Identification of Metabolites of Epimedin A in Rats Using UPLC/Q–TOF–MS

Chen

Journal of Analytical Methods in Chemistry

et al. 2017

Icaritin is a naturally bioactive flavonoid with several significant effects. This study aimed to clarify the metabolite profiling, pharmacokinetics, and glucuronidation of icaritin in rats. An ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS) assay was developed and validated for qualitative and quantitative analysis of icaritin. Glucuronidation rates were determined by incubating icaritin with uridine diphosphate glucuronic acid- (UDPGA-) supplemented microsomes. Kinetic parameters were derived by appropriate model fitting. A total of 30 metabolites were identified or tentatively characterized in rat biosamples based on retention times and characteristic fragmentations, following proposed metabolic pathway which was summarized. Additionally, the pharmacokinetics parameters were investigated after oral administration of icaritin. Moreover, icaritin glucuronidation in rat liver microsomes was efficient with CLint (the intrinsic clearance) values of 1.12 and 1.56 mL/min/mg for icaritin-3-O-glucuronide and icaritin-7-O-glucuronide, respectively. Similarly, the CLint values of icaritin-3-O-glucuronide and icaritin-7-O-glucuronide in rat intestine microsomes (RIM) were 1.45 and 0.86 mL/min/mg, respectively. Taken altogether, dehydrogenation at isopentenyl group and glycosylation and glucuronidation at the aglycone were main biotransformation process in vivo. The general tendency was that icaritin was transformed to glucuronide conjugates to be excreted from rat organism. In conclusion, these results would improve our understanding of metabolic fate of icaritin in vivo.

Section: Introductionmentioning

confidence: 99%

Metabolite Profiling, Pharmacokinetics, and In Vitro Glucuronidation of Icaritin in Rats by Ultra-Performance Liquid Chromatography Coupled with Mass Spectrometry

Chen

Journal of Analytical Methods in Chemistry

et al. 2017

“…Based on these data, they were characterized as mono-glucuronide of icaritin. On the basis of previous study (Cui et al, 2014; Jin et al, 2013), icaritin-3- O -glucuronide, icaritin-7- O -glucuronide and icaritin-5- O -glucuronide were eluted successively on a reverse C18 chromatographic column. So, G1, G2 and G3 were characterized as icaritin-3- O -glucuronide, icaritin-7-O-glucuronide and icaritin-5- O -glucuronide, respectively (Figure 1c).…”

Section: Resultsmentioning

confidence: 99%

“…Icaritin is a natural flavonoid isolated from Herba Epimedii with multiple biological properties. It was shown that icaritin could be rapidly metabolized to phase II glucuronide conjugates and extensive glucuronidation conjugates were detected in rat urine samples after oral administration of individual prenylflavonoids or Herba Epimedii extracts (Chang et al, 2012; Cui et al, 2014; Jin et al, 2013; Zhao et al, 2010). Hence, it was speculated that glucuronidation reaction played an important role for icaritin clearance and determining its body exposure (bioavailability).…”

Section: Discussionmentioning

confidence: 99%

“…Meanwhile, it is shown that epimedium flavonoids could be hydrolyzed into secondary glycosides or aglycone by intestinal flora or enzymes, thereby enhancing their absorption and antiosteoporosis activity (Zhou et al, 2015). As so far, numerous researches of prenylflavonoids or individual flavonoid had been conducted in the fields of in vivo metabolites profiling (Chang et al, 2012; Cui et al, 2014; Jin et al, 2013; Qian et al, 2012; Zhao et al, 2010). Icaritin, as an intermediate aglycone, is easily metabolized and transformed into high polar conjugates to be preferentially excreted from the rat organism (Wang et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…Icaritin, as an intermediate aglycone, is easily metabolized and transformed into high polar conjugates to be preferentially excreted from the rat organism (Wang et al, 2015). Icaritin-3- O -glucuronide, icaritin-7- O -glucuronide and icaritin-5- O -glucuronide were the main Phase II conjugates, which indicated that glucuronidation is considered as the main clearance pathway for icaritin metabolism (Cui et al, 2014; Jin et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Glucuronidation of icaritin by human liver microsomes, human intestine microsomes and expressed UDP-glucuronosyltransferase enzymes: identification of UGT1A3, 1A9 and 2B7 as the main contributing enzymes

et al. 2017

1. Icaritin is a natural flavonoid with anti-osteoporosis activity. This study aimed to characterize icaritin glucuronidation by pooled human liver microsomes (HLM) and pooled human intestine microsomes (HIM), and to determine the contribution of individual UDP-glucuronosyltrans-ferase (UGT) enzyme to icaritin glucuronidation. 2. Glucuronidation rates were determined by incubating icaritin with uridine diphosphate glucuronic acid (UDPGA)-supplemented microsomes. Kinetic parameters were derived by appropriate model fitting. Relative activity factors and activity correlation analysis were performed to identify main UGT isoforms. 3. UGT1A3, 1A7, 1A8, 1A9 and 2B7 were mainly responsible for catalyzing the formation of two glucuronides (G1 and G2). Icaritin 3-O-glucuronidation (G1) was significantly correlated with Chenodeoxycholic acid (CDCA) glucuronidation (r = 0.787, p = 0.002), propofol glucuronidation (r = 0.661, p = 0.019) and Zidovudine (AZT) glucuronidation (r = 0.805, p = 0.002). Similarly, icaritin 7-O-glucuronidation (G2) was also correlated with CDCA glucuronidation (r = 0.640, p = 0.025), propofol glucuronidation (r = 0.592, p = 0.043) and AZT glucuronidation (r = 0.661, p = 0.019). In addition, UGT1A3, 1A9 and 2B7 contributed 37.5, 33.8 and 21.3% for G1 in pooled HLM, respectively. Also, UGT1A3, 1A9 and 2B7 contributed 34.3, 20.0 and 8.6% for G2 in pooled HLM, respectively. 4. Icaritin was subjected to significant glucuronidation, wherein UGT1A3, 1A7, 1A8, 1A9 and 2B7 were main contributing enzymes.

Biomedical Chromatography

The profiling and identification of the metabolites of 8‐prenylkaempferol and a study on their distribution in rats by high‐performance liquid chromatography with diode array detection combined with electrospray ionization ion trap time‐of‐flight multistage mass spectrometry

et al. 2015

8-Prenylkaempferol is a prenylflavonoid that has various bioactivities and benefits for human health. A high-performance liquid chromatography with a diode array detector combined with electrospray ionization ion trap time-of-flight multistage mass spectrometry (HPLC-DAD-ESI-IT-TOF-MS(n) ) method was established to profile and identify the metabolites of 8-prenylkaempferol in rat in vivo and in vitro, and to study the distribution of these metabolites in rats for the first time. A total of 38 metabolites were detected and tentatively identified, 30 of which were identified as new compounds. The new in vivo metabolic reactions in rats of prenylflavonoids of isomerization, polymerization, sulfation, amino acid conjugation, vitamin C conjugation and other known metabolic reactions were found in the metabolism of 8-prenylkaempferol. The numbers of detected metabolites in feces, urine, plasma, small intestine, stomach, kidneys, liver, heart, lungs, spleen and hepatic S9 fraction were 31, 19, 1, 20, 13, 8, 7, 3, 3, 1 and 11, respectively. This indicated that small intestine and stomach were the major organs in which the 8-prenylkaempferol metabolites were distributed. Furthermore, 16 metabolites were determined to have bioactivities based on the literature and 'PharmMapper' analysis. These findings are useful for better comprehension of the effective forms, target organs and pharmacological actions of 8-prenylkaempferol. Moreover, they provide a reference for the study of the metabolism and distribution of prenylflavonoid aglycone compounds.