Identification of potential therapeutic role of thymus capitatus essential oil using cellular imaging

Abstract

Plant derived natural products can provide promising anti-cancer activity and can support the development of novel anti-cancer treatment strategies as cytotoxic activity towards cancer cells was observed in the recent studies in which different human cancer cell lines were exposed to plant essential oils. In our study, thyme (Thymus capitatus) essential oil analyzed by GC and GC/MS showed high content of thymol, p-cymene, carcacrol and γ-terpinene representing 62.3%, 10.9%, 6.7% and 5.1% of total oil respectively. It was tested for its potential therapeutic role by using neoplastic transformed human telomerase reverse transcriptase (hTERT) immortalized mesenchymal stem cells (hMSC- telo1) and a tumorigenic cell line; human telomerase reverse transcriptase immortalized mesenchymal stem cells which are irradiated with 2.5 Gy of gamma-rays. The hMSC- telo1 and irradiated hMSC- telo1cells were exposed to increasing concentrations of thyme essential oil in order to investigate the effects of different concentrations of thyme essential oil on the hMSC- telo1 and irradiated hMSC- telo1cells and to identify any cellular response of thyme essential oil towards these cell lines. The hMSC- telo1and irradiated hMSC- telo1cells were treated with 0.5% (v/v), 1% (v/v) and 2% (v/v) thyme essential oil. Cellular response of hMSC- telo1 and irradiated hMSC- telo1cells to thyme essential oil was evaluated for all three concentrations at different time points (0 h, 2 h, 4 h, 24 h, 72 h and 120 h) by investigating proliferation rate, viability and morphology. Our results demonstrated that there was significant effect of all three concentrations used on hMSC- telo1and irradiated hMSC- telo1cells; particularly the effect was higher on the cells treated with 0.5% (v/v) thyme essential oil. Furthermore, when cellular response at different time points were compared, it was shown that exposure time to thyme essential oil is highly important for cellular viability.