Phytochemical Study and Anti-nutritional Factors in Stems of Dioscorea praehensilis Benth (Dioscoreaceae)

Abstract

The aim of this research was to find and assay phytochemical compounds and various biological macromolecules of the tender stems of Dioscorea praehensilis benth and evaluate their antioxidant activity and to compare the content of oxalates and cyanogenetic glucosides between raw and cooked tender stems. The plant collection and identification, phytochemical evaluation: phytochemical screening, preliminary (qualitative) analyses and in vitro assays. Phytochemical screening was performed by qualitative methods. The estimation of the content of secondary metabolites was evaluated by spectrophotometry-UV. Antioxidant activity was evaluated using the ABTS and DPPH assays and preliminary composition by the gravimetric method. The results obtained show that the stems of Dioscorea praehensilis are devoid of certain important chemical groups, the flavonoids were not detected and they were rich in total polyphenols (17.22 ± 0.16), tannins (19.32 ± 0.52) and anthocyanins (25.22 ± 0.04). Our extracts showed a lower antioxidant activity than that of positive controls. The samples are rich in carbohydrates and fiber, with low levels of proteins, lipids and ash. Dioscorea praehensilis has a high toxicity in HCN, but after a good cooking of about 1 hour, 99.97% of the cyanide are eliminated and does not have many oxalates. The results obtained show that Dioscorea praehensilis has a high dietary value and can therefore be used as a nutritive food.