Partial Purification, Complete and Incomplete Agglutinins Detection, Agglutination Properties and Standardization of Some Tropical Euphorbiaceae Plant Lectins

Euphorbiaceae is a large family of flowering plants with numerous genera and species that occurs mainly in the tropics including the large variety that occurs in tropical Africa. Lectins are a heterogeneous class of carbohydrate-binding proteins of non-immune origin that specifically and reversibly recognize sugars or glycoconjugates without enzymatic modification. They play critical roles in cell–cell communication and molecular recognition, making them valuable in medical diagnostic applications. A total of Six (6) species of local Euphorbiaceae plants viz, Acalypha torta, Euphorbia milli, Codiaeum variegatum, Ricinus communis, Tetracarpidium conophorum, and Manihot esculenta were collected, authenticated at Botany Department of Nnamdi Azikiwe University, Awka and their crude extracts obtained. Partial purifications were conducted on these extracts in two steps: Dialysis and Silica gel chromatography techniques. The crude and partially purified extracts were subjected to haemagglutination tests but the rest of the investigations viz, Direct and Indirect Agglutinins Detection, Agglutination Properties, and Standardization were performed using the partially purified extracts.  Five (5) of the six (6) plants extracts except that of the Manihot esculenta agglutinated pooled washed human ABO cells. Agglutination properties of the lectins were determined by carrying out Protein electrophoresis in Barbitone buffer pH 8.6 on each of the extracts using human serum with distinct and characteristic globulin bands of Albumin (A), Alpha-1 (α₁), Alpha-2 (α₂), Beta (β) and Gamma (γ) as control. A. torta showed an albumin and slow gamma bands. C. variegatum and E. milli extracts gave no detectable bands. On the other hand, R. communis gave Gamma (γ), Alpha-1 (α₁), and Alpha-2 (α₂) globulin bands while T. conophorum exhibited Gamma (γ), Alpha-2 (α₂), and Beta (β) bands. The extract of M. esculenta gave no Gamma (γ) but only Alpha-1 (α₁) globulin band. Hence, these band patterns explain why the extracts with lectinic properties agglutinate human ABO cells while that of M. esculenta without lectinic activities does not. A. torta, C. variegatum and T. conophorum lectins were standardized because they cross reacted with the ABO cells in varying strengths. Lectins from A. torta designated anti-H At show specificity with O cells only at an appropriate dilution of 1 in 64 while lectins from C. variegatum designated Anti-A Cv and T. conophorum (Anti-B Tc) were found to be specific for A and B cells at titres of 16 and 128 respectively. This study has succeeded in demonstrating the partial purification, complete agglutinins detection, agglutination properties and standardization of some tropical Euphorbiaceae plants lectins, showing their potential usefulness in diagnostic and biotechnological applications.