| As a natural plant-derived secondary metabolite,stilbene compounds are widely distributed in nature.They are a class of polyphenol compounds with the same 1,2-stilbene core,with complex and diverse structures and antioxidant properties,Antibacterial,cardioprotection,anti-cancer and many other biological activities,its nutritional and health value has attracted people's attention,especially as multiple stilbene compounds have been discovered to have the ability to selectively quench singlet oxygen.The singlet quenching mechanism has also aroused people's interest.Therefore,in this experiment,compounds with different functional group structures were selected to study the singlet oxygen quenching mechanism and compare the differences in the ability of different structures.At the same time,the inhibitory effect of stilbene compounds on Penicillium expansum was preliminarily explored.T he main research results are as follows:1.The early studies on the quenching mechanism of singlet oxygen with resveratrol dimer and resveratrol monomer found that the quenching process of resveratrol,catechol,and carbon-carbon double bonds are all involved in the quenching reaction of singlet oxygen.However,the key structure that plays a decisive role in the quenching of singlet oxygen by stilbene compounds has not yet been determined.In order to explore the key structure of stilbene compounds in quenching singlet oxygen,UHPLC-QTOF-MS2 and UHPLC-QQQ-MS2 were used to analyze and compare resveratrol,dihydroresveratrol,pterostilbene and resveratrol trimethyl ether,piceatannol and oxyresveratrol the physiological activity of quenching singlet oxygen.The results show that the six compounds all exhibit a certain ability to quench singlet oxygen,and their mechanism also proves that resorcinol,catechol,and carbon-carbon double bonds are involved in the quenching reaction of singlet oxygen.Among them,catechol plays a leading role in the quenching of singlet oxygen by resveratrol and its analogs,from strong to weak:catechol>carbon-carbon double bond>resorcinol.2.Further explored the mechanism of resveratrol,dihydroresveratrol,pterostilbene,resveratrol trimethyl ether,piceatannol and oxyresveratrol to protect DNA from singlet oxygen oxidative damage.The UHPLC-QTOF-MS2 and UHPLC-QQQ-MS2 technologies were used to qualitatively monitor and quantitatively analyze the reactants and products in the process of resveratrol dimer protecting guanine from oxidative damage.The results show that the six stilbene compounds can inhibit DNA oxidative damage to varying degrees.The reaction mechanism is that in the presence of stilbene compounds,stilbene compounds will first react with singlet oxygen,thereby reducing the effect of singlet oxygen on guanine.The oxidative damage shows the ability of six stilbene compounds to quench singlet oxygen and protect DNA from oxidative damage.The reaction mechanism is similar to the previous experiment,carbon-carbon double bond,resorcinol,catechol,etc.The structure reacts with singlet oxygen to reduce the content of singlet oxygen,thereby protecting guanine from singlet oxygen oxidative damage.3.The results of stilbene compounds against penicillium expansum showed that resveratrol and pterostilbene had a significant difference in their inhibitory effects on penicillium expansum,and the inhibitory effect of pterostilbene on penicillium expansum was more effective than that of resveratrol strong.In terms of inhibiting the growth of penicillium expansum hyphae,pterostilbene showed inhibitory activity at a lower concentration of 0.2 mM,and as the concentration increased,the inhibition was significantly enhanced,and the effect of resveratrol was weak,and there was no obvious effection at low concentrations.Inhibitory effect both showed a certain ability to inhibit the germination of spores,pterostilbene has a more significant effect.It can inhibit the germination of spores and at the same time inhibit the length of the bud tube.After the treatment of the two compounds,the results of AKP,PI and AO staining of penicillium expansum AKP,AO and PI showed that the two compounds caused certain damage to the cell wall and cell membrane of penicillium expansum,and pterostilbene has the strongest damaging effect.At the same time,after the two compounds were treated,the content of ROS in penicillium expansum was determined,and it was found that the content of ROS increased significantly after treatment,which corresponds to the inhibitory activity of the two com pounds against penicillium expansum. |
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