Abstract: The extraction conditions of kaempferol were optimized by a two-phase acid hydrolysis method,  and the effects of acid concentration,  extraction time and solid-liquid ratio on the extraction yield of kaempferol were investigated by a single factor experiment combined with high performance liquid chromatography (HPLC). The  response surface Box-Behnken experiment was used to optimize the extraction process of kaempferol. The experimental results show that the optimum extraction conditions are  the concentration of hydrochloric acid of 6.1×10^-2 mmol/L,  the extraction time of 12.87 min,  the solid-liquid  ratio of 1∶137.46,  and the extraction yield is 1.11%. Kaempferol has a certain antioxidant effect,  and has certain scavenging ability on superoxide free radical (·O^2-) and 1,1-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH·),  especially on DPPH·,  and the scavenging ability  increases with the increase of concentration.

Key words: kaempferol, acid hydrolysis,  , response surface method, biochemical property,  , antioxidant