Protective effect of tenuazonic acid against dimethyl benz(a)antracene-induced skin carcinogenesis in mice.

Anticarcinogenic potential of tenuazonic acid (TA), a mycotoxin isolated from a fungus, Alternaria alternata, on skin tumorigenesis induced by 7,12-dimethyl benz(a) antracene (DMBA) was investigated. Female Swiss albino mice were exposed topically to 100 nmole of DMBA twice weekly for 20 weeks. Another group of animals was treated with 250 microg TA in acetone daily for a period of 1 week, followed by the same dose of TA prior to every application of DMBA. At the end of 14 weeks, all the animals in the group that was exposed to DMBA alone developed tumors, while 40% of the animals in TA-treated group were found to be tumor free. After 20 weeks, there was no further increase in the number of tumor-bearing animals. Results indicated that prior application of TA significantly delayed the onset of tumorigenesis and also reduced the cumulative number of tumors per tumor-bearing animals. The present studies reveal the antitumor and protective potential of TA against polycyclic aromatic hydrocarbon induced skin carcinogenesis.