Antioxidant activity of hydroalcoolic extracts of green and ripe scarlet eggplants (SOLANUM AETHIOPICUM GR. GILO)

The scarlet eggplant or ‘jiló’ fruit (Solanum aethiopicum gr. Gilo) has a characteristic pleasant bitter taste, low energy value and high content of dietary fibers. The fruits are frequently eaten green and when ripe, they are considered unsuitable for consumption and commercialization. Phytochemical studies of scarlet eggplant are rare and little is known about the polyphenols present in this fruit. The extraction procedure with an ethanol-water solution (70:30) of our samples allowed extract yields of 29% and 35% for the green and ripe fruit, respectively. The total phenolic content (TPC) of immature and ripe hydroethanolic fruit extracts were 4.46 ± 0.33 and 6.52 ± 0.01 µg GAE/mg of extract, respectively. Likewise, the antioxidant capacities evaluated by the FRAP, hydroxyl and DPPH assays were higher for the ripe fruit extract, which is likely related to the superior TPC value presented by this sample. The data set obtained in this work confirms that the green fruit of scarlet eggplant is rich in antioxidant polyphenols. Although ripe ‘jiló’ fruits present hardened seeds and are considered out of commercial standard, our results indicate, at least in principle, that these by-products are potential sources of polyphenols to antioxidant supplements manufacture.