Abstract
The natural variability in the enantiomeric distribution of biologically active chiral terpenoids in Solidago canadensis L. essential oil from Kumaon was evaluated by enantioselective capillary GC, capillary GC, and GC-MS. Germacrene D, a sesquiterpene hydrocarbon, was noticed as the major compound, contributing 56.7%, 75.5% and 69.7% to the samples, while other constituents with variable compositions were limonene (0.2 to 12.5%), bornyl acetate (2.1 to 2.9%), δ-elemene (2.4 to 3.2), β-elemene (1.3 to 1.8%), and elemol (1.4 to 2.6%). The enantiomeric excess has been determined for germacrene D with (+)-enantiomer (>41.8% to >47%) dominating over the (-)-enantiomer in all the samples. Furthermore, there has been above 95% enantiomeric excess for (R)-(+)-limonene (>95.1% to >99%), whereas moderate to low excess for (1 R)-(+)-α-pinene (>47.9%), and (1S)-(-)-β-pinene (>30.3%) was established. Notably, only (-)-bornyl acetate was found as a single enantiomer with >99% enantiomeric excess. However, for all the identified chiral terpenoids, the enantiomeric distribution varied within only a narrow range in all the samples.