Essential oil and smoke components of Indigofera Arrecta

Abstract

Indigofera arrecta, commonly known as Buk-Buk (Amharic) in Ethiopia, is an important traditional medicinal plant among Ethiopians which is used for the treatment of different ailments.  In this study, major components of the essential oil and the smoke obtained from burned I. arrecta were investigated. The smoke from burnt plant material was trapped in methanol and hexane solvents. Using GC-MS, about seventeen compounds were identified from the essential oil, which accounted for 95.10%. Octylacetate (28.54%) was the major component of the essential oil. On the other hand, the solid (sublimed) material obtained during hydrodistillation showed six compounds with a total percent area of 94.88%. The sublimed material was dominated by 1,2,4,5-tetrachloro-3,6-dimethoxybenzene, which accounted for 88.36%. The smoke of I. arrecta showed nine compounds with a combined area of 100%, of which 2, 4-di-tert-butylphenol (31.3%) and 1,2,4,5-tetrachloro-3,6-dimethoxybenzene (25.10%) compounds were the major components. The crude smoke extracts were also examined for their antioxidant activity by using 2,2-dipheneyl-1-picrylhydrizyl (DPPH). The smoke derived from I. arrecta showed 93.52 ± 0.09 DPPH inhibition activities at the concentration of 100 µg/mL which is closer in activity to the standard ascorbic acid. This shows a strong relationship between use of the plant smoke as medicinal incense and its antioxidant activity.