Chemical composition and antioxidant activities of the essential oil of Hypericum gaitii Haines – an endemic species of Eastern India

The present study reports the chemical composition and antioxidant activities of the essential oil extracted from the leaves and tender branches of Hypericum gaitii Haines (Hypericaceae) – an endemic plant of Eastern India. On hydrodistillation, the fresh leaves and tender parts of H. gaitii yielded 0.43% (v/w) of pale yellowish essential oil. Gas chromatography mass spectrometry analysis revealed the presence of 40 compounds, which represent 96.9% of the total oil. Monoterpene hydrocarbons (79.3%) predominated followed by sesquiterpene hydrocarbons (12.6%). Of these, α-pinene (69.5%), β-caryophyllene (10.5%), sabinene (5.6%), myrcene (3.0%) and geranyl acetate (2.0%) were the main constituents. Antioxidant activities of oil were evaluated by three different systems namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and reducing power assay. Essential oil exhibited moderate antioxidant activities compared to butylated hydroxytoluene (BHT) and ascorbic acid.