Comparative Study of Antioxidant Activities of the Leaves and Stem of Ipomoea aquatica 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