In vitro antioxidant and anti-diabetic activity of milk yam (Ipomoea digitata l.) tubers

Abstract

Milk yam (Ipomoea digitata L.) tubers are medicinal having several proven pharmacological properties. In this study, milk yam rooted cuttings were raised in polybags and pharmacological properties viz., in vitro antioxidant activity (DPPH radical scavenging activity, nitric oxide radical scavenging activity and reducing power) and in vitro anti-diabetic activity (Alpha amalyse inhibition assay) of immature (six months after planting), optimally mature (21 months after planting) and over mature (36 months after planting) tubers were assessed. Pharmacological properties of milk yam tubers found to vary with maturity. DPPH radical scavenging activity and nitric oxide radical scavenging activity of optimally mature milk yam tubers (21 MAP) recorded least IC50 values, 1040.00 µg/ ml and 355.00 µg/ ml respectively. Reducing power of optimally mature milk yam tubers observed as absorbance at 400 µg/ ml concentration was 0.118 nm. Ethanolic extract of optimally mature tubers recorded superior in vitro anti-diabetic activity (99.20 per cent). This study revealed that, for better pharmacological properties milk yam tubers have to be harvested by 21 months after planting only.