IL6 and cervical cancer: To investigate whether ZO essential oil can suppress the production of interleukin 6 (IL-6), which is one of the specific cytokine markers in HeLa cells responsible for cervical cancer development and progression [18,19,20,21,22], ELISA was performed to measure the amount of IL-6 in the culture media of HeLa cells treated with ZO essential oil at different dilutions for 24 h.