Phenolic profiling and antioxidant capacity in flowers, leaves and peels of Tunisian cultivars of Punica granatum L.

Abstract

The comprehensive phenolic fingerprints of flowers, peels and leaves of two Tunisian Punica granatum L. cultivars, namely Nabli and Gabsi, were investigated. The highest phenolic content was recorded in the Nabli flowers, followed by Gabsi peels extracts (152.6 and 125.8mg gallic acid equivalent 100g-1, respectively) while flavonoids and flavonols were highest in Gabsi peels (19.2 and 26.0mg Rutin equivalent per 100g-1). Besides, the antioxidant capacity was the highest in Gabsi peels (144.4mg gallic acid equivalent 100g-1) and in Nabli flowers (161.6mg gallic acid equivalent per 100g-1. Methanol extracts of all three plant portions of both cultivars were screened by ultra-high-performance liquid chromatography coupled to quadruple time of flight mass spectrometry, and the identified phenolics were further quantified. Nabli cultivar showed higher contents of flavonoids (in flowers and leaves), while phenolic acids were abundant in Gabsi leaves. Multivariate statistics highlighted differences in phenolic profile among organs and cultivars. These results showed that the pomegranate portions investigated are a valuable source of bioactive compounds with health-promoting properties, mainly belonging to the phenolic class of flavonoids.