Magnolin is the most active ingredient in the herb Magnolia fargesii, which has been traditionally used in oriental medicine to treat headaches and nasal congestion. Recent researches demonstrate that Magnolin inhibits cancer cell migration and invasion.

This study used cell culture and the BALB/c nu/nu mouse xenograft model to investigate whether or not magnolin can inhibit the growth of PC3 and Du145 prostate cancer cells. MTT assay and flow cytometry were performed to estimate the proliferation, cycle, and apoptosis of the cells in vitro. Clone formation assay was also conducted. In the animal study, Ki-67 immunostaining and TUNEL assay were carried out to evaluate cell proliferation and apoptosis, respectively. To elucidate the possible mechanism by which magnolin attenuates prostate cancer cell growth, we estimated the expression levels of Akt/p-Akt, P53, P21, BCL-2, and cleaved Caspase3 by using Western blot 48h after magnolin-treatment of the cells.

Magnolin inhibited the proliferation and viability of the tumor cells by triggering cell cycle arrest via P53/P21 activation and inducing apoptosis in vitro and in vivo. Magnolin downregulated the phosphorylation of Akt protein kinase and upregulated cleaved Caspase3 during anti-proliferation and pro-apoptosis.

Magnolin may be a novel medicine for prostate cancer therapy.