Chemical composition, antioxidant activity and cytotoxicity of the essential oils of the leaves and stem of Tarchonanthus camphoratus

The aim of this study was to investigate the chemical composition, antioxidant potential and cytotoxicity of the essential oil of the fresh leaf, dry leaf and dry stem of Tarchonanathus campharatus. The antioxidant activity of the oils were examined by the 1,1-Diphenyl-2-picryl-hydrazil (DPPH), 2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS.+), nitric oxide radical scavenging and reducing power methods. The brine shrimp lethality test and the MTT cytotoxicity test were used to investigate the cytotoxicity of the oils. Sesquiterpene hydrocarbons are the major components  in the essential oil of the fresh leaves (36.46%) and of the dry leaves (59.18) whereas an aldehyde, butanal (35.77%) is the major  component in the essential oil of the dry stem. The oils did not show significant antioxidant activity as evidenced by their high LC50 values in all the antioxidant assays. The cytotoxicity results indicated that the oils had low toxicity with LC50 values ranging from 400 to 900 µg/ml and 400 to 1100 µg/ml for the brine shrimp lethality test and MTT cytotoxicity assay respectively.   Key words: Tarchonanthus camphoratus, essential oil, antioxidant activity, cytotoxicity.