Pharmacokinetics andmetabolites of glycosides and lignans of the stem bark of Magnolia officinalis in functional dyspepsia and normal rats using liquid chromatography-tandem mass spectrometry

The stem bark of Magnolia officinalis is a traditional Chinese medicine for the treatment of abdominal distention and functional dyspepsia. The pharmacokinetics of three glycosides (magnoloside A, magnoloside B, and syringin) and two lignans (honokiol and magnolol) in both normal and functional dyspepsia rats were firstly investigated by ultra-performance liquid chromatography-triple quadrupole mass spectrometry method and the influences of the coexisting compounds on the pharmacokinetic parameters of honokiol and magnolol were also studied. It was found that all of the five target compounds were quickly absorbed and eliminated in both normal and functional dyspepsia rats, while, their residence time was significantly decreased in pathological states except magnoloside A. The coexisting compounds in the stem bark of M. officinalis significantly reduced absorption and increased elimination of honokiol in vivo. It's worth noticing that the volume of distribution of lignan was quite lower than that of a glycoside. Moreover, the metabolic profiling of magnoloside A, honokiol, and magnolol in vivo was analyzed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry method, from which three prototypes were identified and 35 metabolites were putatively characterized, and 18 unknown metabolites were reasonably characterized for the first time. The results indicated that sulfation and glucuronidationwere the main metabolic pathways of honokiol and magnolol.

Automated summary

This study investigated the pharmacokinetics of five compounds in the stem bark of Magnolia officinalis in both normal and functional dyspepsia rats. The results showed that the residence time of these compounds was significantly decreased in pathological states, except for one compound. The coexisting compounds in the stem bark affected the absorption and elimination of honokiol in vivo. Metabolic profiling analysis identified three prototypes and characterized 35 metabolites, including 18 unknown metabolites.