Cyclodextrin-based Gas Chromatography and GC/MS methods for determination of chiral pair constituents in mint essential oils

ABSTRACT

The genus Mentha has been known as culinary source of minty note. Besides, the essential oil imparts value to consumer products like confectionery, cosmetics, and pharmaceutical preparations. A simple and sensitive enantioselective gas chromatographic method is described for the quantitative analysis of terpenoid enantiomers in essential oils using different cyclodextrin coated stationary phases.  Limonene, menthone, menthol, and menthyl acetate were identified as pure (-)-enantiomers whereas isomenthone, neomenthol, pulegone, and piperitone as pure (+)-enantiomers in menthol mint, and peppermint oils, respectively. The selectivity of each enantiomer was also demonstrated. A β-cyclodextrin phase with diethyl substitution provides baseline resolution for all target enantiomers with selectivity ranged from 1.004 to 1.050. Moreover, permethylated or diacetylated-β-cyclodextrin showed no selectivity for (+/-)-menthol enantiomers. The current study may facilitate the origin authentication studies of mint oils. Investigation of enantiomers involved in menthol biosynthesis revealed that only (-)-menthol is present in the essential oils of Mentha species.

KEYWORDS:

• Essential oil
• cyclodextrin
• gas chromatography
• GC-MS
• chiral pair
• Mentha arvensis
• M. piperita

Acknowledgments

Authors are thankful to the Director, CSIR-CIMAP, for encouragement and support. We are thankful to Dr Saudan Singh, Chief Scientist, Agronomy and Soil Science and other experimental farm staffs, who helped in providing authentic plant materials. This work was jointly supported by SERB, Department of Science and Technology, New Delhi, India under Fast Track grant (SR/FT/CS-036/2010) and CSIR, New Delhi project entitled, “Chemical Biology of Ocimum and other aromatic plants (BSC 203)”.

Dedication

This paper is dedicated to Dr Chandra S Mathela, formerly, Professor and Head, Chemistry Department, Kumaun University, Nainital, Uttarakhand, India on the Occasion of His 70th Birthday.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary Material

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by the DST, New Delhi India [SR/FT/CS-036/2010]; CSIR [BSC 203].