A new cytochalasan compound, chaetoglobosin A produced by Chaetomium globosum, was studied for its toxicity to animals. By subcutaneous injection, 2 mg/kg body weight of chaetoglobosin A killed young Wistar rats acutely, and in the mouse of DDD strain, LD50 values of chaetoglobosin A were estimated 6.5 and 17.8 mg/kg for male and female, respectively. By oral administration, 400 mg/kg of chaetoglobosin A caused little adverse effect on mice and rats. Pathological examination of the mice, injected subcutaneously with 5 mg/kg of the toxin, revealed marked edema at the injection site which appeared in several hours after injection and subsided in a week. In other tissues necrosis of the thymus and spleen and degeneration of the spermatocytes in the testicles were noticeable. With characteristic cytotoxic effects like cytochalasin B, chaetoglobosin A is an interesting mycotoxin, although it may be of little significance as a food- or feed-borne toxin.
