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

Characterization of metabolites of sagittatoside B in rats using UPLC-QTOF-MS spectrometry

Sagittatoside B is one of the principal diglucosides in Herba Epimedii. In this work, an ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS) was applied to the rapid analysis of sagittatoside B metabolites in rats after oral administration. A total number of 17 metabolites were detected or tentatively identified from rat plasma, bile, urine and feces. The major metabolic pathways of sagittatoside B in rats were hydrolysis, hydrogenation, hydroxylation, dehydrogenation, demethylation, decarbonylation and conjugation with glucuronic acid and different sugars. This work revealed the metabolism of sagittatoside B in vivo, and reported the characteristic metabolic reactions of sagittatoside B for the first time. This provided the basis for the further research and development of sagittatoside B, and also provided reference for the metabolism of active flavonoid compounds.

Study on the metabolism profile of flavanomarein in Coreopsis tinctoria Nutt

Coreopsis tinctoria Nutt. (family Asteraceae) is a popular medicine-food plant, which improves chronic diseases such as hyperlipemia, hypertension, and diabetes. Flavanomarein is the main active component of Coreopsis tinctoria Nutt, in which the blood concentration of volunteers is low and bioavailability is poor. Thus, the understanding of flavanomarein metabolites and metabolic pathways is significant to clarify its effectiveness. This study systematically studied the metabolites of flavanomarein by oral and injection. The biological samples (feces, urine, and plasma) were analyzed by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry in negative ion mode. The metabolic law of flavanomarein in the liver was further verified by a liver microsomal incubation experiment in vitro. A total of 12 metabolites were identified by oral administration while 15 metabolites were detected by injection. It was shown that metabolic pathways include acetylation, hydroxylation, glucuronidation, methylation, dehydrogenation, etc. The liver extraction rate of flavanomarein was 0.08, which means the metabolic stability of flavanomarein is well in rats' liver microsomes. It is a systematic study on the metabolism of flavanomarein and provides a metabolic rationale for further in-depth in vivo biotransformation. This article is protected by copyright. All rights reserved.

In vivo metabolism of 8,2'-diprenylquercetin 3-methyl ether and the distribution of its metabolites in rats by HPLC-ESI-IT-TOF-MSn

8,2'-Diprenylquercetin 3-methyl ether, a natural product with prominent anti-breast cancer activity, is the main active constituent of Sinopodophylli Fructus. A high-performance liquid chromatography with a diode array detector coupled with electrospray ionization ion trap time-of-flight multistage mass spectrometry (HPLC-DAD-ESI-IT-TOF-MSⁿ) method was established and applied to profile and identify the metabolites of 8,2'-diprenylquercetin 3-methyl ether as well as study their distribution in rat organs for the first time. A total of 100 new metabolites were tentatively identified in rats. The metabolic reactions of 8,2'-diprenylquercetin 3-methyl ether in rats in vivo were hydroxylation, methylation, glucuronidation, dehydrogenation, sulfation, polymerization and cysteine conjugation as well as the specific reactions of leucine/isoleucine, proline, and vitamin C conjugation. The detected metabolites included 77 in faeces, 50 in urine, 11 in plasma, 50 in the small intestine, 32 in the stomach, 23 in the liver, 9 in the lungs, 9 in the spleen, 8 in the heart, and 6 in the kidneys. The results indicated that the small intestine, stomach, and liver were the major organs for the distribution of 8,2'-diprenylquercetin 3-methyl ether metabolites. Furthermore, 27 metabolites showed various bioactivities predicted by the analysis of "PharmMapper", among which 9 metabolites showed anti-cancer activity. These results are very useful for understanding the metabolism and pharmacological actions as well as the effective forms and toxic actions of 8,2'-diprenylquercetin 3-methyl ether in vivo; moreover, they will lay the foundation for further studies on the metabolism of prenylflavonoid compounds.

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

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 CL_int (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 CL_int 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.

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

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.

Chemical Constituents, Quality Control, and Bioactivity of Epimedii Folium (Yinyanghuo)

Epimedii Folium (Yinyanghuo in Chinese) is one of the most commonly used traditional Chinese medicines. Its main active components are flavonoids, which exhibit multiple biological activities, such as promotion of bone formation and sexual function, protection of the nervous system, and prevention of cardiovascular diseases. Flavonoids also show anti-inflammatory and anticancer effects. Various effective methods, including genetic and chemical approaches, have been developed for the quality control of Yinyanghuo. In this review, the studies conducted in the last decade about the chemical constituents, quality control, and bioactivity of Yinyanghuo are summarized and discussed.

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

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.