Title: | Chemometric analysis of NMR and GC datasets for chemotype characterization of essential oils from different species of Ocimum |
Author(s): | Freitas JVB; Alves Filho EG; Silva LMA; Zocolo GJ; de Brito ES; Gramosa NV; |
Address: | "Departamento de Quimica Organica e Inorganica, Universidade Federal do Ceara, Fortaleza, CE, Brazil. Embrapa Agroindustria Tropical, Fortaleza, CE, Brazil. Departamento de Quimica Organica e Inorganica, Universidade Federal do Ceara, Fortaleza, CE, Brazil. Electronic address: nilce@dqoi.ufc.br" |
DOI: | 10.1016/j.talanta.2017.12.053 |
ISSN/ISBN: | 1873-3573 (Electronic) 0039-9140 (Linking) |
Abstract: | "The genus Ocimum (Labiatae) comprises 30 species found in tropical and subtropical regions of the planet, of which species O. basilicum L. and O. gratissimum are widely used in food and traditional medicine. Phytochemical studies on Ocimum have revealed a number of essential oil chemotypes, for example, eugenol, methyl chavicol, linalool, and methyl cinnamate. Since essential oils are commercially assessed according to their content, the aim of this study was to develop a simple and precise method for their qualitative and quantitative analysis using NMR spectroscopy combined with chemometrics. Seven essential oils from different species of Ocimum, an unknown sample, and a commercial sample were evaluated and the results compared to those from established and precise GC-MS and GC-FID methods. Chemometric evaluation from both (1)H NMR and GC-MS data revealed three chemotypes: eugenol for O. gratissimum, O. micranthum, and O. tenuiflorum; estragole for O. basilicum, O. basilicum var. purpuracens, and O. selloi; and methyl cinnamate for O. americanum. The unknown and commercial species were classified as cinnamate and eugenol chemotypes, respectively. Despite the corroborating results, the chemometric analysis revealed the higher robustness (better adjustment) of the (1)H NMR model compared to the GC-MS method in terms of certain statistical parameters. The (1)H NMR method allows for the detection and quantification of organic compounds in a complex mixture without the need for certified standard compounds. Although GC-MS and GC-FID were able to detect five compounds not observed by NMR spectroscopy, the four most important metabolites (eugenol, estragole, methyl cinnamate, and eucalyptol) were more readily detected and quantified by (1)H NMR" |
Keywords: | "Acyclic Monoterpenes Allylbenzene Derivatives Anisoles/analysis Chromatography, Gas/*methods Cinnamates/analysis Cyclohexanols/analysis Eucalyptol Eugenol/analysis Gas Chromatography-Mass Spectrometry/methods Magnetic Resonance Spectroscopy/*methods Monot;" |
Notes: | "MedlineFreitas, Joao Vito B Alves Filho, Elenilson G Silva, Lorena Mara A Zocolo, Guilherme J de Brito, Edy S Gramosa, Nilce V eng Netherlands 2018/01/16 Talanta. 2018 Apr 1; 180:329-336. doi: 10.1016/j.talanta.2017.12.053. Epub 2017 Dec 21" |