STRUCTURAL CHARACTERISATION OF AN IMMUNOMODULATING POLYSACCHARIDE ISOLATED FROM AQUEOUS EXTRACT OF PLEUROTUS FLORIDA FRUIT-BODIES

The water-soluble glucan was obtained from Pleurotus florida fruit bodies by hot water extraction, ethanol precipitation, DEAE cellulose dialysis and Sephadex G-75 gel filtration. The structural information of the glucan was achieved by chemical (hydrolysis, methylation, periodate oxidation) and spectroscopic (¹H and ¹³C) analyses, indicated a repeating unit built up of (1→6)-linked D-glucose. The following structure has been determined for the repeating unit: →6)-α-D-Glcp-(1→ This fraction exhibited significant macrophage activity through the release of nitric oxide     

Activity of Praziquantel Enantiomers and Main Metabolites against Schistosoma mansoni

A racemic mixture of R and S enantiomers of praziquantel (PZQ) is currently the treatment of choice for schistosomiasis. Though the S enantiomer and the metabolites are presumed to contribute only a little to the activity of the drug, in-depth side-by-side studies are lacking. The aim of this study was to investigate the in vitro activities of PZQ and its main metabolites, namely, R- and S-cis- and R- and S-trans-4′-hydroxypraziquantel, against adult worms and newly transformed schistosomula (NTS). Additionally, we explored the in vivo activity and hepatic shift (i.e., the migration of the worms to the liver) produced by each PZQ enantiomer in mice. Fifty percent inhibitory concentrations of R-PZQ, S-PZQ, and R-trans- and R-cis-4′-hydroxypraziquantel of 0.02, 5.85, 4.08, and 2.42 μg/ml, respectively, for adult S. mansoni were determined in vitro. S-trans- and S-cis-4′-hydroxypraziquantel were not active at 100 μg/ml. These results are consistent with microcalorimetry data and studies with NTS. In vivo, single 400-mg/kg oral doses of R-PZQ and S-PZQ achieved worm burden reductions of 100 and 19%, respectively. Moreover, worms treated in vivo with S-PZQ displayed an only transient hepatic shift and returned to the mesenteric veins within 24 h. Our data confirm that R-PZQ is the main effector molecule, while S-PZQ and the metabolites do not play a significant role in the antischistosomal properties of PZQ.