The seasonal dynamics of the total flavonoid contents in various parts of Dryopteris erythrosora , a traditional Chinese medicinal fern, and their antioxidant activity were investigated. The total flavonoids content in various parts of D. erythrosora showed an obvious seasonal dynamic change. The total flavonoid contents in stems (from 4.3% to 12.5%) were much higher than that in leaves with an average content of 2.01%. In spring, the total flavonoid contents in stems were relatively low, but increased rapidly from summer to winter. However, the seasonal dynamics of total flavonoid contents in leaves showed different model. The total flavonoid contents in the stems showed a negative correlation with that in the leaves from January to July. The correlation coefficient of about −0.7 was obtained. The antioxidant activity of the extracts also altered in proportion to the change of total flavonoid contents. In general, the extracts from stems always showed highest antioxidant potentials and it was suggested that the stems can be used as crude medicine.
Yanni Cao,Shengzuo Fang,Xiangxiang Fu,Xulan Shang,Wanxia Yang
Cyclocarya paliurus(Batal.) Iljinskaja is a plant with nutraceutical importance since its leaves have been used historically as folk medicines for hundreds of years. The content of 10 phenolic compounds was determined throughout the growing season by high-performance liquid chromatography (HPLC) with UV detector, while the antioxidant activities ofC. paliurusleaf extracts were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical cation (ABTS), and ferric reducing antioxidant power (FRAP) methods. Seasonal variations in phenolic concentration and antioxidant activity as well as linkage between the phenolic composition and antioxidant activity were assessed. A significant seasonal variation of phenolic compounds was observed in the leaves and the highest content appeared in May, July, and November. Seventy percent ethanol extract ofC. paliurusleaves possessed a good radical scavenging potency. Meanwhile, a significant correlation between antioxidant activities and contents of phenolics was detected. Results of the relationship between molecular structures and their antioxidant activities showed that both the number and configuration of H-donating hydroxyl groups are the main structural features influencing the antioxidant capacity of phenolics, while glycosylation may reduce the antioxidant capacity. The information provided by this study not only revealed the accumulative dynamics of phenolic compounds, but also established a basis for determining the optimal time for harvesting to improve the content of beneficial compounds in the leaves ofC. paliurusin the future.Keywords:Cyclocarya paliurus;seasonal dynamic;phenolic acids;flavonoids;antioxidant activity;structure-activity relationship
危险品化学品经营许可证（带存储）