Objectives:
In this research, Dioscorea preussii root tuber haemagglutinin was purified and its physicochemical properties determined. The antioxidative prowess and anti-haemolytic activities of the haemagglutinin were also investigated.
Material and Methods:
Hemagglutinating assay was used to detect the presence of lectin in the Phosphate Buffer Saline (PBS) extract of the D. preussii root tuber. The lectin was purified using ammonium sulphate fractionation and molecular sieve chromatography. Optimum pH and temperature were determined. So also, antioxidant activity was assessed using DPPH radical scavenging, metal chelating, FRAP and lipid peroxidation inhibition assays. Red blood cells subjected to oxidative damage caused by H2O2 was employed to evaluate its antihemolytic ability.
Results:
Starch inhibited the haemagglutinating activity of the hemagglutinin. Dioscorea preussii haemagglutinin (DPH) maintained full haemagglutinating activity from 30 ºC to 60 ºC and pH 5-13. EDTA had no effect on the haemagglutinating activity of the haemagglutinin. All the denaturing agents (Guanidine-HCl, Urea and β-Mercaptoethanol) reduced the haemagglutinating activity of the haemagglutinin to different degrees. The haemagglutinin scavenged DPPH radical and chelated iron metal with IC50 of 0.727 ± 0.035 mg/ml and 0.583 ± 0.078 mg/ml respectively, while the FRAP assay showed that it contains 76 mg of ascorbic acid equivalent per g of the purified haemagglutinin. In absence of hemolytic agent, minimal haemolysis was recorded but the hemagglutinin could not protect the cell membrane in the presence oxidative agents. Although, at lower concentration tested, the hemagglutinin shows positivity in membrane integrity protection.
Conclusion:
The study provides information on the antioxidant properties of D. preussii root tuber hemagglutinin as well as its cell membrane protective ability. The lectin is a starch-binding which make it a novel lectin.
Keywords: Dioscorea preussii, hemagglutinin, antioxidant, anti-haemolytic, lectin