Chemical Composition, Cytotoxic, Apoptotic and Antioxidant Activities of Main Commercial Essential Oils in Palestine: A Comparative Study

Abstract

Background: Essential oils (EOs) are complex mixtures of several components gifted with a wide array of biological activities. The present research was designed to evaluate whether commercial essential oils could be effective by examining their in vitro antioxidant, cytotoxic, and apoptotic properties of nine commercially available EOs in Palestine, namely, African rue, basil, chamomile, fennel, fenugreek, ginger, spearmint, sage, and thyme, and to assure their effective use. Methods: The cytotoxic activity was determined using HT29-19(A) non-muco secreting and HT29-muco secreting (MS) cell lines. MTT, and trypan blue tests, and DPPH radical scavenging have also been assayed on the studied EOs. Results: In this work chamomile oil showed the lowest IC₅₀ at the content of 60 µL/mL, while all other EOs reached such a decrease when 70-80 µL/mL was used on HT-29 (MS) cell lines. In HT-29 19(A) cells, 50% of viability was obtained when 80 µL/mL of ginger and African rue was used, while all other EOs needed more than 80 µL/mL to reach such a decline in viability. Otherwise, an MTT assay on HT-29 (MS) displayed ginger EO with the lowest IC₅₀, followed by African rue and sage, with 40, 48 and 53 µL/mL, respectively. Otherwise, for the rest of the EOs, the IC₅₀ was obtained by assaying around 80 µL/mL. Ginger showed the lowest IC₅₀ with 60 µL/mL and thyme was the highest with 77 µL/mL when HT-29 19(A) cells were used. Conclusion: The most active EOs were found to be ginger, chamomile oil, and African rue. In general, the results demonstrate that most commercial EOs tested in this work possess low, or no biological activities; this may be due to processing, storage conditions, and handling or other reasons, which may cause losses in the biological and pharmacological properties that endemically exist in the Eos; hence, more investigation is still required on commercial EOs before they are recommended to the public.

Keywords: anti-cancer activity; antioxidants; apoptosis; cell lines; cytotoxicity; essential oils (EOs).

Figure 1

Viability percentages of: (a) HT29-19(A) non-muco secreting and (b) HT29-muco secreting (MS) cell lines treated for 48 h with EOs.

Figure 2

Effect of ginger oil on the HT-29 (MS) cell line as observed under the microscope. × 400 (a), represents cells at time 0 min; (b–d) cell at 30 min intervals after ginger oil addition.

Figure 3

MTT assay using cell lines treated with EOs for 48 h: (a) IC₅₀ on HT-29 19(A); (b) IC₅₀ on HT-29 (MS).