Industrial Crops and Products 62 (2014) 22–33 Contents lists available at ScienceDirect Industrial Crops and Products jo u r n al homep age: www.elsevier.com/locate/indcrop Comparative chemotype determination of Lamiaceae plants by means of GC–MS, FT-IR, and dispersive-Raman spectroscopic techniques and GC-FID quantification Raquel Rodríguez-Solana a,b,c , Dimitra J. Daferera c , Christina Mitsi c , Panayiotis Trigas d , Moschos Polissiou c , Petros A. Tarantilis c,∗ a Department of Chemical Engineering, Sciences Faculty, University of Vigo (Campus Ourense), As Lagoas s/n, 32004 Ourense, Spain b Laboratory of Agro-food Biotechnology, CITI-Tecnópole, Parque Tecnológico de Galicia, San Cibrao das Vi˜ nas, Ourense, Spain c Laboratory of Chemistry, Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos, 118 55 Athens, Greece d Laboratory of Systematic Botany, Department of Crop Science, Agricultural University of Athens, 75 Iera Odos, 118 55 Athens, Greece a r t i c l e i n f o Article history: Received 24 April 2014 Received in revised form 29 July 2014 Accepted 6 August 2014 Keywords: Hydrodistillation Simultaneous steam distillation – solvent extraction (SDE) Gas chromatography–mass spectrometry Gas chromatography-flame ionization detector FT-IR Dispersive-Raman Chemotype Lamiaceae a b s t r a c t Three different techniques: the classical gas chromatography–mass spectrometry (GC–MS) and two “green” alternative techniques to the classical chromatography, the spectroscopic techniques Fourier transform infrared (FT-IR), and dispersive-Raman were employed to characterize the main chemotypes of different essential oils from plants of the Lamiaceae family and to compare between techniques. Gas chromatography-flame ionization detector (GC-FID) was also employed to quantify the main compounds present in essential oils isolated by hydrodistillation (HD) and semi-quantify essential oil composition isolated by HD and simultaneous steam distillation – solvent extraction (SDE). While GC cannot dif- ferentiate between pure and mixed chemotypes of a compound, FT-IR, and Raman methods allow the creation of libraries, through which chemotype determination is feasible even for mixed chemotypes, thus combining robustness with being rapid and non-destructive techniques. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Individual plants species of the same genus present distinct chemical profiles called chemotypes. Chemotypes are defined as organisms categorized under the same species, subspecies or varieties having differences in quantity and quality of their compo- nent(s) in their whole chemical fingerprint that is related to genome or gene expression differences. These chemotypes can be classified into two types: “pure chemotypes” (only one oil component, the major one, defines “the pure chemical race” and accounts for over 50% of the total essential oil) and “mixed chemotypes” (where there are 2–3 main components, each accounting for less than 50% of the essential oil, which, as an entity, define the chemical composition) (Holopainen et al., 1987; Polatoglu, 2013). ∗ Corresponding author. Tel.: +302105294262; fax: +302105294265. E-mail address: ptara@aua.gr (P.A. Tarantilis). The knowledge of the chemotype of an essential oil is impor- tant as numerous species of the Lamiaceae family present chemical polymorphism, i.e. individual plants have various genotypes which code the production of different dominant terpenes in their essen- tial oil (Keefover-Ring et al., 2009). The determination of chemotype is essential in order to understand the regulatory pathways of sec- ondary metabolism (Yamazaki and Saito, 2011). Furthermore, each chemotype, as determined by genotype, environment, agronomic treatments and their interactions, presents distinct biological activ- ity of its essential oil (Rota et al., 2008). Essential oils can be isolated from plant tissues using various techniques. Hydrodistillation (HD) and simultaneous steam distil- lation – solvent extraction (SDE) using Likens-Nickerson apparatus are two classical techniques, well known to yield a rich profile of the essential oil (Daferera et al., 2002a, 2002b; Viljoen et al., 2006). However, these techniques present some disadvantages, the main being thermal transformation of molecules and loss of hydrophilic compounds (Prosen et al., 2010). http://dx.doi.org/10.1016/j.indcrop.2014.08.003 0926-6690/© 2014 Elsevier B.V. All rights reserved.