Partial Purification, Characterization and Bacterial Agglutination Potentials of Some Tropical Euphorbiaceae Plant Lectins

Lectins are sugar-binding proteins of non-immune origin that play immense roles in recognition at the cellular and molecular levels making them useful in biomedical and biotechnological 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 Characterization using Electrophoresis technique, and Bacterial Agglutination Potentials assays were determined using only the partially purified extracts. Five (5) of the Six (6) plants extracts except that of the Manihot esculenta agglutinated separately pooled and washed human ABO cells. All agglutination reactions were direct, that is, complete in normal saline suspensions of red cells. Protein electrophoresis was carried out 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. Bacterial agglutination surveys demonstrated that A. torta and T. conophorum lectins possess strong specificity for Enterococcus faecalis, Pseudomonas aerogenosa, and Escherichia coli, indicating their potential as bacterial typing reagents. In contrast, M. esculenta, which lacked lectinic properties and gamma globulin bands, gave no agglutination reaction with any of the bacteria organism. This research has therefore succeeded in partially purifying, characterizing, and determination of bacterial agglutination potentials of some isolated tropical Euphorbiaceae plant lectins.