Volatiles Profiling in Medicinal Licorice Roots Using Steam Distillation and Solid-Phase Microextraction (SPME) Coupled to Chemometrics

Authors

  • Mohamed A. Farag,

    1. Author Farag is with Leibniz Inst. of Plant Biochemistry, Dept. Bioorganic Chemistry, Weinberg 3, D-06120 Halle (Saale), Germany; and with Pharmacognosy Dept., College of Pharmacy, Cairo Univ., Cairo, Kasr el Aini st., 11562, Egypt. Author Wessjohann is with Leibniz Inst. of Plant Biochemistry, Dept. Bioorganic Chemistry, Weinberg 3, D-06120 Halle (Saale), Germany. Direct inquiries to Author Farag (E-mail: mfarag73@yahoo.com).
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  • Ludger A. Wessjohann

    1. Author Farag is with Leibniz Inst. of Plant Biochemistry, Dept. Bioorganic Chemistry, Weinberg 3, D-06120 Halle (Saale), Germany; and with Pharmacognosy Dept., College of Pharmacy, Cairo Univ., Cairo, Kasr el Aini st., 11562, Egypt. Author Wessjohann is with Leibniz Inst. of Plant Biochemistry, Dept. Bioorganic Chemistry, Weinberg 3, D-06120 Halle (Saale), Germany. Direct inquiries to Author Farag (E-mail: mfarag73@yahoo.com).
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  • Disclosure Statement: The authors declare no actual or potential conflict of interest including any financial, personal, or other relationships with other people or organizations.

Abstract

Abstract:  Licorice (Glycyrrhiza glabra L.) is a plant of considerable commercial importance in traditional medicine and for the flavor and sweets industry. Although Glycyrrhiza species are very competitive targets for phytochemical studies, very little is known about the volatiles composition within that genus, although such knowledge can be suspected to be relevant for understanding the olfactory and taste properties. To provide insight into Glycyrrhiza species aroma composition and for its use in food and pharmaceutical industry, volatile constituents from G. glabra, G. inflata, and G. echinata roots were profiled using steam distillation and solid-phase microextraction. Two phenols, thymol and carvacrol, were found exclusively in essential oil and headspace samples of G. glabra, and with highest amounts for samples that originated from Egypt. In G. echinata oil, (2E, 4E)-decadienal (21%) and β-caryophyllene oxide (24%) were found as main constituents, whereas 1α, 10α-epoxyamorpha-4-ene (13%) and β-dihydroionone (8%) predominated G. inflata. Principal component and hierarchical cluster analyses clearly separated G. echinata and G. inflata from G. glabra; with phenolics and aliphatic aldehydes contributing mostly for species segregation.

Practical Application:  Licorice (Glycyrrhiza glabra) has large economic, nutritional, and medicinal values. The data presented in this article help in licorice quality control analysis to identify G. glabra from its closely allied species. The presence of thymol and carvacrol exclusively in G. glabra suggests that these volatiles could serve as chemotaxonomic markers and also might be considered as potentially relevant for taste.

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