Characterization of the metabolites of gigantol in rat, dog, monkey, and human hepatocytes using ultra‐high‐performance liquid chromatography coupled with high‐resolution mass spectrometry

Abstract

Rationale: Gigantol (3 0 ,4-dihydroxy-3,5 0 -dimethoxybibenzyl) is a bibenzyl compound isolated from Dendrobii Caulis that has been widely used as a medicinal herb in China. To fully understand the mechanism of action of gigantol, it is necessary to determine its metabolic profile. Methods:Gigantol at a concentration of 20 μM was incubated with hepatocytes (rat, dog, monkey, and human) at 37 C. After 120 min incubation, the samples were analyzed using liquid chromatography coupled with electrospray ionization tandem mass spectrometry. The structures of the metabolites were characterized by their molecular masses, product ions, and retention times. Results:A total of 17 metabolites were detected and structurally identified. The metabolism involved the following pathways: (a) oxidation to form quinone-methide species and subsequently conjugation with glutathione (GSH); (b) demethylation to form demethylated gigantol, which was further conjugated with GSH;(c) hydroxylation to yield hydroxyl-gigantol followed by glucuronidation or GSH conjugation; and (d) glucuronidation to form glucuronide conjugates. Glucuronidation was the primary metabolic pathway in all tested species.Conclusions: Hydroxylation, demethylation, glucuronidation, and GSH conjugation were the major metabolic pathways of gigantol. This study provides new information on the metabolic profiles of gigantol and helps us understand the disposition of the compound.In recent years, there has been increased awareness of the importance of drug metabolism and pharmacokinetics in all stages of drug discovery and development processes not only to further support toxicity or clinical studies but also to optimize drug candidates. [12][13][14] As far as we know, information regarding the metabolism of gigantol is limited. 15 Fan et al identified a total of 11 metabolites of gigantol generated from rat urine using ultra-highperformance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC/ESI-QTOF-MS/MS). 15 This study did provide some metabolic information for gigantol, but the metabolites presented in bile or feces were not identified. It also failed to answer the following questions: (a) whether the identified metabolic pathways were the major pathways of this compound; (b) whether these metabolites presented in humans or other animal species; and (c) whether gigantol displayed species-specific metabolism. Therefore, a systemic metabolism study of gigantol is necessary for better understanding its pharmacokinetic behavior.The aim of this study was (a) to characterize the metabolites of gigantol in different species of hepatocytes using LC/ESI-MS/MS, (b) to propose the metabolic pathways in hepatocytes, and (c) to disclose the species difference in metabolism. To the best of our knowledge, this is the first study of the in vitro metabolism of gigantol, and it provides new information regarding its metabolic profiles, which helps us understand its pharmacokinetic behavior as well that of other bibenzyl ...

High‐resolution mass spectrometry‐based methodology for the identification of the metabolites of pterostilbene produced by rat, dog and human hepatocytes

“…The metabolism of stilbenoids has been extensively investigated in previous studies, such as resveratrol (Gambini et al, 2015), erianin (Liu et al, 2020), dihydroresveratrol (Ji et al, 2021) and gigantol (Fan et al, 2014; Wang et al, 2020). Compared with previous studies, pterostilbene showed similar metabolic pathways to other stilbenoids, i.e.…”

“…glucuronidation was the most predominant metabolic pathway. In addition, like erianin (Liu et al, 2020), dihydroresveratrol (Ji et al, 2021) and gigantol (Wang et al, 2020), GSH conjugation (M5 and M6) was also found to be one of the metabolic pathways, suggesting the formation of reactive metabolite. Reactive metabolite has been recognized as one of the causative factors of some drug toxicity.…”

Detection and structural characterization of the metabolites of dihydroresveratrol in rats by liquid chromatography coupled to high‐resolution tandem mass spectrometry

“…In previous studies, the metabolism of several stilbenoids has been investigated, including resveratrol, 18,19 erianin 17 and gigantol. 20 The major metabolic pathways of resveratrol were glucuronidation and sulfation. In addition, resveratrol could be metabolized into dihydroresveratrol in human intestinal bacteria.…”

Identification and characterization of the in vitro metabolites of batatasin III by liquid chromatography in combination with Orbitrap mass spectrometry

“…11,12 The development of high-resolution mass spectrometry has facilitated metabolite identification, which can provide structure-associated information of the parent and metabolites. [13][14][15] There are several publications regarding studies of the metabolism of stilbenoids such as gigantol 16 and erianin .17 To the best of our knowledge, the metabolic fates of batatasin III have not been discovered.…”