Effects of essential oils of Origanum vulgare L. and Origanum majorana L. on cancer cells line BCL-1 and immune system cells

Plants from the fam. lamiaceae are the rich sources of medicinal compounds with the anticancer properties. In many studies, only the anticancer properties of these compounds have been investigated and their toxicity on the healthy cells has not been addressed. The present study was designed to evaluate and compare the toxic effects of Origanum vulgare L. and O. majorana L. essential oils on the cancer cells line BCL-1 and normal lymphocytes and macrophages under in vitro conditions. The plant samples essential oils were extracted using the hydro-distillation method and analyzed by GC and GC/MS. The cancer cells line BCL-1 and normal lymphocytes and macrophages were cultured with the various concentrations of essential oils for 24h. The viability and cells toxicity under the influence of essential oils were determined by the MTT and LDH assays. The GC/MS results showed that the two essential oils had only 12 common components. Both essential oils inhibited the growth of cancer cells line BCL-1 (O. vulgare, 47-79% and O. majorana, 30-82%) at a concentration of 0.01-1% (O. vulgare essential oil IC50: 0.01% and O. majorana essential oil IC50: 0.03%). The essential oils at the highest concentration (1%) did not decrease the immune cells viability. Also, according to the LDH test results, none of the concentrations of both essential oils had a toxic effect on the normal lymphocytes and macrophages. Overall, based on the present study results, the O. vulgare and O. majorana essential oils could be recommended as good candidates for the cancer treatment because they had no cytotoxic effect on the normal immune system cells in addition to having the strong anticancer properties.