Objective: To establish quantitative methods of total diterpene in Caesalpinia minax and optimization of extraction process. Method: The content of total diterpene was determined at 530 nm by vis-spectrophotometry using caesalpinins K as standard and using the color reaction with 5% vanillina-glacial acetic acid and perchloric acid. Result: Linear relationship of caesalpinins K reference solution was good in the range of 2.0-6.1 mg·L-1(r=0.999 5)

the average recovery was 101.8%(RSD 2.3%). Conclusion: The present methods are simple

accurate with good reproducibility

and could be used to control the quality of Caesalpinia minax.