Abstract:Antioxidant and inhibitory effect on N-nitrosation of Allium tenuissimum flowers extracts were studied.Four various polar solvents（water，95%ethanol，ethyl acetate，petroleum ether）were used to extract compounds from Allium tenuissimum flowers.In addition，the content of bioactive compounds，antioxidant properties and inhibitory effect on N-nitrosation of extracts were investigated.The results showed that total sugar content（TSC），reducing sugar content（RSC）which were highest in water extract，were （50.32±1.23）and（30.33±0.05）mg/g，respectively.While total phenolics content（TPC），total flavonoids content（TFC）which were highest in 95%ethanol extract，were （11.80±1.09），（12.65±0.85）mg/g，respectively.The effects of scavenge free radical induding DPPH，ABTS+and total reducing power were best in water extract.In simulated gastric environment in vitro（pH 3.0，temperature 37℃），each extracts could effectively scavenge nitrite and inhibit N-nitrosames formation，and presented an increasing trend with the increase of concentration and reaction time，in which water extract showed that nitrite scavenging activity and inhibitory activity of N-nitrosamines formation were best.The results indicated that Allium tenuissimum flowers had good antioxidant activity and inhibitory effect on nitrosation，which would provide the scientific theory basis for antioxidants research and new anti-cancer drug research.