| Polyphenols,a kind of secondary metabolite with polyphenolic structures,have many biological functions such as antioxidant,antibacterial,anti-cancer and anti-inflammatory.With the development of more and more health food products,many biological functions of plant polyphenols have been widely used by researchers.Studies have found that plant seed coats are rich in phenolic compounds.In industrial production,plant seed coats is often removed and treated as waste,which wastes plant resources.In order to develop and utilize Amygdalus pcdunculata Pall(AP)and Armeniaca Sibirica L.Lam(AS)more effectively,the extraction conditions,component analysis,antioxidant capacity,antibacterial capacity,anti-He PG2 cells,and interaction with protein were studied from polyphenols of Amygdalus pedunculata Pall and Armeniaca Sibirica L.Lamseed coat.The specific contents as follows:1.Extraction of polyphenols.The effect of microwave assisted extraction(MAE),ultrasonic assisted extraction(UAE)and traditional reflux extraction(RE)on the yield of AP and AS seed coat polyphenols was studied.The results showed that MAE had shorter extraction time,lower energy consumption and higher polyphenol yield compared with UAE and RE.Effects of microwave power,extraction time,solvent and solute ratio(S/S),and ethanol concentration on the yield of AP and AS seed coat polyphenol was studied.On this basis,the extraction process of the polyphenols was studied using response surface method(RSM).The results showed that the optimal extraction process of AP seed coat polyphenol was power of 477.70 W,time of 89.12 s,SS of 25.31 m L/g and ethanol of 46.09%.The optimal extraction process of AS seed coat polyphenol was power of 540.00 W,time of 88.68 s,S/S of 25.67 m L/g,and ethanol of 51.35%.The predicted values of total polyphenol content in the AP and AS seed coat were 791.14 ± 2.69 mg /100 g and 885.99 ± 4.26 mg/100 g,respectively.In order to facilitate practical experiment,478.00 W,89.00 s,25.00 m L/g,46.00% as the best extraction process of polyphenols from AP seed coat.At the same time,540.00 W,89 s,26.00 m L/g,51.00% as the best extraction process of AS seed coat polyphenols.The actual experiments validated the yield of polyphenols under the optimum conditions for AP(781.83±3.82 mg/100 g)and AS seed coat(874.49±4.70 mg/100 g).2.Isolation and identification of polyphenols.The polyphenols were purified by organic solvent extraction.The experimental results showed that the purity of polyphenols from AP and AS seed coat was increased by 2.51 times and 2.12 times when using PE as pretreatment reagent,Et OAc as extraction agent,p H 6.The 36 compounds were identified from the AP and AS seed coat polyphenols by LC-ESI/MS,respectively.Apigenin-7-Oglucoside was the highest content of compounds in AP(34.54±1.03 mg/100 g)and AS seed polyphenol(60.47±1.08mg/100 g).In the composition of polyphenols contain apigenin-7-O-glucoside,quercitrin,quercetin,kaempferol,naringenin,phenolic acids and other bioactive compounds.3.Antioxidant activity of polyphenols.The antioxidant activity of polyphenols from AP and AS seed coat was identified through the ability of reducing Fe3+,scavenging ABTS free radicals,OH·,DPPH free radicals,O2×-and H2O2.The result was revealed that AP and AS seed coat polyphenols had high antioxidant capacity,of which the ability of reducing Fe3+,the scavenging capacity of ABTS free radical and H2O2 were stronger than that of the ascorbic acid.In general,antioxidant experiments have shown that polyphenols from AP and AS seed coat have strong antioxidative activity,and the two kinds of seed coat can be used as a source of natural antioxidants.4.Antibacterial activity of polyphenols.First,the inhibitory activities of AP and AS seed coat polyphenols on E.coli,S.aureus,B.subtilis,B.cereus and A.niger were determined by agar diffusion method.The minimum inhibitory concentration(MIC)of two species of seed polyphenols was measured.The result was revealed that AP and AS seed coat polyphenols had high antibacterial ability on E.coli,S.aureus,B.subtilis and B.cereus.The inhibition of AP and AS seed polyphenols on B.subtilis was the strongest(d=17.0±1.4 mm,18.6±0.8 mm,respectively)and were the weakest on E.coli(d=2.6±0.8 mm,13.0±1.4 mm,respectively).Both seed coat polyphenols and tetracycline hydrochloride(THC)showed no inhibitory activity against the fungus A.niger in the experimental concentration range,whereas ampicillin(APC)showed a strong inhibitory activity against the fungus A.niger.The MIC of AP and AS seed polyphenols to E.coli and S.aureus was the same(250.00 mg/m L and 125.00 mg/m L,respectively).The MIC of AP seed coat polyphenol to B.subtilis(62.50 mg/m L)was greater than that of AS seed coat polyphenol(31.25 mg/m L),but the MIC to B.cereus(125.00 mg/m L)was less than that of AS seed coat polyphenol(250.00 mg/m L).5.Anti-Hep G2 cell activity of polyphenols.The inhibition rate on the proliferation and induced apoptosis rate of AP and AS seed polyphenols against Hep G2 cells were measured by MTT method and double staining method,respectively.The result was revealed that AP and AS seed coat polyphenols had a strong inhibitory capacity on the proliferation of Hep G2 cells,and this ability increased with the prolongation of polyphenol concentration and cell action time.Both of the seed coat polyphenols could induce Hep G2 cell apoptosis,and the apoptosis rate of Hep G2 cells exceeded 50% at the maximum concentration of 1000 ?g/m L.6.The interaction of polyphenols with fetal bovine serum albumin.The experimental studied on the interaction of AP and AS seed polyphenols with fetal bovine serum albumen.The experiment was shown that the maximum absorbency of the albumen increases with the concentration of polyphenols.The maximum wavelength of albumen was gradually blue shift when the concentration of polyphenols from AP seed coat gradually increased;the maximum wavelength of the albumen did not change when the concentration of polyphenols from AS seed coat increased gradually.The increase of absorbance value indicates that the action ability of albumen and polyphenol is strengthened with the increase of polyphenol concentration.The blue shift of the wavelength indicates that the conformation of the albumen has changed. |
PDF Full Text Request