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1.
Food Chem ; 307: 125521, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31655264

RESUMO

The essential oils and antioxidant activity of four Thymus species were evaluated under five light spectra (namely, red, blue, red-blue, white, and greenhouse condition). The highest essential oil yield (4.17%) was observed under red light in T. migricus, while the lowest (1.05%) was observed in T. carmanicus under greenhouse conditions. Light quality also led to difference in essential oil constituents. The highest thymol (66%) was found in T. migricus exposed to blue light, while the least (1.69%) was observed in T. kotschyanus grown under red-blue light. The LED treatments did not induce any significant effect on carvacrol of Thymus species in comparison to the greenhouse condition. Finally, the analysis of variance indicates that the effect of light varied with the studied species. T. migricus performed the highest antioxidant capacity (IC50 = 176.8 µg/mL) under blue light. Overall, essential oil components as well as antioxidants showed significant responses to light emitting diodes wavelengths.


Assuntos
Antioxidantes/metabolismo , Luz , Timol/metabolismo , Thymus (Planta)/química , Análise de Variância , Antioxidantes/química , Cromatografia Gasosa , Análise por Conglomerados , Efeito Estufa , Óleos Voláteis/química , Análise de Componente Principal , Timol/química , Thymus (Planta)/crescimento & desenvolvimento , Thymus (Planta)/metabolismo
2.
Phytochemistry ; 169: 112126, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31644985

RESUMO

Thyme (Thymus spp.) is a valuable genus of Lamiaceae family with different pharmaceutical and food properties. Thymol has also been considered as the major essential oil compound in most of the studied Thymus species. In this research, the gene encoding γ-terpinene synthase (Ttps2) was sequenced in T. vulgaris and in eight Iranian thymes including T. carmanicus, T. daenensis, T. fedtschenkoi, T. kotschyanus, T. migricus, T. pubescens, T. serpyllum, and T. trautvetteri. Genetic relationships based on terpene synthase genes were also determined among the studied species. Rapid Amplification of cDNA Ends (RACE) PCR was done to complete the sequence of all species. The cDNA of the studied species possessed an open reading frame ranging from 1788 to 1794 bp that encode for a protein of 596-598 amino acids, presenting all the conserved motifs characteristics of monoterpene synthases. The taxonomic status of Thymus species was determined based on eight reported sections. The species were classified in three major groups. The first and second group comprised species of Micantes and Mastichina sections. The third cluster included the species belonging to Serpyllum and Pseudothymbra sections. Overall, phylogenetic analysis according to whole sequence of Ttps2 gene can help providing insights in respect to its evolutionary process. Finally, clustering based on the amount of main essential oils components (thymol and carvacrol) was compared with that based on Ttps2 gene classification in the studied Thymus species, showing that clustering is not always in accordance.

3.
Food Chem ; 220: 153-161, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-27855883

RESUMO

In this study, the essential oil (EO) composition, flavonoid and phenolic contents, and antioxidant activities of fourteen Thymus accessions belonging to ten species were evaluated. Gas chromatography-mass spectrometry (GC-MS) analysis revealed the presence of 38 compounds with the major constituents including thymol (12.4-79.74%), carvacrol (4.37-42.14%), geraniol (0.3-22.44%), and p-cymene (0.8-12.86%). Cluster analysis identified three groups of high thymol, geraniol/linalool, and high carvacrol. The highest phenolic and flavonoid contents were detected in T. daenensis-1 (70.6mg tannic acid equivalents (TAE) g-1 DW) and T. vulgaris (8.55mg quercetin equivalents (QE) g-1 DW), respectively. The antioxidant activities of the samples were determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and reducing power assay. The results demonstrated that T. daenensis-3 (IC50=273.36), T. vulgaris (IC50=289.3), and T. fedtschenkoi-3 (IC50=339.22) possessed higher antioxidant activities than the others. Finally, the Thymus species with high bioactive compounds may be recommended for further food applications.


Assuntos
Antioxidantes/análise , Flavonoides/análise , Óleos Voláteis/química , Fenóis/análise , Thymus (Planta)/química , Análise por Conglomerados , Cromatografia Gasosa-Espectrometria de Massas , Irã (Geográfico) , Modelos Lineares , Monoterpenos/análise , Extratos Vegetais/análise , Análise de Componente Principal , Taninos/análise , Terpenos/análise , Timol/análise , Thymus (Planta)/classificação
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