Magnolia dealbata seeds extract exert cytotoxic and chemopreventive effects on MDA-MB231 breast cancer cells.

BACKGROUND

Cancer prevention remains a high priority for the scientific world. Magnolia dealbata Zucc (Magnoliaceae), a Mexican endemic species, is used for the empirical treatment of cancer.

OBJECTIVE

To evaluate the cytotoxic and cancer chemopreventive effects of an ethanol extract of Magnolia dealbata seeds (MDE).

METHODS

The cytotoxic effect of MDE, at concentrations ranging from 1 to 200 µg/ml, on human cancer cells and human nontumorigenic cells was evaluated using the MTT assay for 48 h. The apoptotic activities of MDE 25 μg/ml on MDA-MB231 breast cancer cells were evaluated using the TUNEL assay and the detection of caspase 3 using immunofluorescence analysis for 48 h, each. The chemopreventive effect was evaluated by administrating different doses of MDE, between 1 and 50 mg/kg, injected intraperitoneally daily into athymic mice which were implanted with MDA-MB231 cells during 28 days. The growth and weight of tumors were measured.

RESULTS

MDE showed cytotoxic effects on MDA-MB231 cells (IC₅₀ = 25 µg/ml) and exerted pro-apoptotic activities as determined by DNA fragmentation in MDA-MB231 cells. MDE 25 µg/ml also induces the activation of caspase 3 in MDA-MB231 cells. These results suggest that Magnolia dealbata may be an optimal source of the bioactive compounds: honokiol (HK) and magnolol (MG). MDE 50 mg/kg i.p. exerted chemopreventive effects by inhibiting the growth of MDA-MB231 tumor by 75% in athymic mice, compared to the control group.

CONCLUSIONS

MDE exerts cytotoxic, apoptotic and chemopreventive activities on MDA-MB231 human cancer cells.