Influence of extraction solvents on the polyphenol contents, compositions, and antioxidant capacities of fig (Ficus carica L.) seeds

Fig seeds are considered to be significantly responsible for the bioactive compounds of fig. In this study, the effects of six different solvents (100% acetone, 100% methanol, 100% ethanol, 50% (v/v) aqueous acetone, 50% (v/v) aqueous methanol and 50% (v/v) aqueous ethanol) with changing polarities on the polyphenol contents and antioxidant capacities of fig seed extracts were investigated. Total polyphenol contents (TPCs), total flavonoid contents (TFCs), antioxidant capacities (DPPH and FRAP assays) and polyphenol compositions of the extracts were evaluated. The results indicated that fig seeds extracted by 50% (v/v) aqueous methanol exhibited the highest TPC (714 mg GAE/ kg DM), TFC (312 mg (+)-CE/ kg DM), DPPH (41.6%) and FRAP (8504 mg FeSO4/ kg DM) values. Also, same extract had the maximum values of chlorogenic acid (131.9 mg/kg DM), (-)-epicatechin (166.4 mg/kg DM) and rutin (50.7 mg/ kg DM) (p<0.05). The extractability of syringic acid was determined to be highest with 50% aqueous methanol (8.03 mg/kg DM) and 50% aqueous ethanol (8.13 mg/kg DM) (p>0.05). The psoralen extractability was highest in 50% aqueous acetone (53.0 mg/kg DM) and 50% aqueous ethanol (54.0 mg/kg DM) (p>0.05). High correlations among TPCs, TFCs, antioxidant capacities and individual polyphenols of fig seed extracts were also observed.