Stability of barakol under hydrolytic stress conditions and its major degradation product.
The aim of the present study was to investigate the stability of barakol, an anxiolytic constituent extracted from leaves of Senna siamea (Lam.) Irwin & Barneby (syn. Cassia siamea Lam.), under the International Conference on Harmonisation suggested conditions using HPLC with photodiode array detection. Extensive degradation of barakol was found to occur under alkaline conditions through base-catalyzed hydrolysis. Mild degradation of barakol was observed under thermal and oxidative stress while it was stable under acidic conditions. The reaction rate constants (Kobs) of barakol degradation under alkaline conditions at pHs 12 and 13 were 3.0x10(-5) and 9.6x10(-3) min(-1), respectively. The activation energy according to the Arrhenius plot was calculated to be 26.9+/-3.3 kcal/mol at pH 13 and temperatures between 12 and 51 degrees C. The major degradation product of barakol under both alkaline and thermal stress conditions was characterized by LC-MS and NMR as cassiachromone.
Chantong
Boonrat
B
Faculty of Veterinary Sciences, Mahidol University, Nakornpathom, Thailand.
Wongtongtair
Supim
S
Nusuetrong
Punnee
P
Sotanaphun
Uthai
U
Chaichantipyuth
Chaiyo
C
Meksuriyen
Duangdeun
D
D014151:Anti-Anxiety Agents / Q000737:chemistry*; D001578:Benzopyrans / Q000737:chemistry*; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D015394:Molecular Structure; D043803:Phenalenes / Q000737:chemistry*; D029846:Senna Plant / Q000737:chemistry; D013696:Temperature
D014151:Anti-Anxiety Agents; D001578:Benzopyrans; D043803:Phenalenes; C107911:barakol