Chemical composition, antioxidant and antimicrobial activity of the turmeric essential oil (Curcuma longa L.)

Abstract

In the present work, essential oil has been obtained by Clevenger-type hy-drodestillation from grounded curcuma rhizome (Rhizoma Curcumae) (Turkey) with hydromodulus 1:5 m/V during 180 minutes. The qualitative and quantitative composition of the oil was determined by GC-MS and GC-FID spectrom-etry. The antioxidant activity of the obtained oil was determined using DPPH assay just after adding DPPH radical and after 20 min, 30 min and 45 min incubation with radical. The antimicrobial activity was determined using a disc-diffusion method. The yield of the essential oil was 0.3 cm 3 / 100 g plant material. Eight compounds were identified. The major ones were ar-turmerone (22.7%), turmerone (26%) and curlone (16.8%). The best antioxidant activity showed the oil incubated for 45 minutes with DPPH radical. EC50 values for the obtained oil were 1.784 mg/cm 3 (without incubation), 0.098 mg/cm 3 (af-ter 20 minutes), 0.072 mg/cm 3 (after 30 minutes) and 0.045 mg/cm 3 (after 45 minutes incubation with radical). The oil showed the best antimicrobial activity against Candida albicans. The results indicate that turmeric essential oil is an extremely strong antioxidant and antimicrobial (antifungal) agent with potential application in the food and pharmaceutical industries as a safer alternative to the synthetic antioxidants and antimicrobial agents.