Groups of 20 females Ha/ICR mice were initiated with 25 micrograms 7,12-dimethylbenz[a]
anthracene (DMBA) and promoted one week later with topical treatments three times per week of 5 micrograms
phorbol myristate acetate (PMA) and/or
onion oil or
garlic oil. Promotion was continued for 49 weeks in most experiments. Promotion was continued for 60 weeks in the experiment that evaluated the effect of time intervals between PMA and
garlic oil. All experiments were conducted with 0.2 ml
acetone solutions of agents.
Onion oil, but not
garlic oil, was a weak promoter in mouse skin. A 1-mg dose produced five
papillomas in three mice and one
carcinoma in 330 days (18 survivors). The 10-mg dose was more effective; it produced cumulative yields of 56
papillomas in 14 mice and 7
carcinomas in 4 mice in 345 days (14 survivors).
Onion oil is neither an initiator nor a whole
carcinogen. The effects of intervals between PMA and a 1-mg dose of onion or
garlic oil were determined. These intervals were -2 hrs, -1 hr, -0.5 hr, +0.5 hr, +1 hr, and +2 hrs with respect to time of PMA application. Maximal inhibition of
papillomas by
onion oil was observed at the +0.5-hr interval and was similar to that previously reported.
Garlic oil is not a promoter. It inhibited
papillomas at the +0.5-hr, +1.0-hr, and +2.0-hr intervals but did not appear to affect
carcinoma production.