Toxic Components of Auricularia polytricha

To find biologically active components of the higher fungi of Korea, the carpophores of Auricularia polytricha, a well-known edible mushroom, were extracted with 0.14 M NaCl solution. The extract was successively fractionated by adding ammonium sulfate at various concentrations, and the respective precipitates were separated by centrifugation, then dialyzed and freeze-dried. When a does of 60 mg/kg of each was injected i.p. into ICR mice, the fraction which precipitated at 20% ammonium sulfate showed the highest toxicity, killing seven out of seven mice within two days. The fraction obtained at 40% ammonium sulfate showed the second highest toxicity. The two fractions were named auritoxin I and II after the genus name. However, they Nere shown to have nearly identical composition by physicochemical and 6.8% protein. The polysaccharide moiety was found to have 12.3% $\alpha$-linkage and 87.7% $\beta$-linkage and to be a heteromannoglucan consisting of 45.1% glucose, 435 mannose and 11.0% xylose. The protein moiety contained ten amino adids. The molecular weight of the toxin was $1.5\times10^6$ dalton by Sepharose CL-4B gel filtration. The modian lethal doses of auritoxin in mice were 56.4, 157.2 and 454.6 mg/kg by i.p., s.c. and p.o.administrations, respectively. The signs of intrxication were convulsion during the first 30 minutes after the injection, coma or sleeping within an hour, termor, lacrimation, nasal bleeding congestion, and death in 24 hours. Smong the various organs, the spleen was found to be enlarged remarkably. Human platelet aggregation was inhibited by the addition of auritoxin. The activity of malic dehydrogenase in vitro was inhibited by the toxin.