Chemical composition and biological activities of Metania and Drulia (Metaniidae) freshwater sponges from Amazonia.

Sponges from freshwater environments, unlike marine's, are poorly known producers of natural compounds with medicinal purposes. Amazonian sponges produce massive large specimens and are widely spread, taxonomically diverse and their metabolites could represent a new frontier on unusual natural products to treat diseases such as Alzheimer's and Malaria. Species of Metania and Drulia (Metaniidae) genera are major contributors to the fauna of Amazonian freshwater sponges. Methanolic extracts from several species from these genera had their inhibitory activities evaluated in vitro, for parasite Plasmodium falciparum and acetyl and butyrylcholinesterase enzymes (AChE and BChE). All extracts were able to inhibit AChE, although no activity was observed towards BChE. Drulia uruguayensis extract was the most potent, inhibiting AChE with IC50=1.04 mg/mL. For antiplasmodial activity, all species showed inhibition to P. falciparum, but Metania reticulata being the most efficient with IC50=2.7 mu g/mL. Mass spectrometry analyses evidenced the presence of fatty acids and sterols in active extracts.