Rapid Thin Layer Chromatography screening for antioxidant activity was
carried out by spotting a concentrated ethanol and aqueous solutions of the extracts on silica gel
plates. The chromatograms were developed in methanol : ethyl acetate (2 : 1) after which it was
air-dried and sprayed with 0.2% w/v DPPH spray in methanol. The chromatograms were
visualized for the presence of yellow spots. The radical scavenging activity of leaf extracts was
performed according to the DPPH spectrophotometric method of Mensor et al.[9]. One ml of 0.3
mM DPPH methanol solution was added to 2.5 ml solution of the extract or standard (100, 200
and 300μg/ml) and allowed to react at room temperature for 30 min. The absorbance of the
resulting mixture was measured at 518 nm and converted to percentage antioxidant activity (AA
%), using the formula: