Inhibition of lectin agglutination by Rawcarica papaya extracts

Abstract

The study was carried out to determine the inhibition of lectin agglutination using extracts of raw pawpaws. Lectins are hemagglutinins detected through their ability to bind sugars on the cell surface. They were extracted from jackfruit seeds and used in the hemagglutination assay. Their high concentration in the seeds was evidenced by the hemagglutination titre which was 12.Agglutination occurred in wells 1 to 7, in rows A and B of the test plate, while there was no visible agglutination in wells 8 to 10. Hemagglutination was due to interactions between multivalent lectins and sugars on membrane of red blood cells via weak intermolecular forces such as hydrogen bonds, van der Waals forces and divalent cations in lectins, which readily bind to membranes even without attractive forces. Results of hemagglutination inhibition assay showed total inhibition in the wells. The ability of raw pawpaw extracts to inhibit agglutination is explained by presence of high concentration of protease enzymes in the latex that can hydrolyse peptide bonds in the lectins making them unable to bind to RBC membrane hence causing agglutination. Raw pawpaw in addition contain antioxidants that removes free radicals produced during oxygen crisis, and aromatic amino acids that bind to haemoglobin molecule and prevent interaction between hydrophobic amino acids thus preventing agglutination. Therefore,this study has confirmed that extract from raw pawpaw can inhibit lectinagglutination of SRBCs in vitrohence could form the basis for further investigation of reversal of agglutination of sickled RBC in sickle cell patients during crisis.