Study On The Chemical Constituents And Biological Activity Of Prunus Avium Seeds

Prunus avium is a deciduous tree native to Europe,cultivated in north-central area in China.The fruits of P.avium are delicious and juicy,showing attractive to consumers due to its taste,sweetness and wealth of nutrients.The fruits,roots,branches,leaves,seeds of P.avium are considered to be a rich source of bioactive natural compounds,which can act as powerful antioxidants agents and reported to have many health promoting activities,including antitumor,anti-inflammatory and antibacterial activities.In this paper,we mainly studied on the chemical profiles of P.avium seeds,including extraction,separation as well as antioxidant and antibacterial activities.Also,we determined the contents of total polysaccharides,total flavonoids,total tannins and total polyphenols from the crude extracts.Meanwhile,the fatty acid composition and the volatile components in P.avium seeds are analysed.In addition,the optimization of the extraction process for flavonoids from P.avium seeds was investigated by using response surface methodology(RSM).Extracted by 95%ethanol at room temperature,crude extracts of P.avium seeds were obtained.Then crude extracts were successively fractionated by n-hexane,CH2C12,EtOAc and n-BuOH on a separation funnel.Three compounds were purified from n-BuOH fraction by column chromatography(CC)and thin layer chromatography(TLC),which were identified as caffeic acid,rutin and apigenin-.7-O-?-D-glucopyranoside by nuclear magnetic resonance(NMR)and mass spectrometry(MS).To determin the contents of compositions of P.avium seeds,we used a variety of colorimetry.The contents of the total polysaccharides,total flavonoids,total tannins and total polyphenols in crude extracts were 7.41%,8.98%,5.07%and 13.82%respectively.After soxhlet extraction and then methyl esterification,the fatty acid compositions were identified by gas chromatography-mass spectrometer(GC-MS)with 22 kinds of fatty acid methyl esters.With steam distillation extraction method,21 compounds were identified in the volatile component by GC-MS.Antioxidant activity was evaluated by two in vitro antioxidant methods,including DPPH and ABTS free radical scavenging protocols.As a whole,EtOAc fraction,n-BuOH fraction and isolated compounds of caffeic acid and rutin showed stronger antioxidant activity.By contrast,the n-hexane and H2O fractions exhibited weaker property.In a certain concentration range,good dose-effect relationship was exhibited.Antimicrobial activity was investigated using cylinder plate method,which was determined against Escherichia coli,Bacillus subtilis,Staphylococous aureus and Salmonella enteric.In the experimental concentration range,results suggested that EtOAc fraction exhibited stronger antibacterial activity.However,CH2Cl2,n-BuOH and crude extracts fractions presented lower properties.The n-hexane and H2O fractions showed barely antibacterial activity.By single factor experiment,combining RSM and considering the limitations of experiments and experimental apparatus,the optimum process conditions were concluded as:extraction temperature 96?,60%(v/v)ethanol concentration,the ratio of liquor to material 30:1 ml/g,extracting time 2.4 h.The actural flavonoids yield of P.avium seeds was 9.4 mg/g by the optimized conditions above,well correspondence with the theoretical value.