Comparative Study of Antioxidant Activities of the Leaves and Stem of <i>Ipomoea aquatica</i> Forsk (Water Spinach)

Abstract

Leaves and stem extracts of Ipomoea aquatic Forsk were analysed for their antioxidant activities. Folin-Ciocalteu and AlCl₃ methods were used to quantify total phenolic and flavonoid contents while 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical assay was used to examine the antioxidant activity of the extracts. The respective total phenolic and flavonoid contents of the stem (18.00 ±  1.20 and 20.00 ± 1.40 μg Catechin equivalent, CEQ g^-1 DW) show no significant (p > 0.05) difference when compared to leaves (16.00 ± 1.10 and 30.00 ± 2.1 μg CEQ g^-1 DW). In DPPH scavenging assay, the reference standard i.e. vitamin C (IC₅₀ = 0.0660μg/ml) had significantly (p<0.05) higher scavenging activity than the stem (IC₅₀ = 35.96μg/ml) which in turn is significantly higher (p<0.05) than the leaves (IC₅₀ = 176.92μg/ml). From the results it can be concluded that stem and leaves of Ipomoea aquatica had similar antioxidants activity.

Keywords: Ipomoea aquatica, antioxidant, DPPH Assay, Scavenging activity, phenolic, flavonoid