Purification of a Seed-Derived Lectin from Medicinally Important Plant Terminalia Catappa (TC)

Abstract

Lectins represent a diverse class of carbohydrate-binding proteins distributed across plants, animals, fungi, and marine organisms. Their strong affinity for specific sugar residues enables them to participate in essential biological events, including cell signaling, immune modulation, and defense against pathogens. Among them, plant lectins have received considerable attention due to their medicinal attributes, such as antifungal, antiviral, anti-inflammatory, and antitumor activities. Harnessing these therapeutic potentials, however, requires reliable and efficient methods for their extraction and purification. In the present study, a lectin-like protein was extracted from Terminalia catappa seeds using phosphate-buffered saline (PBS) and purified through sequential ammonium sulphate precipitation, dialysis, gel filtration, and affinity chromatography. The crude extract had a protein concentration of 1.5 mg/mL, which was reduced to 0.9 mg/mL following gel filtration and 0.7 mg/mL after affinity chromatography. The appearance of a single, well-defined peak on the affinity column confirmed the homogeneity of the purified lectin and corresponded with an increase in its specific activity.