Abstract: Four species of bamboo were studied in our research.The crude protein,ether extract,crude fiber,ash,nitrogen free extract,calcium,total phosphorus,and flavones of four kinds of bamboo leaves were analyzed in this study.The antioxidant ability of flavonoid extracts from bamboo leaves were evaluated by DPPH,ABTS free radical scavenging rate,ferrous reduction ability and metal chelating ability.The crude protein content of Neosinocalamus rectocuneatus was the highest and Bambusa multiplexwas the lowest.The ether extract was highest in Bambusa multiplex,Neosinocalamus rectocuneatus was the lowest.The crude fibre Bambusa multiplex was the highest.The Neosinocalamus rectocuneatus was the lowest.The calcium of Phyllostachys sulphurea was the highest,and the Bambusa multiplex was the lowest.Flavonoid of Bambusa multiplex was the highest and Phyllostachys sulphurea was the lowest.Among the four kinds of bamboo leaf flavonoid extracts,Phyllostachys sulphurea leaf extract had the best scavenging effect on DPPH free radicals.The scavenging effect of Bambusa multiplex flavonoid extract on DPPH free radicals was similar to that of BHT.The order of ABTS free radical scavenging ability were BHT > Neosinocalamus rectocuneatus> Phyllostachys sulphurea> Phyllostachys nigra> Bambusa multiplex.Ferrous reduction ability of four flavonoid extracts from bamboo leaves was stronger than that of BHT,while metal chelating ability was lower than that of EDTA.The correlation analysis between flavonoid content and antioxidant activity showed that there was a significant positive correlation between flavonoid and ABTS free radical scavenging,while there was no significant positive correlation between flavonoid and DPPH free radical scavenging and FRAP free radical scavenging.The results showed that flavonoid extracts from Phyllostachys sulphurea and Neosinocalamus rectocuneatus had strong antioxidant activity in vitro.

Key words: bamboo leaves, nutritional components, flavonoid extracts, antioxidant activity