Chemical composition and antioxidant activity of the essential oil and various extracts of Haplophyllum robustum Bge.

This study was designed to examine the chemical composition and in vitro antioxidant activity of the essential oil and various extracts of Haplophyllum robustum. GC-MS analysis of the oil resulted in the identification of 30 compounds, representing 99.2% of the oil; 1,8-cineole (38.1%), myrcene (10.7%), α-pinene (8.5%), 4-terpineol (7.0%) and sabinene (6.1%) were the main components. The antioxidant potential of the oil and extracts was evaluated using three separate methods: inhibition of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), ß-carotene-linoleic acid assay and reducing power systems. The essential oil of the plant was able to reduce the stable free radical DPPH with an IC(50) of 72.0 ± 1.2 µg mL(-1) (the IC(50) for ascorbic acid was determined as 5.8 ± 0.4 µg mL(-1)). The essential oil also showed strong reducing power. The level of total phenolics was highest in the essential oil (179.5 ± 2.1 µg mg(-1)).