Variation in essential oil composition of Ocimum americanum L. from north-western Himalayan region

Abstract

The essential oils of ten wild growing Ocimum americanum L. of the family Lamiaceae collected from different locations in Uttarakhand, India, were analyzed by capillary gas chromatography (GC) and GC/mass spectrometry (GC/MS). On the basis of chemical composition and cluster analysis, O. americanum was classified into six groups. Group I was significantly rich in methyl chavicol, 1,8-cineole, (E)-γ-bisabolene, β-bisabolene and eugenol, while group II has (E)-γ-bisabolene, aliphatic hydrocarbons, eugenol, β-bisabolene and methyl chavicol as major constituents. Eugenol and (E)-caryophyllene were found in abundant quantity in group III and linalool with methyl chavicol in group IV. Group V contained aliphatic hydrocarbons, eugenol, camphor and 1,8-cineole in high content while camphor and aliphatic hydrocarbons were found in group VI. Linalool was positively correlated with methyl chavicol, while eugenol with (E)-α-bisabolene and β-bisabolene with (E)-γ-bisabolene. The essential oil composition of O. amercanum was found to be affected by variation in soil properties and microclimatic conditions.

Keywords:

• Ocimum americanum L
• groups
• eugenol
• methyl chavicol
• camphor
• linalool
• δ-cadinene
• bisabolenes

Acknowledgements

The author is grateful to the Director, USERC, Dehradun, for financial support and the Head, Chemistry Department, Kumaun University, Nainital, for providing the necessary laboratory facilities and encouragement.