Biochemical characterisation of lectin from Indian hyacinth plant bulbs with potential inhibitory action against human cancer cells.

This work describes purification and characterisation of a monocot mannose-specific lectin from Hyacinth bulbs. The purified lectin has a molecular mass of ∼30kDa in reducing as well as in non-reducing SDS-PAGE. In hydrodynamic studies by Dynamic Light Scattering (DLS) showed that purified lectin was monomeric in nature with a molecular size of 2.38±0.03nm. Agglutination activity of purified lectin was confirmed by rabbit erythrocytes and its agglutination activity was inhibited by d-mannose and a glycoprotein (ovalbumin). Glycoprotein nature of purified lectin was confirmed by Periodic Acid Schiff's (PAS) stain. Purified lectin showed moderate pH and thermal stability by retaining hemagglutination activity from pH 6-8 and temperature up to 60°C. It also suppressed the growth of human colon cancer cells (Caco-2) and cervical cancer cells (HeLa) with IC values of 127μg/mL and 158μg/mL respectively, after 24-h treatment. Morphological studies of treated cells (Caco-2 and HeLa) with hyacinth lectin by AO/EB dual staining indicated that purified lectin is capable of inducing apoptosis.