Antibacterial Activity and Cytotoxicity of Three Lectins Purified from Drumstick (<i>Moringa oleifera</i> Lam.) Leaves

Abstract

Context: Plant materials contain glycoproteins (phytolectins) that are toxic in nature may play a key role in the control of various normal and pathological processes in living organisms and have diverse biochemical and diagnostic applications.

Objectives: Screening of three lectins SLL-1, SLL-2 and SLL-3 purified from Drumstick (Moringa oleifera Lam.) leaves for their antibacterial activities and brine shrimp lethality bioassay.

Materials and Methods: Three bioactive lectins were purified from Drumstick leaves by conventional chromatographic methods. The lectins were tested for their antibacterial activities against three pathogenic bacteria- Escherichia coli (gram-negative) Shigella dysenteriae (gram-negative) and Staphylococcus aureus (gram-positive) using the standard disc-diffusion method. Mortality of the brine shrimp naupli was assessed by hality bioassay.

Results: All the lectins showed antibacterial activity against E. coli, Sh. dysenteriae and St. aureus. They also showed cytotoxic effect in brine shrimp (Artemia salina L.) lethality bioassay. The LC₅₀ values of SLL-1, SLL-2 and SLL-3 were found to be 15.8, 17.78 and 14.12 μg/ml respectively. The experimental results revealed that SLL-3 is more cytotoxic than other lectins. The lectin SLL-3 showed lowest activity whereas SLL-1 showed highest activity against the three bacteria.

Conclusion: Results suggest that the extracts from M. oleifera leaf can be a source of natural antimicrobials with potential applications in pharmaceutical industry to control coliform bacteria.

Key words:  Drumstick; Moringa oleifera; lectins; antibacterial activity; brine shrimp; bioassay

DOI: 10.3329/jbs.v17i0.7112

J. bio-sci. 17: 89-94, 2009