Antitumoral Effects of Melissa officinalis on Breast Cancer in Vitro and in Vivo

Background: There is a long standing interest in the identification of medicinal plants and derived naturalproducts for developing cancer therapeutics. Here we investigated the antiproliferative properties of Melissaofficinalis (MO) from Turkey on breast cancer.
Methods: MO extracts were studied for cytotoxicity againstbreast cancer cell lines (MCF-7, MDA-MB-468 and MDA-MB-231). In vitro apoptosis studies were performedby annexin V staining and flow cytometry analyses. Immunohistochemistry for Ki-67 and caspase 7 in thetumoral tissue sections of DMBA-induced mammary tumors in rats was also performed, along with TUNELassays to detect apoptotic cells. In vivo anticancer activity testing was carried out with reference to inhibitionof growth of DMBA induced mammary tumors in rats.
Results: MO showed cytotoxicity against three cancercell lines, inducing increase in Annexin-positive cells. Expression of caspase-7 protein and TUNEL positive cellswere much higher in rats treated by MO, compared with the untreated control group, while expression of Ki-67was decreased. Furthermore, in vivo studies showed that mean tumor volume inhibition ratio in MO treatedgroup was 40% compared with the untreated rats.
Conclusion: These results indicated that MO extrcts haveantitumoral potential against breast cancer.