The comparison between the laxative effectiveness of Cassia fistula pod pulp extract and Cassia angustifolia in Thai constipated patients
Cassia fistula L. is widely used in Thai folklore medicines for its various medicinal properties. The pulp of ripe pods possesses a mild, pleasant purgative action due to anthraquinone glycosides, the active laxative components. Although the pod has long been used for its laxative effect, no study has been performed to clinically prove its in vivo action. The objective of this randomized crossover, double blind, controlled trial was to compare the laxative effectiveness of C. fistula pod pulp extract to the popular laxative drug from C. angustifolia in patients with constipation. Thirty six Thai participants diagnosed with constipation based on Rome III Criteria  were randomized into 2 groups, the treatment group (n = 17) and the standard group (n = 19). The first group was assigned to have five days of treatment with the control drug, Cassia angustifolia commercial capsules, stop taking the drug for 5 days, and then take the sample drug of C. fistula pod pulp extract capsules for five more days. The second group received the same treatment but in a reversed order. Each patient received 8 capsules of drug before bed time every day and was asked to fill in a daily stool chart. Main outcome measurements included stool frequency and quantity, consistency, ease of evacuation, and adverse effects. In terms of laxative effectiveness of the two types of drugs, there was no significant difference between the two groups (p > 0.05). Taken into consideration of lower anthraquinone content (0.96 mg calculated as rehin) in C. fistula pod pulp than in C. angustifolia product (15 mg calculated as sennoside B), C. fistula should provide more laxative effectiveness than C. angustifolia if the doses of both drugs contained the equal amount of anthraquinone glycosides. Ethnologically, C. fistula pod has long been used as a laxative due to its safety and inexpensiveness, and therefore should be promoted as a commercial laxative drug just like senna.
Keywords: Cassia fistula, laxative, anthraquinone, constipation, rhein, senna
 Rome III Diagnostic Criteria for Functional Gastrointestinal Disorders. (n.d.). Retrieved September 12, 2012, from http://www.romecriteria.org/assets/pdf/19_RomeIII_apA_885 – 898.pdf