Antioxidant Activities of Methyl Ricinoleate and Ricinoleic Acid Dominated Ricinus communis Seeds Extract Using Lipid Peroxidation and Free Radical Scavenging Methods
Abstract:
The antioxidant activity of two methanolic fractions (C1, C2) of R. communis
was determined by three methods: Lipid peroxidation by ferric thiocyanate method
and free radical scavenging effect on 2, 2-diphenyl-1-picrylhydrazyl radical
(DPPH) and hydroxyl radical generated from hydrogen peroxide. C1 and C2 at various
concentration possessed significant antioxidant activity (p<0.05) when compared
with antioxidant standards Butylated Hydroxy Anisole (BHA), ascorbic acid and
α-tocopherol used in the assay. C1 had percentage inhibition of 93.98%
while C2 gave 90.10% inhibition at 0.8 mg mL-1 in the lipid peroxidation/ferric
thiocyanate test. In the DPPH assay, C1 had inhibition of 73.71% while C2 gave
87.92% at 1.0 mg mL-1. While in the hydroxyl radical scavenging assay,
the inhibition of C1 was 85.07% while that of C2 was 94.91% at 0.1 mg mL-1,
both extracts therefore, showed comparative antioxidant activities at the concentrations
used. C1 golden brown coloured oil was analysed using gas chromatography/gas
chromatography-mass spectrometry. Four components were obtained, Methyl ricinoleate
(46.68%), Ricinoleic acid (34.41%), (Z, Z)-9, 12-Octadecadienoic acid (12.99%)
and (Z, Z)-9, 12-Octadecadienoic acid, methyl ester (5.92%). These chemical
constituents were assumingly responsible for the observed antioxidant activities
of methanolic extracts from R. communis seeds.
Ganiyat K. Oloyede , 2012. Antioxidant Activities of Methyl Ricinoleate and Ricinoleic Acid Dominated Ricinus communis Seeds Extract Using Lipid Peroxidation and Free Radical Scavenging Methods. Research Journal of Medicinal Plant, 6: 511-520.
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