Determination of Sennosides A and B in Diet Tea by HPLC

Yaa-Tzy Lin, Cheng-Yeu Huang and Kuo-Ching Wen*

National Laboratories of Foods and Drugs, Department of Health, Executive
Yuan 161-2, Kuen Yang Street, Nankang, Taipei, Taiwan, R.O.C

ABSTRACT

   A rapid high performance liquid chromatographic method was developed for determination of sennosides A and B in senna leaves, pods and diet tea. The determination was carried out by using a gradient elution with acetonitrile and 1% acetic acid on an Inertsil ODS-2 column. The linear calibration ranges of sennosides A and B were 7.52~37.60μg/ml (r=0.9998) and 8.32~49.92μg/ml (r=0.9999), respectively. The recoveries of sennosides A and B were almost quantitative from the senna leaves and pods, respectively. The relative standard deviations of sennosides A and B for intraday and interday analyses were 0.24~1.72% and 0.23~1.71%, respectively. The contents of sennosides A and B in leaves and pods of Cassia angustifolia Vahl have been determined and the results were as follows: sennoside A 0.64, 1.46% and sennoside B 1.57, 2.30%. The contents of sennosides A and B in seven diet tea samples have been determined and the results were as follows: sennoside A 0.10~0.19% and sennoside B 0.16~0.28%.

Key words :senna leaves, senna pods, HPLC, Cassia angustifolia Vahl,sennoside A, sennoside B.