Programa de Pós-Graduação em Engenharia de Recursos Naturais da Amazônia, Universidade Federal do Pará, Belém 66075-110, Pará, Brazil.
Coordenação de Botânica, Museu Paraense Emílio Goeldi, Belém 66077-830, Pará, Brazil.
Molecules. 2021 Apr 30;26(9):2621. doi: 10.3390/molecules26092621.
Leaves of (Verbenaceae) were dried in an oven at 40, 50 and 60 °C and the kinetic of drying and the influence of the drying process on the chemical composition, yield, and DPPH radical scavenging activity of the obtained essential oils were evaluated. The composition of the essential oils was determined with gas chromatography-mass spectrometry and gas chromatography-flame ionization detection analyses. The influence of drying on the chemical composition of the essential oils of was evaluated by multivariate analysis, and their antioxidant activity was investigated via the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The Midilli model was the most appropriate to describe the behavior of drying kinetic data of leaves. Thymol was the major compound for all analyzed conditions; the maximum content was obtained from fresh leaves (62.78 ± 0.63%). The essential oils showed DPPH radical scavenging activity with an average of 73.10 ± 12.08%, and the fresh leaves showed higher inhibition (89.97 ± 0.31%). This is the first study to evaluate the influence of drying on the chemical composition and antioxidant activity of essential oils rich in thymol.
（马鞭草科）的叶子在 40、50 和 60°C 的烘箱中干燥，并评估了干燥动力学以及干燥过程对获得的精油的化学成分、产率和 DPPH 自由基清除活性的影响。用气相色谱-质谱和气相色谱-火焰离子化检测分析确定精油的组成。通过多元分析评估了干燥对 精油化学成分的影响，并通过 2,2-二苯基-1-苦基肼（DPPH）测定法研究了它们的抗氧化活性。米利迪模型最适合描述 叶子干燥动力学数据的行为。在所有分析条件下，百里香酚都是主要化合物；从新鲜叶子中获得的含量最高（62.78±0.63%）。精油具有 DPPH 自由基清除活性，平均为 73.10±12.08%，新鲜叶子的抑制作用更高（89.97±0.31%）。这是首次评估干燥对富含百里香酚的 精油化学成分和抗氧化活性的影响的研究。
