Nutraceutical potential of polyphenolic fractions from Annurca apple (M. pumila Miller cv Annurca)

The capacities of polyphenolic extracts from Annurca apple peel and flesh to inhibit the glucose and cholesterol uptake by HepG2 cells were evaluated, and compared with those of other conventional cultivars, such as Red Delicious (RD), Pink Lady (PL), Fuji (F) and Golden Delicious (GD). RD peels exhibited the best hypoglycaemic effects, while Annurca flesh appeared the most active in reducing cell cholesterol uptake among the cultivars tested. The influence of the apple polyphenolic extracts on the cell proliferation and oxidative stress was also evaluated. Particularly, RD, Annurca and PL peels decreased proliferation by a 62.5%, 48.0% and 37.5%, respectively, probably due to their prooxidant capacity. Conversely, flesh extracts appeared more protective of cells than peels: Annurca and RD, particularly, proved to be able of increasing proliferation by a 32.2% and 11.1%, respectively, probably due to their capacity of reducing cell physiological radical levels of a 33.3% and 19.9%, respectively.

► Polyphenolic extracts from five apple cultivars were tested on HepG2 cells.
► Red Delicious (RD) peels were the most effective in reducing glucose uptake.
► RD peels and Annurca flesh showed the best activity in decreasing cholesterol uptake.
► On average, apple peel extracts revealed cytotoxicity by inducing oxidative stress.
► Annurca flesh showed the best radical-scavenging properties and allowed proliferation.