The antioxidant activity of H. rhamnoides on inhibition of lipid
peroxidation was determined using ferric thiocyanate assay
(Kikuzaki and Nakatani, 1993). A mixture containing the
plant extract 4 ml in absolute ethanol, 2.51% linoleic acid in
absolute ethanol (4.1 ml), 0.05 M phosphate buffer pH 7
(8 ml) and distilled water (3.9 ml) was placed in a vial with a
screw cap. The vial was placed in an oven at 40 C in the dark.
To 0.1 ml of the above solution 9.7 ml of 75% ethanol and
0.1 ml of 30% ammonium thiocyanate were added. Three minutes
after adding 0.1 ml of 0.02 M ferrous chloride in 3.5%
hydrochloric acid to the reaction mixture, the absorbance
was measured at 500 nm, every 24 h until the absorbance of
the control (without sample) reached maximum. a-tocopherol
was used as standard