Composition and antioxidant activity, supercritical carbon dioxide extraction extracts, and residue after extraction of biologically active compounds from freeze‐dried tomato matrix

Abstract

Supercritical carbon dioxide extraction (SCE‐CO2) is an attractive, green technology that is used for the recovery of biologically active compounds from plant material. The antioxidant potential of lipophilic fractions (extract obtained with SCE‐CO2) and hydrophilic fractions (extracts obtained from the residue after extraction) obtained from a matrix of freeze‐dried tomatoes (cvs. “Admiro” F1, “Jurgiai”, “Vilina”, “Pirmutis”, and “Skariai”) was assessed via different antioxidant activity methods. The total amount of polyphenols, carotenoids, and carotenoid isomers before and after SCE‐CO2 extraction was also determined. To investigate the effect of the SCE‐CO2 extract on the viability of cancer cells, rat glioblastoma C6 cells were chosen. The SCE‐CO2 yielded an average of 800 mg of lipophilic fraction per 100 g of freeze‐dried tomatoes. The ABTS•+ scavenging activity of the extract was 251 ± 3.4 μmol TE/g. After SCE‐CO2 extraction, the DPPH• ‐RSA of the freeze-dried tomato matrix was 7 to 12% higher. There was a strong positive correlation (R = 0.84) between the total polyphenolics content and the DPPH•‐RSA of the tomato samples. The SCE‐CO2 increased the radical scavenging activity of the extraction residue, indicating that a considerable fraction of the hydrophilic compounds with particular antioxidant capacity remain unextracted from the tomato matrix. Our results reveal the cytotoxic effect of lycopene extract rich in cis‐isomers (62% cis-isomers of the total lycopene content) on rat glioblastoma C6 cells. The viability of the glioblastoma C6 cells significantly decreased (−42%) at a total lycopene concentration of 2.4 μM after 24 h of in-cubation.