STELLA LOIZOU¹, ZOI PAPOUTSI², NIKOLAS FOKIALAKIS³, ELEFTHERIOS KALPOUTZAKIS³ and PARASKEVI MOUTSATSOU²

¹Department of Life and Health Sciences, University of Nicosia, Cyprus, ²Department of Biological Chemistry, Medical School, University of Athens, Greece, ³Department of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmacy, University of Athens, Greece

Greek flora is very rich in aromatic plants among which are Origanum species, widely consumed herbs that belong to Lamiaceae family and are abundant in phenolic compounds (1, 2).

In this study, we examined the ability of the extracts (dichloromethanic, methanolic, aqueous) from Origanum dictamnus, Origanum scabrum and Origanum microphyllum of Greek origin, to modulate cell viability of MCF-7 and MDA (breast), Ishikawa (endometrial) and PC-3 (prostate) cancer cells, by use of MTT assay. Ishikawa, MDA and PC-3 cells showed no response to all Origanum extracts tested. The viability of MCF-7 cells showed a small but significant increase to methanolic extracts.

Furthermore, we evaluated the potential of methanolic extracts to influence the activity of estrogen receptor (ER) in MCF-7 cells transfected with an estrogen response element (ERE)-driven luciferase (Luc) reporter gene. O. dictamnus and O.scabrum extracts, in absence and in presence of 17β-estradiol (E2), reduced significantly the luciferase activity. O.microphyllum methanolic extract, when alone, increased the basal luciferase activity, whereas its coexistence with estradiol inhibited significantly the E2-stimulated gene induction. Summarising, the methanolic extracts of the three Origanum species modulate the cellular growth and estrogenic/antiestrogenic potency in MCF-7 cells.

Our study indicates that the methanolic extracts of the three Origanum species examined contain phytochemicals that have the potential to modulate cellular growth and estrogen dependent genes in breast cancer cells. The specific phytochemicals responsible for the estrogenic/antiestrogenic actions of Origanum methanolic extracts may be of potential biological importance in the estrogen dependent breast cancer and remain to be elucidated. Finally, given that the in vitro test systems are not able to predict the action of substances in the whole organism; further in vivo studies (3, 4) are warranted to understand the role of Origanum as a dietary substance and its impact on human health.

References List

1. Aligiannis N, Kalpoutzakis E, Mitaku S, Chinou IB: Composition and antimicrobial activity of the essential oils of two Origanum species. J Agric Food Chem 49: 4168-4170, 2001.
2. Economakis C, Karioti A, Skaltsa H, Perdetzoglou D, Demetzos C: Effect of solution conductivity on the volatile constituents of Origanum dictamnus L in nutrient film culture. J Agric Food Chem 53: 1656-1660, 2005.
3. Kazuhiro S, Kazuhiro G, Atsusi I, Yasuhiro K: Bioassay of phytoestrogen in herbal medicine used for postmenopausal disorder using transformed MCF-7 cells. Phytother Res 13: 498-503, 1999.
4. Diel P, Schmidt S, Vollmer G: In vivo test systems for the quantitative and qualitative analysis of the biological activity of phytoestrogens. J Chromatogr B 777: 191-202, 2002.