Abstract

The phytochemical composition, antioxidant and antidiabetic activities of ethanol extract of the stem, leaves and tuber of A. difformis, were studied. The antioxidant contents were determined using Ferric-ion Reducing Antioxidant Power (FRAP), Total Antioxidant Capacity (TAC), and Trolox Equivalent Absorbance Capacity (TEAC) assays. The in vitro antidiabetic activities were determined spectrophotometrically. by measuring the inhibition of α-amylase and α-glucosidase enzymes. The phytochemical results showed that the stem, leaves and tuber of A. difformis contain alkaloids, tannins, saponins, and flavonoids. Steroid was found only in the tuber while cardiac glycosides, anthraquinones and phlobatannins were absent in all the samples. The leaves, stem and tuber of A. difformis have antioxidant potentials with the highest antioxidant potential present in the tuber; FRAP (291.62 ± 6.45 mg/100g), TAC (381.00 ± 7.22 mg/100g), and TEAC (59.78 ± 6.50 mg/60g). The antidiabetic results revealed that the stem, leaves and tuber of A. difformis inhibited α-amylase and α-glucosidase enzymes in vitro but the stem possessed the highest antidiabetic potentials. This research provides evidence that A. difformis extracts could be a potential source of natural antioxidant and antidiabetic that may be used to manage oxidative stress and diabetes. The results from this research further indicated that the tuber would be a better antioxidant, while the stem may be more useful as an antidiabetic agent. The phytochemicals present support the extensive ethno-medicinal usage of the leaves, stem and tuber of A. difformis.