HPLC-UV/DAD and ESI-MS(n) analysis of flavonoids and antioxidant activity of an Algerian medicinal plant: Paronychia argentea Lam.

Paronychia argentea Lam., belonging to the Caryophyllaceae family, is a perennial plant widely distributed in Algeria. Even though this plant is used in the Algerian popular medicine, its phytochemical characterization is incomplete. In this study, the flavonoid profile and the in vitro antioxidant activity of the ethanolic extract, decoction and infusion of P. argentea aerial parts are reported. Flavonoids were analyzed by means of high-performance liquid chromatography coupled with diode array detection and electrospray ionization mass spectrometry. Eleven compounds were identified and six of them, including isorhamnetin-3-O-dihexoside, quercetin-3-O-glucoside, quercetinmethylether-O-hexoside, quercetin, jaceosidin and isorhamnetin, were described in this plant for the first time. The ethanol extract showed the highest flavonoid content, followed by the decoction and the infusion (25.4 ± 0.8 mg/g of DM, 8.4 ± 0.5 mg/g of DM, 0.2 mg/g of DM, respectively), while the best antioxidant activity was shown by the decoction (RC0.5 = 178 μg/mL for reducing power, 72.4% of inhibition of lipid peroxidation, IC50 = 27.38μ g/mL for DPPH radical scavenging activity and 59.7% of inhibition of NO radical). These results showed that P. argentea decoction could be considered as a valuable source of flavonoids and antioxidants that might contribute to the valorization of the phytotherapeutic potential of this plant.