Shades of red: comparative study on supercritical CO2 extraction of lycopene-rich oleoresins from gac, tomato and watermelon fruits and effect of the ?-cyclodextrin clathrated extracts on cultured lung adenocarcinoma cells' viability

Lycopene is a red carotenoid thought effective in preventing
some types of cancers and modulating immune and inflammatory responses.
Though some fruits share the common feature of synthesizing and storing
lycopene as main carotenoid within chromoplasts, they significantly
differ in the lipophilic phytocomplex. The purpose of this work was: i)
to extract solvent-free lycopene-rich oleoresins from gac, tomato and
watermelon ripe-fruits by supercritical CO2 suitable for functional food
and nutraceutical formulations; ii) characterize the oleoresins with
respect to carotenoids, tocochromanols, lipids, metals and antioxidant
activity; iii) prepare stable aqueous suspensions through oleoresin
clathration into ?-cyclodextrins (?-CDs); iv) investigate the effect of
each lycopene-containing suspension on viability of human lung
adenocarcinoma cells.
The results showed that all oleoresins represent a safe added-value
source of lycopene characterized by high lipophilic antioxidant activity,
improved by the synergy with other biomolecules. Interestingly, when
administered at identical concentrations (0.5-10 ?M) of lycopene, the
extracts showed conflicting behaviors: gac and tomato suspensions
significantly increased cell viability, whereas watermelon oleoresin/?-CD
suspension significantly decreased cell viability. Although further
studies are required, this research suggests a fundamental role of
phytocomplex in affecting the responses of cancer cell survival to the in
vitro administration of lycopene.