Cytotoxic Effect of Thymus caramanicus Jalas on Human Oral Epidermoid Carcinoma KB Cells.

Identifying new chemotherapeutic agents with fewer side effects is a major concern for scientists today. Thymus caramanicus Jalas (Lamiaceae family) is one of the species of Thymus that grows wild in different regions of Iran. Traditionally, leaves of this plant are used in the treatment of diabetes, arthritis and cancer. Here was investigated the cytotoxic property of Thymus caramanicus essential oil and extract in human oral epidermoid carcinoma KB cells. Cell viability was measured by MTT and neutral red assays. The cells were exposed to different concentrations of essential oil (0.05-1 µL/mL) and extract (25-150 µg/mL) for 24 h. Doxorubicin was used as anticancer control drug. The data showed that the essential oil (IC50=0.44 µL/mL) and extract (IC50=105 µg/mL) induce potent cytotoxic property. Surprisingly, cytotoxic effects of essential oil and extract of this plant on KB cancer cells were greater than those on normal gingival HGF1-PI1 cell line. In addition, Thymus caramanicus could potentiate the effect of doxorubicin in sub-effective concentrations. The results of the present study indicate that essential oils and extracts of Thymus caramanicus have potential anti-proliferative property on KB cells and can be used as pharmaceutical case study for oral cancer treatments.