Further insight into the bioactivity of the freshwater sponge Ochridaspongia rotunda

Context: Bioprospection has become a dynamic scientific field that explores novel possibilities for the implementation of natural products in medicine and pharmacy. Compared to marine species from all kingdoms, freshwater species have been highly neglected. Objective: This work focuses on the screening of acetylcholinesterase inhibitory (AChE) and mutagenic activities of the acetone extract (obtained by maceration) of the freshwater sponge Ochridaspongia rotunda Arndt (Malawispongiidae) in vitro. Materials and methods: AChE inhibitory activity was evaluated both in liquid (five different concentrations of the extract, from 1 to 100 μg/mL) and in solid (seven different concentrations of the extract, from 0.5 to 10.0 μg) by methods well described in literature, while mutagenicity was estimated using the Ames test (four different concentrations of the extract, from 0.106 to 1.328 mg/plate). Results:Ochridaspongia rotunda acetone extract exhibited promising AChE inhibitory activity in a dose-dependent manner both in liquid (IC(50) 23.07 μg/mL) and in solid (1.50 μg). Furthermore, the Ames test revealed no sign of mutagenicity at any concentration tested. Its FTIR spectrum coupled with the positive Liebermann?Burchard, Salkowski and Zak color reactions (tests) indicated the presence of sterol compounds. Discussion and conclusion: The screened extract may inspire a search for novel anticholinesterase therapeutic agent(s) potentially used in the treatment of Alzheimer's disease. Further research will be directed toward its detailed chemical analysis along with addressing the issue of a real producer of the natural product(s) responsible for the AChE activity observed.