We evaluated deguelin and silibinin in A/J mice treated
with the tobacco-specific carcinogen benzo(a)pyrene
(BP) for their ability to inhibit pulmonary adenoma formation
and growth. Animals were treated with either
deguelin (5.0 or 10.0 mg/kg body weight, by gavage) or
silibinin at doses of 0.05% and 0.1% in the diet, approximately
10 days before a single intraperitoneal dose of
BP. We found that oral administration of deguelin reduced
tumor multiplicity by 56% and tumor load by
78%, whereas silibinin treatment at doses of 0.05%
and 0.1% in the diet did not show any significant efficacy
on either tumor multiplicity or tumor load. The result
indicates that deguelin significantly inhibits pulmonary
adenoma formation and growth in A/J mice. Finding new
and effective agents that can prevent lung cancer is
urgently needed because cancer of the lungs remains the
principal cause of cancer deaths in the United States and
because effective chemoprevention of this cancer type
remains elusive. Thus, deguelin appears to be a promising
new preventive agent for lung cancer and may be
considered for further studies in other animal models and
in clinical trials