Physicochemical and nutritional profile of leaves, flowers, and fruits of the edible halophyte chorão-da-praia (Carpobrotus edulis) on Portuguese west shores

Abstract

Leaves, flowers and fruits from the edible halophyte chorão-da-praia (Carpobrotus edulis), harvested in the Portuguese western sea shores, were characterized regarding their proximate composition, fatty acid profile, pigments, phenolic compounds, antioxidant and antimicrobial activities. Fruits had the highest amount of carbohydrates (70.2 ± 1.6%) and the lowest of protein (4.67 ± 0.22%) and ash (22.0 ± 1.0%) contents. No significant differences were observed in the lipid fraction. Leaves were mainly constituted by saturated (52.6 ± 1.3%) fatty acids (FA), whereas fruits showed the highest amount of polyunsaturated FA (48.6 ± 3.1%). Chlorophylls and carotenoids were more abundant in leaves. Aqueous-ethanolic (1:1, v/v) extract of flowers exhibited the highest phenolic content (299 ± 8 μg/mg of gallic acid equivalents), by the Folin–Ciocalteu methodology, as well as the strongest antioxidant activity (IC50 = 11.83 ± 1.0 μg/mL and 7.82 ± 0.24 μmol/mg of ascorbic acid equivalents by the DPPH and FRAP methods, respectively). Also, flowers extract showed the most pronounced antimicrobial activity by the microtiter broth dilution method. Mass and tandem mass spectra revealed that the most abundant species in all extracts were glycosylated and/or acetylated O-Methyl flavonols, mainly derived from syringetin and laricitrin. Nuclear magnetic resonance was also employed for complementary confirmation of the syringetin moieties. Regarding the profile in polyphenols, when comparing leaves, flowers and fruits, one concluded that there were clearly differences in the relative amount of these polyphenols, being flowers richer in the syringetin derivatives. In conclusion, this edible plant, classified as an invasive species of the Portuguese coast, highlights for its richness in bioactive compounds with potential application in the food industry.