Total Antioxidant Capacity, Polyphenolic composition and Cytotoxicity of Three Varieties of Livingstone Potato (Rizga)

Abstract

The growing interest in the substitution of synthetic food antioxidants with natural ones in the maintenance of human health has fostered increased research on the screening of plants for the identification of antioxidants. The total antioxidant capacity and polyphenolic content of the extracts of the three varieties of rizga flour as measured by the quantities of quercetin and polyphenols present showed that all three varieties contained significant quantities of antioxidants and polyphenols. However, the total antioxidant capacity and polyphenolic composition of langaat was lower than that of beebot and riyom (P< 0.05). The phytochemical screening of the flours as determined using standard qualitative methods indicated the presence of cyanogenic glucosides, tannins and flavonoids in all the three varieties studied but beebot and riyom contained alkaloids in addition. The extracts of the 3varieties of rizga had a low cytotoxic effect on the rats studied with their LD50 higher than that of potassium dichromate used. Correlation between the total antioxidant capacity and polyphenolic composition of the 3varieties of rizga was found to be significant (R²=0.725).These findings suggest rizga to be a natural source of antioxidants and thus could be used in the treatment of ailments implicating free radicals. In addition, it’s safe for consumption.