Phenolic compounds, antioxidant and antidiabetic activity of different cultivars of Ficus carica L. fruits

Fig fruit has been a typical component in the health-promoting Mediterranean diet for millennia. The aim of the study was to analyse the potential health-promoting constituents of 10 different cultivars of fig fruits (black, red, yellow, and green) and 2 varietal types (brevas and fig) grown under the same conditions in Spain. Polyphenols and triterpenoids in figs were identified by LC-PDA-QTof/MS and quantified by UPLC-PDA-FL; besides, the sugar profile, the antioxidant capacity (ORAC) and the in vitro hypoglycaemic potential via inhibition of α-amylase and α-glucosidase were evaluated. The phytochemical profiling of fig fruits revealed a wide range of bioactive phenolics that significantly depended on cultivar and varietal type. A total of 11 polyphenolic compounds were identified and classified as flavan-3-ols, phenolic acids, flavonols, flavons, and anthocyanins. The content of total polyphenols ranged from 715 ('Verdal' brevas) to 186 mg/100 g dry matter ('Campera'). Betulinic acid was the main triterpenoid (content ranging from 57 to 97%), followed by oleanolic acid. The ORAC assay showed that the cultivar 'Verdal' had the highest antioxidant activity. The inhibition of antidiabetic enzymes was significant in fruits of the cultivars 'Tiberio', 'Campera', 'Calabacita', and 'Cuello Dama Blanca' cultivars, making these four cultivars especially recommendable for fresh consumption, especially of the whole fruits.