Cytotoxic Effects of Essential Oils of Some Iranian Citrus Peels

E about 98.4% and 98.8% of content of c. limon and c. sinensisthere have been efforts to overcome the problem in treatment of cancer using medicinalplants. it has been shown that citrus essential oil of contains different terpens with antitumoractivities. in this study we sought to determine the cytotoxicity of essential oils of iraniancitrus limon (l.), c. medica (l.), c. sinsensis (l.) peels on cancer cell lines. essential oilswere prepared by hydrodistilation and characterized by gc-ms. the effects of c. limon (5-40(mu)g/ml), c. medica and c. sinensis (0.25-10 (mu)g/ml) on two human tumor cell lines (mcf-7and hela) were determined. different concentrations of essential oils were added to culturedcells and incubated for 72 h. cell survival was evaluated using the mtt-based cytotoxicityassay. while limonene comprise about 98.4% and 98.8% of content of c. limon and c. sinensisessential oils respectively, its' percentage in c. medica was only 56.6%. in c. medica therewas a considerable amount of (beta)-pinene, (gamma)-terpinene, (alpha)-terpinolene and trans-(alpha)-bergamotene.ic50 of essential oil for mcf-7 cell line was: c. limon (almost equal) 10 (my)g/ml, c. medica(almost equal) i (mu)g/ml andc. sinensis (almost equal) 0.5 (mu)g/ml. for hela cell line ic50 was: c. limon(almost equal) 17 (mu)g/ml, c. medica (almost equal) 1(mu)g/ml and c. sinensis (almost equal) 3 (mu)g/ml. our findings revealed that c. limon and c. sinensis had agreater cytotoxic effect on mcf-7 than that on hela cells. also, comparing ic50, our findingsindicated that c. medica and c. sinensis were more cytotoxic than c. limon. comparison of theessential oil component ofc. limon with c. medica, shows the presence of b-pinene (16.3%),a-terpineol (11.3%), (gamma)-terpinene (4.4%), and trans- u-bergamotene (3.4%), which were notfound in c. limon. hence, it could be concluded that these components may have greatercytotoxic effects or they may also have synergistic effects with limonene.