Supercritical CO2 Extracts and Volatile Oil of Basil (Ocimum basilicum L.) Comparison with Conventional Methods
Chemical Engineering and Biotechnology Research Center, Instituto Superior de Engenharia de Lisboa, IPL, 1959-007 Lisboa, Portugal
Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
CITAB-Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal
CBiOS, Research Center for Biosciences & Health Technologies, ULHT, 1749-024 Lisboa, Portugal
iMED, ULisboa, Research Institute for Medicines, Faculty of Pharmacy, ULisboa, 1749-003 Lisboa, Portugal
IBEB, Biophysics and Biomedical Engineering, Faculty of Sciences, ULisboa, Campo Grande, 1749-016 Lisboa, Portugal
Author to whom correspondence should be addressed.
Separations 2018, 5(2), 21; https://doi.org/10.3390/separations5020021
Received: 23 January 2018 / Revised: 6 March 2018 / Accepted: 19 March 2018 / Published: 27 March 2018
(This article belongs to the Special Issue Supercritical Fluid Extraction)
Interest in new products from aromatic plants as medical and nutritional compounds is increasing. The aim of this work was to apply different extraction methods, including the use of supercritical carbon dioxide extraction, and to test the antioxidant activity of basil (Ocimum basilicum L.) extracts. In vitro efficacy assessments were performed using enzymatic assays. Essential oil obtained by hydrodistillation and volatile oil obtained from supercritical fluid extraction were analyzed by gas chromatography to quantify components. The total phenolic content in the extracts ranged from 35.5 ± 2.9 to 85.3 ± 8.6 mg of gallic acid equivalents and the total flavonoid content ranged from 35.5 ± 2.9 to 93.3 ± 3.9 micromole catechin equivalents per gram of dry weight of extract. All the extracts showed an antioxidant activity with 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS), and the reducing power test. Extracts obtained from methanol had a higher antioxidant capacity per the DPPH test results (IC50 = 3.05 ± 0.36 mg/mL) and the reducing power test assay 306.8 ± 21.8 μmol of trolox equivalents per gram of extract (TE/g) compared with ethanolic or supercritical fluid extracts. However, using the ABTS assay, the extract obtained by supercritical fluid extraction had a higher antioxidant capacity with an IC50 of 1.74 ± 0.05 mg/mL. Finally, the examined extracts showed practically no acetylcholinesterase (AChE) inhibitory capacity and a slight inhibitory activity against tyrosinase.