Fingerprinting profile of flavonol glycosides from Bassia eriophora using negative electrospray ionization, computational studies and their antioxidant activities

•Phytochemical analyses of halophytic Bassia eriophora was performed by LC-ESI-MSn.•Structures of phenolic compounds were deduced according their ion fragmentation.•Experimental and computational antioxidant studies were performed. A total of twenty-eight flavonol glycosides and one alkaloidal metabolite have been detected in 40% MeOH portion after eluting the crude extract from the aerial parts of Bassia eriophora on C-18 short column. These compounds were tentatively detected by using LC–ESI-MS/MS in negative ion mode [M–H]– and represented two major categories: acylated and non-acylated flavonol glycosides. Obtained data indicated that Bassia eriophora is a rich new source of flavonol glycosides. Selected compounds were studied by DFT and TD-DFT calculations to determine their physico-chemical properties and their antioxidant activity. B. eriophora exhibited high TAC, RP and DPPH radical scavenging activity with IC50 of 177.8 µg/mL. Moreover, reducing power at 5 µg/ml and TAC at 5 µg/ml of B. eriophora showed a positive correlation with total flavonoids. The present results may open an avenue to exploit B. eriophora in pharmaceutical applications.