Determination of phenolic composition and antioxidant activities of Pancratium maritimum L. from Tunisia

Abstract

During these last few years, the Pancratium species are the focus of an increasing number of researches due to their interesting biological properties. For the purpose of this research, the phenolic composition of Tunisian Pancratium maritimum was analysed by HPLC-DAD-ESI–MSn. Samples, including leaves and bulbous parts, divided separately into scales and tunics, were collected from two different localities.The samples analysis revealed the presence of nineteen compounds, including five phenolic acids and fourteen flavonol glycosides. Quercetin and isorhamnetin glycosides were the main flavonols present in the species. Quercetin tri-hexoside, quercetin hexoside I, isorhamnetin di-hexoside II and isorhamnetin hexoside II were detected in the foliar extracts only. Two other isorhamnetin derivatives (isorhamnetin pentoside-hexoside and isorhamnetin glucuronide) were exclusively identified in the bulb tunic extracts. The antioxidant capacities using oxygen radical absorbance capacity (ORAC), 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and metal chelating activity (MCA) assays were evaluated. Significant differences were observed among plant parts. Leaves (LP1) exhibited significantly (p<0.05) the strongest ORAC and DPPH inhibition (182 and 372mg/g, respectively), compared with the bulbous parts. While, the highest capacity for chelating metal ions was reported for both bulb tunics TP2 and TP1 (23 and 31mg/g, respectively).In conclusion, P. maritimum, a well known source of Amaryllidaceae alkaloids, can provide a good source of antioxidant compounds particularly leaves as potent radical scavengers.