Characterisation of phenolic antioxidants in Scabiosa arenaria flowers by LC-ESI-MS/MS and NMR.

OBJECTIVE

This work describes the bioguided fractionation of the flower's ethyl acetate fraction of Scabiosa arenaria Forssk. (Dipsacaceae).

METHODS

The identification of the pure compound isolated has been studied by mono-dimensional NMR experiments. The mixture of phenolic compounds was analysed by LC-ESI-MS/MS. The antioxidant activity has been evaluated by the 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay.

RESULTS

The bioguided fractionation of the flower's ethyl acetate fraction of Scabiosa arenaria led to the isolation of a pure compound: luteolin. The mixture of three phenolic compounds was identified as: 1, 4-O-dicaffeoylquinic acid, apigenin 7-O-glucoside and luteolin-7-O-glucoside. Two of which are reported here for the first time in Scabiosa genus. Luteolin had the highest antioxidant activity with an IC50 value of 0.02 ± 0.007 mg/ml, followed by the three phenolic compounds with an IC50 value of 0.025 ± 0.008 mg/ml.

CONCLUSIONS

The results of the present work indicate that S. arenaria flower's ethyl acetate extract could be used as natural antioxidant agents in food preservation and human health.