Evaluation of the antioxidant capacity of Psoralea glandulosa L. (Fabaceae) extracts

The antioxidant properties of different extracts of culen (Psoralea glandulosa L., Fabaceae) herb from Gran Valparaíso location in Chile were evaluated. Antioxidant capacity was assessed in four different model systems. Antioxidant models were examined by measuring the scavenging activity of extracts on 2,2-diphenyl-1-pycrylhydrazil (DPPH·) as well as on hydrogen peroxide (H2O2), the oxidant species. In addition, extracts were evaluated by ferric reducing antioxidant power (FRAP) and the total peroxyl radical-trapping potential (TRAP). The amount of dried extract, the content of total phenolics, flavonoids and hydrolyzed sugar were also determined. The leaves extracts from culen expressed very strong scavenging activity, reducing the DPPH· (IC50 = 1.00 mg/mL to 1.61 mg/mL) and neutralizing H2O2 (IC50 = 34.29 mg/mL to 64.87 mg/mL). Also, dichloromethane extract of the leaves showed notable index of FRAP (2.71 mM) and TRAP (1.19 mM). The results suggest strong antioxidant potential of dichloromethane and ethyl acetate extracts of leaves of P. glandulosa that could be partially explained by the levels of phenolics (1.65 mg GAE/g dry extract) and flavonoids (55.34 mg QE/g dry extract) respectively.