Highlights Purification of Moringa oleifera seed lectin (MoL) was achieved by ammonium sulfate precipitation and size exclusion chromatography MoL hemagglutinating activity was thermostable up to 90°C, within pH 2-4 and moderately inhibited by sucrose and fructose Traces of Ca2+, Mg2+, and Na+ was detected in MoL, and modification of arginine and tryptophan residues affected the hemagglutinating activity Hemolytic (membrane-perturbing) activity of MoL was potentiated in mildly acidic pH, and dependent on concentration, temperature, pH, and time of incubation.

This study investigated the larvicidal activity on Culex quinquefasciatus of lectin purified from fresh fruiting bodies of woodland mushroom, Agaricus semotus. A. semotus lectin (ASL) was purified via ion-exchange chromatography on DEAE-cellulose A-25 and size exclusion chromatography on Sephadex G-100 matrix. Molecular weight (16.6 kDa) was estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The effects of temperature, pH, metal chelation- and larvicidal activity of ASL were also investigated. The ASL indifferently agglutinated the erythrocytes of the human ABO blood system and was stable at acidic pH and below 50 °C whereas 66% of its activity was lost at 60 °C with complete inactivation at 70 °C. ASL is a metalloprotein requiring barium ion as chelation of metals by 50 mM EDTA rendered the lectin inactive, while the addition of BaCl2, among other metal salts, restored the activity. ASL showed larvicidal activity against C. quinquefasciatus larvae after 24 h with a mortality of 5 and 95% at 5 and 25 mg/mL respectively, and LC50 of 13.80 mg/mL. This study concluded that purified A. semotus lectin showed impressive larvicidal activity, which could be exploited in its development as an insecticidal agent.

Erythrina senegalensis (Fabaceae) have been traditionally used in the treatment of microbial ailments, and the specific agent mediating its efficacy has been investigated in several studies. In this study, the antimicrobial activity of purified E. senegalensis lectin (ESL) was analyzed. The phylogenetic relationship of the gene encoding lectin with other legume lectins was also established to investigate their evolutionary relationship via comparative genomics. Antimicrobial activity of ESL against selected pathogenic bacteria and fungi isolates was evaluated by the agar well diffusion method, using fluconazole (1 mg/ml) and streptomycin (1 mg/ml) as positive controls for fungi and bacteria sensitivity, respectively. Potent antimicrobial activity of ESL against Erwinia carotovora, Pseudomonas aeruginosa, Klebsiella pneumonia, Staphylococcus aureus, Aspergillus niger, Penicillium camemberti, and Scopulariopsis brevicaulis was observed, with inhibition zones ranging from 18 to 24 mm. Minimum inhibitory concentrations of ESL ranged between 50 and 400 μg/ml. Primer-directed polymerase chain reaction of E. senegalensis genomic DNA detected a 465-bp lectin gene with an open reading frame encoding a 134-amino acid polypeptide. The obtained nucleotide sequence of the ESL gene shared high sequence homology: 100, 100, and 98.18% with Erythrina crista-galli, Erythrina corallodendron, and Erythrina variegata lectin genes, respectively, suggesting that the divergence of Erythrina lectins might follow species evolution. This study concluded that ESL could be used to develop lectin-based antimicrobials, which could find applications in the agricultural and health sectors.