Study On The Chemical Compounds And Antioxidant Activities Of Water Extract From Allium Tenuissimum Flowers

Allium tenuissimum belongs to Allium plants in liliaceae,the top of the inflorescence can be used for condiments and was popular with people in the north of China because of its rich fragrance especially after fried.So far,the chemical composition and antioxidant activities related Allium tenuissimum flowers(ATFs)were less studied,which restricted the development and application of its related products.Therefore,the study on chemical composition and properties of Allium tenuissimum flowers can provide theoretical basis for its further development.In this paper,the method using head space solid phase micro-extraction and gas chromatography-mass spectrometry(HS-SPME-GC-MS)was developed for determination volatile components of water extract from ATFs and non-volatile chemical components in the water extracts were analyzed using high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(HPLC-Q-TOF-MS).In addition,the antioxidant activities and inhibitory on nitrosation were also studied.The main research contents and conclusions are as follows:(1)Analysis of volatile components in water extractVolatile components were enriched using five different solid-phase micro-extraction and separated,identified by two different polarity of chromatographic columns.On this base,methods that analyze volatile components of water extract from Allium tenuissimum flowers through HS-SPME-GC-MS were established.The results showed that 152 volatile components were identified,including 12 sulfur compounds,15 alcohols,11 ketones,12 aldehydes,8 acids,30 esters,7 phenols,9 aromatics,40 hydrocarbons,3 ethers and 5 others.Furthermore,reveals the main flavor components were 1,3-dithiane,dimethyl sulfide,dimethyl disulfide,methyl propyl disulfide,2,5-dimethylthiophene,3,4-dimethylthiophene,2-Methoxy-4-vinylphenol,decanoic acid,benzaldehyde,phenylacetaldehyde,butylated hyfroxyanisole,dihydroactinidiolide,lauric acid,etc.(2)Analysis of non-volatile chemical composition of water extract from Allium tenuissimum flowersSeparation conditions of non-volatile compounds of water extract from Allium tenuissimum flowers are selected through liquid chromatography and on this basis,these constructions about chemical compounds were analyzed by HPLC-Q-TOF-MS.Finally,5 compounds are identified,including tetrahydrocolumbamine,Kaempferol Acetyl hexose,Kaempferol-3,7-diglucoside,Kaempferol-3-O-glucoside,Quercetin-3-glucoside-7-Orhamnoside and all are reported for first time.(3)Study on antioxidant properties and inhibitory on nitrosation of water extractThe main bioavtive compounds were determined using colorimetry;Antioxidant activity of water extract from Allium tenuissimum flowers were determined by four evaluation methods in vitro(DPPH×;ABTS+×;hydroxy free radical;reducing power)and three evaluation methods in vivo(Glutathione peroxidase,GSH-Px;Superoxide dismutase,SOD;Malondialdehyde,MDA);In simulated gastric environment(pH 3.0,temperature 37?),scavenging activities on nitrite and inhibiting activities on N-nitrosamine formation were exzamined.The results showed that Using water as solvent,the bioactive components in Allium tenuissimum flowers could be effectively extracted,total sugar content was 50.32±1.23 mg/g,reducing sugar content was 30.33 ± 0.05 mg/g,total phenol content was 4.59 ± 0.56 mg/g,and total flavonoids content was 2.60 ± 0.78 mg/g;Allium tenuissimum flowers had great scavenging capacity on different free radical and were dose-dependent with its mass concentration.What's more,mice's diet intervented by water extract from ATFs could significantly increase GSH-Px?SOD activity and reduce MDA content and the concentration was the higher,the effect was the better;In simulated gastric environment,water extract presented great scavenging activity on nitrite and inhibiting activity on formation of N-nitrosamines.Its concentration and reaction time werepositively correlated to nitrite scavenging capacity and N-nitrosamines formation inhibitory.When the concentration was 10mg/mL and the reaction time was 30 min,the scavenging capacity of nitrite of water extract was 75.44 % and the inhibition rate of N-nitrosamine synthesis was up to 90.27 %.To sum up,the water extract of Allium tenuissimum flowers has certain antioxidant capacity and can inhibit on nitrosation,providing theoretical reference for the development of Allium tenuissimum flowers as natural antioxidants and related products.