Enantiomeric Composition of (3R)-(-)- and (3S)-(+)-Linalool in Various Essential Oils of Indian Origin by Enantioselective Capillary Gas Chromatography-Flame Ionization and Mass Spectrometry Detection Methods

Abstract

Enantiomeric ratios of linalool have been determined in various authentic essential oils of Indian origin using 10% heptakis(2,3-di- O-methyl-6- O-tert-butyldimethylsilyl)-β-cyclodextrin as a chiral stationary phase. A complete enantiomeric excess (ee) for (3 S)-(+)-linalool was characteristic of Lippia alba and Cinnamomum tamala leaf oils while less than 90% excess was noticed in Zanthoxylum armatum leaf, Zingiber roseum root/rhizome and Citrus sinensis leaf oils. On the contrary, an enantiomeric excess of (3 R)-(-)-linalool characterizes essential oils of basil (100% for Ocimum basilicum) and bergamot mint (72 to 75% for Mentha citrata). Notably, some essential oils containing both enantiomers in equal ratios or in racemic forms are rose, geranium, lemongrass and Origanum. The enantiomeric composition studies are discussed as indicators of origin authenticity and quality of essential oil of Indian origin.