Comparative Evaluation of Purity and Antioxidant Effects of Commercial and Laboratory Essential Oils of Cinnamomum zeylancium

Abstract

Background: According to the proof of antioxidant and antibacterial effects of cinnamon essential oil, nowadays several commercial companies around the world have extracted and distributed cinnamon essential oil with one hundred percent purity. Objectives: This study has been designed to evaluate chemical composition and antioxidant activity of commercial cinnamon essential oil compared with pure essential oil obtained in laboratory. Materials and Methods: Laboratory cinnamon essential oil was extracted by hydro distillation method and the commercial essential oils were purchased from two different companies. GC/MS analyses were done to find out the chemical compositions and finally the antioxidant activity of essential oils was determined using three different methods including Fe II chelating test, Reducing power and Antiradical effect (DPPH). Results: The main components identified in laboratory cinnamon essential oil were Cinnamaldehyde (77%), Cinnamaldehyde Dimethyl Acetate (6.6%), Alpha- copaene (6%) and Delta-cadinene (3%). The result of GC/MS showed that the components of the laboratory essential oil were different from those of commercial ones, so that in the two commercial essential oils Cinnamaldehyde, trans caryophyllene, linalool and eugenol were the main components. Regarding the antioxidant activity of metal chelating test, the laboratory essential oil with the inhibitory effect of 17.1% was stronger than two commercial essential oils with the inhibitory effect of 9% and 6.2% for highest concentration (P<0.05). But laboratory essential oil was statistically weaker than commercial essential oils with the IC50 of 22449 μg/ml compared with 5708 μg/ml and 4230 μg/ml in DPPH assay, as well as absorption values of 0.15 compared with 0.2 and 0.22 for highest concentration in reducing power assay, respectively (P<0.05). Conclusion: Generally, the analysis of the chemical composition of essential oils proved that laboratory essential oil and commercial essential oils were extracted from different parts of plant and commercial essential oils showed stronger antioxidant activities than laboratory essential oil. This evidence could be due to low levels of phenolic and monoterpene components in laboratory cinnamon essential oil.