ACTIVITY OF Stryphnodendron polyphyllum, A PLANT FROM THE BRAZILIAN SAVANNAH, AGAINST HEMOCYTES OF Biomphalaria glabrata, AN INTERMEDIATE HOST OF Schistosoma mansoni

Abstract

The snail Biomphalaria glabrata acts as an intermediate host to Schistosoma mansoni, an endemic parasite in several countries. B. glabrata hemocytes are related to its defense against infection by trematodes, including S. mansoni. In the present paper, the activity of molluscicidal substances such as the tannic acid extracts of Stryphnodendron polyphyllum, a plant from the Brazilian Savannah, on the morphology and number of B. glabrata hemocytes was evaluated. The bark and leaf extracts of S. polyphyllum were diluted in dechlorinated water and groups of snails were exposed to 25 and 50 mg.L-1 concentrations of the extracts, as well as, to tannic acid during 24h. Subsequently, hemolymph was removed from the pericardic region. Hemocyte subpopulations were detected and classified as small (5.0 – 6.9 ?m), medium (7.0 – 8.9?m), large (9.0 – 12.0?m) and giant (over 12?m), the latter
being a novel classification. The extracts stimulated an increase in the number of hemocyte cells in the hemolymph. This is understood as a defense mechanism against toxic substances such as tannic acid, present in high levels in both tested extracts. Hemocytes showed vacuoles in the cytoplasm due to the presence of such substances, which are signs of cellular death due to apoptosis. We conclude that the extracts are highly effective against B. glabrata, recommending further biological impact studies aiming its use as a natural molluscicide.