Study On The Structures And Properties Of Quercetin And Some Other Flavonoids

Flavonoids are polyphenolic compounds which widely distributed in plants and abundanted in some foods. These compounds are characterizd by having high biological activities and many pharmacological properties, very useful for the treatment of several disesases. Quercetin is the one of flavonoids owned most biological activities.The pharmacologic values and investigated statues of these compounds were expressed and some electronic stucture about flavonoids molecular were computed with quantum-chemical methods.Then we elucidated roughly the relationship between structure and properties of some flavonoids.In this work, The quercetin oringal model is carried out by semi-empirical method (AM1,MNDO etal.) firstly, optimized by B3LYP/STO-3G//3-21G//6-31G et al. and then deacided using B3LYP/6-31G to get every stability structure.Quercetin is a kind of flavonoids owned many pharmacologic activity. In this work,configurations of quercetin isomers were optimized at the B3LYP/6-31G** level and gained the most stability configuration and some important property. We analyzed that the B ring is the active group of quercetin isomers. The 3-hydroxy restrained the activity of (A+C) rings. Some properties showed that intermolecular hydrogen is formed in this compound. At the same time, we calculated IR for the steadiest configuration, quercetin and the criteria models.Accordingly, we discussed the structure-activity relationship of quercetin.Then based on discribing about the structure and properties of flavonoinds,specially the interactive mechanism and recent reseach advance,the morin catechin and luteolin were caculated at B3LYP/6-31+G^** level. We gained stability configuration of each compound. The caculations show that the electronic distribution, totle energy, frontier molecular orbital energy and caculated IR are related with biological activities of stability configuration.The antioxidant action sites of these flavonoids were analyzed and certified.