In vitro tests to evaluate potential biological activity in natural substances.

The biological activity of polysaccharides from the mycelia of 40 Basidiomycetes was studied using an uncommon toxicity test technique, the planaria bioassay, and the better known potato disk bioassay. The results showed the utility of this duo of 'in vitro' tests as a preliminary screening of the toxicity of substances that are present in aqueous fungal extracts.