Variation of essential oil of Mentha haplocalyx Brig. and Mentha spicata L. from China

Essential oil properties of different geographical populations of Mentha haplocalyx and M. spicata were analyzed. The yield of essential oils varied in the range of 0.5-3.0% within forty-five populations. Based on essential oil composition. all M. haplocalyx accessions could be classified into six chemotypes, including linalool, pulegone, menthone, carvone, menthol, and piperitenone oxide. In particular, all chemotypes were observed in Sichuan Basin. M. spicata accessions were relatively stable in essential oil content and composition, and were grouped together into chemotype carvone. M. haplocalyx was polymorphic in essential oil properties which could be associated with its genetic diversity. Sichuan Basin in China could be a primary diversity region for M. haplocalyx rather than for M. spicata. The characterization of essential oil variation is of commercial importance as well as helpful in the improvement of Mentha resources for fragrance and pharmaceutical industries. (C) 2012 Elsevier B.V. All rights reserved.