HPLC and HPLC-MS Analysis of Intestinal Elimination and Phase 2 Metabolism of 4'-hydroxy-4-Methoxychalcone and its Bis-Mannich Analog In The Rat

Aims: The aim was to study the elimination and Phase 2 biotransformation of 4'-hydroxy-4-methoxychalcone (1) and its bis-Mannich analog (2) in the small intestine of the rat. Background: Earlier studies indicated that chalcones are promising starting points for drug design. Aminomethylation of drugs is considered to improve their delivery into the human body. Objectives: To set up validated HPLC-UV methods to quantitate the investigated chalcones in the rat intestinal perfusates. Comparison of intestinal disappearance and Phase 2 metabolic profile of the 4’-hydroxychalcone (1) and a bis-Mannich analog (2). Methods: Chalcones 1 and 2 were luminally perfused in the small intestine of rats at a concentration of 240 μM and 280 μM, respectively. Analysis of the collected intestinal perfusate samples was performed by a validated HPLC-UV method. Using HPLC-MS, the samples were analyzed for Phase 2 metabolites as well. Results: Elimination kinetics of the two 4’-hydroxychalcones displayed characteristic differences having the nonpolar chalcone 1 higher elimination rate over the 90-minute ex vivo experiments. HPLC-MS analysis of the perfusates indicated the presence of glucuronide, sulfate, and glutathione conjugates in the parent molecules. Intestinal disappearance and sulfation of the bis-Mannich derivative 2 showed characteristic differences compared to 1 Conclusion: The results demonstrate, to the best of our knowledge, for the first time, how the title structural modification of phenolic chalcones affects intestinal elimination and Phase 2 metabolism of the compounds Highlights: Study on ex vivo intestinal elimination of a 4'-hydroxy-4-methoxychalcone and its bis-Mannich analog. Development of validated HPLC-UV methods for quantitation of 4’-hydroxychalcone derivatives in rat intestinal perfusates. HPLC-MS identification of Phase 2 metabolites of 4’-hydroxychalcones in rat intestinal perfusates.