Health turns red: comparative study on supercritical CO2 extraction of lycopene from fruits and effect of the nanocarrier encapsulated oleoresins on cultured lung adenocarcinoma cells.

Lycopene is a carotenoid pigment found in a wide variety of vegetables and fruits. More than six hundred carotenoids have been identified in nature, but only twenty are present in human blood and tissues, including lycopene (the most abundant in plasma), ?-carotene, lutein and zeaxanthin [1]. Several exogenous pigmented antioxidants act on cancer progression and have immune-modulating effects by free radical scavenging activity and/or still unknown mechanisms. However, the controversy recently arisen for some of them requires a careful investigation in relation to their source and synergistic effects [2]. The purpose of this work was: i) to optimize the extraction of lycopene from ripe fruits of tomato, watermelon and GAC by supercritical CO2 in order to obtain natural, solvent-free lycopene containing oleoresins suitable as ingredients for the formulation of innovative functional foods and/or nutraceuticals; ii) to characterize each oleoresin with respect to carotenoids, tocochromanols, lipids, lipophilic and hydrophilic antioxidant activities, micro and macro elements; iii) the preparation of inclusion complexes (ICs) of the oleoresins in food grade ?-cyclodextrins (?-CDs) as hydrophilic nanocarriers [3]; iv) to assess, in-vitro, the effects of administration of each oleoresin/?-CD IC at different concentrations (0.5 to 10 µM) on cell apoptosis and on Interleukin-8 (IL-8) release by A549 human lung adenocarcinoma cells, for 24, 48 and 72 hours. The results showed that all oleoresins represent a healthy and high added-value source of lycopene characterized by: i) the absence of toxic impurities such as solvents, pesticides and heavy metals; ii) a high lycopene bioavailability, increased by the presence of co-extracted natural lipophilic components; iii) a high lipophilic antioxidant activity, improved by synergy with other biomolecules. When administered at a concentration of 10 µM for 72 hours, the three lycopene extracts showed conflicting behaviors: watermelon oleoresin increased cell apoptosis and decreased the release of IL-8, a pro-inflammatory cytokine involved in cancer progression; GAC and tomato oleoresins, instead, decreased cell apoptosis and increased IL-8 release. This discrepancy is likely related to a different lycopene/vitamin E ratio, with watermelon oleoresin showing the highest value among the extracts. Shorter incubation time and lower lycopene concentrations did not affect cell viability and IL-8 release. Further studies are required to assess the possible use of the lycopene containing oleoresin/?-CD ICs in health promoting functional foods and nutraceuticals.