Basil (Ocimum basilicum L.) is an annual spicy plant generally utilized as a flavouring agent for food. Basil leaves also have pharmaceutical properties due to the presence of polyphenols, phenolic acids, and flavonoids. In this work, carbon dioxide was employed to extract bioactive compounds from basil leaves. Extraction with supercritical CO2 (p = 30 MPa; T = 50 °C) for 2 h using 10% ethanol as a cosolvent was the most efficient method, with a yield similar to that of the control (100% ethanol) and was applied to two basil cultivars: "Italiano Classico" and "Genovese". Antioxidant activity, phenolic acid content, and volatile organic compounds were determined in the extracts obtained by this method. In both cultivars, the supercritical CO2 extracts showed antiradical activity (ABTS●+ assay), caffeic acid (1.69-1.92 mg/g), linalool (35-27%), and bergamotene (11-14%) contents significantly higher than those of the control. The polyphenol content and antiradical activity measured by the three assays were higher in the "Genovese" cultivar than in the "Italiano Classico" cultivar, while the linalool content was higher (35.08%) in the "Italiano Classico" cultivar. Supercritical CO2 not only allowed us to obtain extracts rich in bioactive compounds in an environmentally friendly way but also reduced ethanol consumption.
Keywords: antioxidant activity; caffeic acid; green technology; linalool; polyphenols; supercritical carbon dioxide; volatile organic compounds.