Crude extract was prepared from the sea anemone, Bunodosoma cavernata.
. The protein content of the extract was estimated to be 0.53 mg prote
in/ml. The extract was standardized based on the percentage inhibition
of histamine-induced contraction of the guinea pig ileum, to determin
e the biological unit of activity (AU) of the extract. As extracts pre
pared on different occasions lost potency on storage, the stability of
the extract was also investigated. Extracts prepared from fresh anima
ls were about 15% more potent than those prepared from freeze-dried an
imals. However, freeze-dried animal extracts maintained their potency
for about 6 months under storage at -20 degrees C. Lethality studies g
ave an LD50 of 40 mu g protein/kg mice i.p. Also, the crude el;tract d
ose-dependently hemolyzed human erythrocytes at room temperature. This
activity was favoured by higher temperatures, which peaked at about 6
0 degrees C, and by pH in the alkaline range. We conclude that the cru
de extract from B. cavernata, though highly toxic, may also contain so
me biologically active agents which include a haemolytic factor and an
tihistamine(s), as indicated by its histamine-blocking action, (C) 199
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