fluorescein (100 μL, 500 mM) and
25 μL of diluted Pelargonium sidoides extracts were added into each
working well in a microplate (96 well) preincubated at 37 1C.
Thereafter, 25 μL of 250 mM AAPH was quickly added and the
microplate was shaken for 5 s in a microtiter plate fluorometer
Multiskan Ascent instrument (Labsystems, Helsinki, Finland). The
fluorescence (Ex. 485 nm, Em. 510 nm) was read every 3 min over
90 min. The net area under the curve was used to calculate
antioxidant capacity which was expressed in trolox equivalents (TE)