Natural extracts from such as essential oils can help to prevent some side effects. Essential oils and their compounds have potential to be valuable resources in the production of new drugs useful against human diseases. The main purpose of using essential oils for this treatment is to prevent the side effects caused by other traditional therapies.

Our study was conducted to investigate the anticancer activity and total phenolic content of essential olis extracted from Rosmarinus officinalis, Azadirachta indica, Syzygium aromaticum and Cymbopogon nardus. The activity of these oils was tested on breast cancer cell line (MCF-7), leukemia cell line (K-562) and cervical cancer cell line (HeLa). The anti cancer activity was determined using MTT-[3-(4,5- Dimethlthiazol-2-yl)-2,5- Diphenyl tetrazolium bromide] assay. The total phenolic content was determined by using FC (Folin-ciocalteu) assay.

Among the four essential oils investigated in the present study viz., Clove, Citronella, Rosemary and Neem essential oils, each exhibited the cytotoxic activities towards MCF-7, K-562 and HeLa human tumor cell lines. On the basis of our results, Clove oil showed greater degree of cytotoxic activity on the K-562 cell line, Citronella oil showed more cytotoxic activity on MCF-7 cell line and Neem oil showed higher cytotoxic activity on HeLa cell line. On the basis of result of F-C assay, Clove oil showed greater percentage of phenolic viz., 45%.