Abstract:

In this study，phenolics content and antioxidant activity of （Juglans sigillata Dode.‘Qianhe 7’）leaves in vitro were analysis at 9 developmental stages. The results showed that phenolics content presented a trend of bimodal curve during the annual growing period. It increased from April 12 to May 11，then decreased until July 6 and increased rapidly again until August 1. Subsequently，phenolics content gradually reduced until September 19. Twelve kinds of monophenols，including gallic acid，catechin，chlorogenic acid，caffeic acid，syringic acid，syringaldehyde，p-coumaric acid，ferulic acid，rutin，myricetin，quercetin and juglone，were identified by HPLC method，in which rutin was observed at the highest content，followed by chlorogenic acid. Contents of p-coumaric acid and gallic acid were in lower levels，respectively. Most of monophenols decreased in May，but part of them increased in August. Both total phenolics and total flavones contents highly correlated with antioxidant activity as determined by FRAP or ABTS methods，respectively，while lower correlations between monophenols and antioxidant activities was observed in this study. Walnut leaves are rich in ，which lead to strong antioxidant activity. Phenolics content and antioxidant activity changed regularly with development of walnut leaves and variation of environment.phenolics contentwalnut

Key words: walnut, Juglans sigillata, leaf, phenolics, monophenols, antioxidant activity, correlation