Polyphenolic profiling and chemometric analysis of leaves from Italian Ficus carica L. Varieties. Polyphenol compounds in common fig

Abstract

Ficus carica L. is a typical crop of Mediterranean traditional agricultural landscapes. Its fruits have special historical importance in the diet of Mediterranean peoples, while fruits, roots, and leaves possess medicinal and nutraceutical activity, and are used in traditional medicines. This study explores the difference in the phenolic profile of leaves of ten Italian varieties of Ficus carica L. Individual polyphenols were evaluated quantitatively by means of HPLC-DAD-TOF-MS (High-Performance Liquid Chromatography-Diode-Array Detection/Mass Spectrometry) techniques. Additionally, total phenol content was measured using the Folin-Ciocalteu assay and antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC). Chemometric analysis were used to determine fingerprinting phytochemical of the fig varieties. Eighteen phenolic compounds were determined in the fig leaves, and caffeoylmalic acid and rutin were found to be the major components. The activity of antioxidants assessed by DPPH and ORAC presented significant differences among the varieties ranging from 0.48 to 6.68 mg DW mL-1, and from 49.2 to 6.3 μM Trolox equivalent (TE) per gram of dry weight, respectively. Simple linear regression analysis between the total polyphenol and antioxidant activity values gave moderate correlation, suggesting that antioxidant activity is determined by relationship between the amount of polyphenols and the various phenolic constituents. Principal Component Analysis indicated that phenolic compounds could be responsible for the differences among fig leaf samples according to variety. The results confirm that the fig leaves can be a source of phenolic compounds, and that phytochemical fingerprinting combined with chemometric analysis can be used to characterize fig germplasm.