Objective: Phytoestrogens have been reported to exhibit antiproliferation to human breast cancer cells in vitro. We tested the phytoestrogen-rich, Pueraria mirifica against rat breast cancer induction in vivo.
Methods: The weanling female Spargue-Dawley rats were pretreated with P. mirifica tuberous powder at a dosage of 0, 10, 100 and 1000 mg/kg BW/day for four consecutive weeks. Mammary tumor development was then induced with a single dose of 7,12-DMBA, 80 mg/kg BW, followed by a weekly examination for size and multiplicity of mammary tumors for 20 weeks and finally a necropsy. Mammary tissues were investigated for the virulence of tumor and also monoclonal antibody stained against ERalpha and ERbeta.
Results: Pretreatment of 1000 mg/(kgBWday) of P. mirifica tuberous powder resulted in decreasing of the virulence of rat tumor development. The mammary tumor tissues exhibited lower profile of ERalpha and ERbeta as well as ERalpha/ERbeta.
Conclusion: P. mirifica exhibited prevention of 7,12-DMBA-induced rat mammary tumors, with a proposed mechanism of strong competitive binding of its phytoestrogens to ERalpha and/or synthesis suppressor of ERalpha.