A Lectin with Larvicidal Potential from the Fresh Leaves of Agelanthus brunneus (Engl.) Van Tiegh Loranthaceae

Aims: This study reports the physicochemical properties and larvicidal activities of a lectin isolated from the leaves of Agelanthus brunneus (Engl.) Van Tiegh with a view to exploring its potential application and usage.

Methods: The fresh leaves were homogenized with PBS and partial purification of the lectin was carried out by gel filtration on Sephadex G-75; physicochemical and biological properties of the purified lectin were also determined.

Results: The results revealed that lectin from A. brunneus leaves agglutinated non-specifically the red blood cells of the human ABO system as well as the rabbit erythrocytes and the haemagglutinating activity was inhibited by lactose. The lectin was stable over a broad temperature range (up to 70°C) and maximum activity was observed in the 3 - 7 pH range. EDTA had no inhibitory effect on its haemagglutinating activity. Lectin activity was found to be maximal when photosynthesis was at its peak. The lectin was found to be toxic on Culex quinquefasciatus (Say) with LC50 of 0.24 mg/ml.

Conclusion: The findings of the present study clearly revealed that the lactose-specific lectin from A. brunneus was an effective larvicidal agent against C. quinquefasciatus mosquito larvae and could be developed as biological control agent.