Inhibition of experimental murine tumors by MT81, a new mycotoxin from Penicillium nigricans.

Effects of a new mycotoxin MT81 obtained from the fungal strain Penicillium nigricans on the growth of two transplantable murine tumors and the life span of the hosts were studied. Remarkable decrease in tumor volume and viable tumor cell count was found in both the tumors. Antitumor effect of the compound was more pronounced in Sarcoma 180 (S180) than in Ehrlich ascites carcinoma (EAC). The tumor-inhibitory effect was also manifested by the reduction in mitotic activity and appearance of membrane blebbing and intracytoplasmic vacuoles in the treated tumor cells. MT81 treatment prolonged the life span of the EAC tumor host by 78% and more than 100% in S180 bearing mice. Tumor inhibition by MT81 was followed by improvements in hemoglobin, RBC values and bone marrow cellularity. Thus the results suggest that MT81 has significant antitumor property against experimental murine tumors and it does not adversely affect the hematological profile of the hosts.