Figure 4.

Principal component analysis (PCA) of the groups of metabolites and antioxidant capacity of Robinia pseudoacacia leaf and flower extracts in two solvents (70% EtOH and 80% MeOH). (A) Score plot separating the flower and leaf extracts based on the measured groups of metabolites and antioxidant capacity; (B) loading plot of the measured variables; TP = total phenolics, TF = total flavonoids, TNF = total nonflavonoids, ABTS = 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt assay, FRAP = ferric reducing antioxidant power assay, DPPH = 2,2-diphenyl-1-picrylhydrazyl assay, HBA = Hydroxybenzoic acids, HCA = Hydroxycinnamic acids. The differences between different populations are not reported in this contribution.