Liquid chromatography-three-dimensional mass spectrometry enables confirmative structural annotation of cistanoside F metabolites in rat.

Clarification the existence forms, including prototype and metabolite(s) is the prerequisite for understanding in-depth the therapeutic mechanisms of a given agent, particularly when oral administration. However, it is still a long distance for unambiguous structural identification of metabolites even employing the cutting-edge MS/MS technique, and the determinant obstacle is produced by its inherent isomer-blind disadvantage. To tackle with this drawback, online energy-resolved mass spectrometry (online ER-MS) was introduced to enable isomeric discrimination after that high-resolution MS/MS provided empirical molecular formula as well as substructures. In-depth metabolic characterization of cistanoside F (CF), an effective natural product, was conducted as a proof-of-concept for the new strategy namely three-dimensional MS that was configured by MS1, MS2 and online ER-MS as 1st, 2nd, and 3rd dimensions, respectively. Sensitive metabolite detection was assisted by predictive multiple-reaction monitoring function on Qtrap-MS, and the empirical formulas of all metabolites were calculated from the quasi-molecular ions yielded from IT-TOF-MS. Subsequently, substructures of each metabolite were constructed by combining the calculated element compositions and the well-defined mass fragmentation pathways. Finally, online ER-MS was responsible to generate optimal collision energies for bonds-of-interest, and enabled rational selection among candidate structures. A total of thirteen metabolites were detected and confirmatively identified in rat after oral treatment of CF using LC-3D MS. Acyl-migration, hydrolysis and sulfation played key roles for the metabolic fate of CF. More importantly, LC-3D MS is an eligible tool to achieve confidence-enhanced structural annotation of metabolites in biological matrices because of the unique isomeric differentiation ability from online ER-MS.

Comparative metabolism of schaftoside in healthy and calcium oxalate kidney stone rats by UHPLC-Q-TOF-MS/MS method.

Schaftoside is a flavone-C-glycoside isolated from Herba Desmodii Styracifolii with valuable anti-kidney stones efficacies. In this study, a six-step strategy was first developed to detect and identify the metabolites in plasma, urine, bile, feces and rat intestinal bacteria samples of healthy and model rats administrated with schaftoside using ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS). The number and the relative peak area of metabolites in healthy rats and model rats were compared, and it was noticed that metabolites in bio-samples of healthy and model rats both had obvious differences. A total of 28 metabolites of schaftoside in healthy rats and 30 metabolites in model rats were initially indentified. The relative peak area of the parent drug and every metabolite in model rat plasma samples were larger than those in healthy rat plasma. Those metabolites with high blood concentrations might be beneficial for the treatment of calcium oxalate stones in the kidney. The results are valuable and important for understanding the metabolic process of schaftoside in clinical application, and especially the metabolism study in calcium oxalate kidney stone model rats could provide a beneficial reference for the further search of effective substances associated with the treatment of kidney stones.

Simultaneous determination of seven effective components of Tripterygium glycosides in human biological matrices by ultra performance liquid chromatography-triple quadrupole mass spectrometry.

This paper developed a novel, sensitive, and selective ultra-performance liquid chromatography-triple quad mass spectrometry method to simultaneously determine seven effective constituents (triptolide, triptophenolide, celastrol, wilforgine, wilforine, wilfordine and wilfortrine) of Tripterygium glycosides (GTW) in human serum and urine. The chromatographic separation was performed on the C18 column using an ammonium acetate buffer solution-acetonitrile (both containing 0.1% formic acid) in a gradient program with a flow rate of 0.3 mL/min. Monitoring reaction mode was applied to target compounds quantitative analysis in the positive electrospray ionization (ESI) mode. The analysis process took 11 min in total. This method was fully validated with a linear range of 1-200 ng/mL for triptolide, 0.4-80 ng/mL for celastrol, 0.1-20 ng/mL for triptophenolide, wilforgine, wilforine, wilfordine, and wilfortrine. The intra-day and inter-day accuracy and precision of the target compounds all met the 15% criterion in both serum and urine. Extraction recovery, matrix effect, and dilution integrity were also validated. The short-term and long-term stability results indicated that all the constituents were stable in human serum and urine under the investigated storage conditions. 10 patients' specimens were collected and analyzed. Most of the compounds exhibited the tendency of higher concentration in urine than that in serum. The concentration that was detected in the serum and in the urine of alkaloids showed a positive-correlation property. This is the first time that triptophenolide was quantified in human bio-matrices. The method is feasible for multi-components therapeutic monitoring or pharmacokinetics study in clinical pharmaceutical research of Tripterygium glycosides.

UPLC-Q-TOF-MS and UPLC-MS/MS methods for metabolism profiles and pharmacokinetics of major compounds in Xuanmai Ganjie Granules.

Xuanmai Ganjie Granules (XMGJ), a widely used Chinese herbal formula in the clinic, is used for treatment of sore throats and coughs. Despite the chemical constituents having been clarifying by our previous studies, both of the metabolism and pharmacokinetic studies of XMGJ are unclear. This study aimed to explore the disposition process of XMGJ in vivo. A sensitive and selective ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) method was developed to analyze the absorbed components and metabolites in rat plasma and urine after oral administration of XMGJ. A total of 42 absorbed components, including 16 prototype compounds and 26 metabolites, were identified or tentatively characterized in rat plasma and urine after oral administration of XMGJ. Moreover, the pharmacokinetic studies of five compounds of XMGJ were investigated using ultra-high liquid chromatography with tandem mass spectrometry method. The results indicated that liquiritin, harpagoside, glycyrrhetic acid, liquiritigenin, formononetin and their metabolites might be the major components involved in the pharmacokinetic and metabolism process of XMGJ. This research showed a comprehensive investigation of XMGJ in vivo, which could provide a meaningful basis for further material basis and pharmacological as well as toxicological research.

Identification of poliumoside metabolites in rat plasma, urine, bile, and intestinal bacteria with UPLC/Q-TOF-MS.

Poliumoside is representative of phenylethanoid glycosides, which are widely found in many plants. Poliumoside is also regarded as the main active component of Callicarpa kwangtungensis Chun (CK), though its oral bioavailability in rat is extremely low (0.69%) and its in vivo and in vitro metabolism has not yet been systematically investigated. In the present study, an ultra performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) method was employed to identify the metabolites and investigate the metabolic pathways of poliumoside in rat after oral administration 1.5 g·kg-1 of poliumoside. As a result, a total of 34 metabolites (30 from urine, 17 from plasma, and 4 from bile) and 9 possible metabolic pathways (rearrangment, reduction, hydration, hydrolyzation, dehydration, methylation, hydroxylation, acetylation, and sulfation) were proposed in vivo. The main metabolite, acteoside, was quantified after incubated with rat intestinal bacteria in vitro. In conclusion, the present study systematically explored the metabolites of poliumoside in vivo and in vitro, proposing metabolic pathways that may be significant for further metabolic studies of poliumoside.

UPLC-Q-TOF/MS-based metabolic profiling comparison of four major bioactive components in normal and CKD rat plasma, urine and feces following oral administration of Cornus officinalis Sieb and Rehmannia glutinosa Libosch herb couple extract.

Cornus officinalis-Rehmannia glutinosa herb couple is widely used herb medicine in clinical practice to treat chronic kidney disease (CKD). However, the in vivo integrated metabolism of its main bioactive components in CKD rats remains unknown. In this study, UPLC-Q-TOF/MS technique combined with Metabolynx™ software, was developed and successfully applied for analysis of metabolic profiles of the bioactive components of the herb couple in normal and CKD rat biological samples. Main parent components of the herb couple extract such as loganin, morroniside and catalpol were absorbed into the blood circulation of the normal and CKD rats. Another parent component acteoside was almost completely degraded. Seventeen metabolites involved in the in vivo metabolism processes were tentatively identified. These metabolites indicated that loganin was mainly metabolized to the demethylated product, and morroniside was firstly deglycosylated to the aglycone and the latter was subsequently demethylated and acetylated. Additionally, hydrogenation and deglycosylation were the principal metabolic reactions of catalpol; while O-glucuronide and O-sulphate conjugates were observed as major metabolites for methylated caffeic acid and hydroxytyrosol released from acteoside. Compared with the normal group, the CKD rat showed lower conversion capability. Few kinds and minor amounts of the metabolites appeared in the CKD rat samples. While considerable amounts of the parent compounds were detected in the CKD plasma. This will help maintain a high blood drug concentration which might be beneficial for the treatment of CKD. The proposed method could develop an integrated template approach to analyze screening and identification of the bioactive components in plasma, urine and feces after oral administration of herb medicines. Additionally, this investigation might provide helpful chemical information for further pharmacology and active mechanism research on herb medicines.

Absorption, Distribution, Metabolism, and Excretion of [14C]-Volixibat in Healthy Men: Phase 1 Open-Label Study.

BACKGROUND AND OBJECTIVES: Volixibat is a potent inhibitor of the apical sodium-dependent bile acid transporter in development for the treatment of nonalcoholic steatohepatitis. This phase 1, open-label study investigated the absorption, distribution, metabolism, and excretion of [14C]-volixibat in heathy men. METHODS: Eligible men (n = 8) aged 18-50 years (body mass index 18.0-30.0 kg/m2; weight >50 kg) received a single oral dose of [14C]-volixibat 50 mg containing ~5.95 µCi radioactivity. The primary objectives were to assess the pharmacokinetics of [14C]-volixibat and to determine the total radioactivity in whole blood, plasma, urine, and feces at pre-selected time points over 6 days. The secondary objectives were to characterize metabolites and to assess the safety and tolerability. RESULTS: Low concentrations of volixibat (range 0-0.179 ng/mL) were detected in plasma up to 8 h following administration; the pharmacokinetic parameters could not be calculated. No radioactivity was observed in plasma or whole blood. The percentage (mean ± standard deviation) of total radioactivity in urine was 0.01 ± 0.007%. The vast majority (92.3 ± 5.25%) of volixibat was recovered in feces (69.2 ± 33.1% within 24 h). Unchanged volixibat was the only radioactive component detected in feces. Adverse events were mild in severity and mostly gastrointestinal. Changes in laboratory values were not clinically meaningful. CONCLUSIONS: Following oral administration, [14C]-volixibat was excreted unchanged from the parent compound almost exclusively via fecal excretion, indicating that the drug is minimally absorbed. Consistent with other studies, adverse events were primarily gastrointestinal in nature. ClinicalTrials.gov identifier NCT02571192.

Pharmacokinetics and disposition of monoterpene glycosides derived from Paeonia lactiflora roots (Chishao) after intravenous dosing of antiseptic XueBiJing injection in human subjects and rats.

AIM: Monoterpene glycosides derived from Paeonia lactiflora roots (Chishao) are believed to be pharmacologically important for the antiseptic herbal injection XueBiJing. This study was designed to characterize the pharmacokinetics and disposition of monoterpene glycosides. METHODS: Systemic exposure to Chishao monoterpene glycosides was assessed in human subjects receiving an intravenous infusion and multiple infusions of XueBiJing injection, followed by assessment of the pharmacokinetics of the major circulating compounds. Supportive rat studies were also performed. Membrane permeability and plasma-protein binding were assessed in vitro. RESULTS: A total of 18 monoterpene glycosides were detected in XueBiJing injection (content levels, 0.001-2.47 mmol/L), and paeoniflorin accounted for 85.5% of the total dose of monoterpene glycosides detected. In human subjects, unchanged paeoniflorin exhibited considerable levels of systemic exposure with elimination half-lives of 1.2-1.3 h; no significant metabolite was detected. Oxypaeoniflorin and albiflorin exhibited low exposure levels, and the remaining minor monoterpene glycosides were negligible or undetected. Glomerular-filtration-based renal excretion was the major elimination pathway of paeoniflorin, which was poorly bound to plasma protein. In rats, the systemic exposure level of paeoniflorin increased proportionally as the dose was increased. Rat lung, heart, and liver exposure levels of paeoniflorin were lower than the plasma level, with the exception of the kidney level, which was 4.3-fold greater than the plasma level; brain penetration was limited by the poor membrane permeability. CONCLUSION: Due to its significant systemic exposure and appropriate pharmacokinetic profile, as well as previously reported antiseptic properties, paeoniflorin is a promising XueBiJing constituent of therapeutic importance.

Excretion of Morroniside in Rat Urine After Single Oral and Intravenous Administration.

This study was designed to develop a sensitive, simple and rapid method for the quantitation of morroniside in rat urine using high-performance liquid chromatography-tandem mass spectrometry (LC-MS-MS) and to investigate the excretion of morroniside in rat urine. The mobile phase consisted of water-acetonitrile (gradient elution) at a flow rate of 0.4 mL/min. Detection was performed using positive-ion electrospray ionization in multiple reaction monitoring (MRM) modes. And the detection of morroniside in rat urine by the LC-MS-MS was accurate and precise from 1.0 to 2,500 ng/mL (a correlation coefficient of 0.9953). The recoveries and matrix effects were all in line with the biological sample measurement requirements. The intraday accuracy was 88.68-105.78% with precision of 6.50-11.19% and the interday accuracy was 95.77-102.43% with precision of 7.08-10.40%. Excretion data of morroniside in rat urine indicated that 21.43‰ (i.g.) and 100.35% (i.v.) of the dose administered was excreted as unconverted form, respectively. And the maximal excretion rate was 27.57 and 482.42 µg/h after oral and intravenous administration, respectively. These results indicated that the developed method has satisfactory sensitivity, accuracy and precision for the quantification of morroniside in rat urine.

The antibacterial activity of syringopicroside, its metabolites and natural analogues from Syringae Folium.

In the present study, the in vitro antibacterial activity of an effective fraction (ESF) from Syringae Folium (SF) on Methicillin-resistant Staphylococcus aureus (MRSA) was evaluated and then its in vivo activity was evaluated by using the MRSA-infected mouse peritonitis model. The ESF showed a significant in vitro and in vivo activity on decreasing the Minimum Inhibitory Concentrations (MICs) and increasing the survival rate of mouse from 42.8% to 100%. Six iridoid glucosides (IGs) of ESF were characterized by UPLC-TOF-MS method and also isolated by column chromatography. Most of them showed in vitro anti MRSA activity. Syringopicroside (Sy), the major compound of IGs, was found to increase the survival rate from 42.8% to 92.8% of the MRSA-infected mouse, which revealed Sy is also the main active components of ESF. In order to know why the effect of oral administration of SF is better than its injections in clinic and the metabolites of Sy, seven metabolites of Sy were isolated from rat urine and identified on the basis of NMR and MS spectra. Most of metabolites possessed stronger in vitro anti-MRSA activity than that of Sy, which furtherly proved the clinical result.

Identification of chemical constituents and rat metabolites of Kangxianling granule by HPLC-Q-TOF-MS/MS.

A high-performance liquid chromatography coupled with quadrupole time-of-flight mass tandem mass spectrometry method was established to characterize the chemical constituents of Kangxianling granule (KXL), a traditional Chinese medicine formula, and the metabolic profile in rat urine and plasma after oral administration of KXL. A total of 27 compounds in KXL extract and 13 prototype compounds with 12 metabolites in rat urine and plasma were identified. Among the 27 detected compounds, 15 were identified by comparing the retention time and MS data with that of reference compounds and the other 12 compounds were tentatively assigned based on the MS data and reference literature. The main prototype components absorbed in rat were amygdalin, salvianolic acid B, tanshinones and anthraquinones. Hydroxylation, glucuronidation and sulfation were the principal metabolic pathways in rat. The results revealed that the 25 compounds identified in rat urine and plasma were the potential active ingredients of KXL, which provides helpful chemical information for further study of the pharmacology mechanism of KXL.

Comparison of the urinary excretion of quercetin glycosides from red onion and aglycone from dietary supplements in healthy subjects: a randomized, single-blinded, cross-over study.

Some intervention studies have shown that quercetin supplementation can regulate certain biomarkers, but it is not clear how the doses given relate to dietary quercetin (e.g. from onion). We conducted a two-period, two-sequence crossover study to compare the bioavailability of quercetin when administered in the form of a fresh red onion meal (naturally glycosylated quercetin) or dietary supplement (aglycone quercetin) under fasting conditions. Six healthy, non-smoking, adult males with BMI 22.7 ± 4.0 kg m(-2) and age 35.3 ± 12.3 y were grouped to take the two study meals in random order. In each of the 2 study periods, one serving of onion soup (made from 100 g fresh red onion, providing 156.3 ± 3.4 µmol (47 mg) quercetin) or a single dose of a quercetin dihydrate tablet (1800 ± 150 µmol (544 mg) of quercetin) were administered following 3 d washout. Urine samples were collected up to 24 h, and after enzyme deconjugation, quercetin was quantified by LC-MS. The 24 h urinary excretion of quercetin (1.69 ± 0.79 µmol) from red onion in soup was not significantly different to that (1.17 ± 0.44 µmol) for the quercetin supplement tablet (P = 0.065, paired t-test). This means that, in practice, 166 mg of quercetin supplement would be comparable to about 10 mg of quercetin aglycone equivalents from onion. These data allow intervention studies on quercetin giving either food or supplements to be more effectively compared.

Pharmacokinetics of flavanone glycosides after ingestion of single doses of fresh-squeezed orange juice versus commercially processed orange juice in healthy humans.

Orange juice is a rich source of flavonoids considered beneficial to cardiovascular health in humans. The objective of this study was to analyze the pharmacokinetics of the main flavanone glycosides, hesperidin and narirutin, in humans after the consumption of two styles of orange juice, fresh-squeezed (FOJ) and commercially processed (POJ), differing in their amounts of soluble and insoluble forms of these compounds. Healthy human subjects consumed 11.5 mL/kg body weight of FOJ, and after an interval of 30 days, consumed the same quantity of POJ. The results showed that there were no significant differences in the Tmax of the pharmacokinetic curves for the metabolites of hesperidin and narirutin following the consumption of the two styles of juices, and corrected for differences in doses in the POJ and FOJ, there were also no significant differences in the AUC and Cmax values and percent absorption of these compounds.

Metabolism of secoisolariciresinol-diglycoside the dietary precursor to the intestinally derived lignan enterolactone in humans.

Secoisolariciresinol-diglycoside (SDG), a natural dietary lignan of flaxseeds now available in dietary supplements, is converted by intestinal bacteria to the mammalian lignans enterodiol and enterolactone. High levels of these lignans in blood and urine are associated with reduced risk of many chronic diseases. Our objective was to determine the bioavailability and pharmacokinetics of SDG in purified flaxseed extracts under dose-ranging and steady-state conditions, and to examine whether differences in secoisolariciresinol-diglycoside purity influence bioavailability. Pharmacokinetic studies were performed on healthy postmenopausal women after oral intake of 25, 50, 75, 86 and 172 mg of secoisolariciresinol-diglycoside. Extracts differing in secoisolariciresinol-diglycoside purity were compared, and steady-state lignan concentrations measured after daily intake for one week. Blood and urine samples were collected at timed intervals and secoisolariciresinol, enterodiol and enterolactone concentrations measured by mass spectrometry. Secoisolariciresinol-diglycoside was efficiently hydrolyzed and converted to secoisolariciresinol. Serum concentrations increased rapidly after oral intake, peaking after 5-7 h and disappearing with a plasma elimination half-life of 4.8 h. Maximum serum concentrations of the biologically active metabolites, enterodiol and enterolactone were attained after 12-24 h and 24-36 h, respectively, and the half-lives were 9.4 h and 13.2 h. Linear dose-responses were observed and secoisolariciresinol bioavailability correlated (r(2) = 0.835) with cumulative lignan excretion. There were no significant differences in the pharmacokinetics of extracts differing in purity, and steady-state serum lignan concentrations were obtained after one-week of daily dosing. In conclusion, this study defines the pharmacokinetics of secoisolariciresinol-diglycoside and shows it is first hydrolyzed and then metabolized in a time-dependent sequence to secoisolariciresinol, enterodiol and ultimately enterolactone, and these metabolites are efficiently absorbed.

Metabolism and excretion of kakkalide and its metabolites in rat urine, bile, and feces as determined by HPLC/UV and LC/MS/MS.

This study investigated the metabolic fate of kakkalide (irisolidone 7-xylosylglucoside), a major isoflavone found in extracts of Pueraria lobata flowers, and in rat urine, bile, and feces. Using HPLC/UV or LC/MS/MS methods, seven metabolites, tectorigenin-7-O-glucuronide, tectorigenin-7-O-sulfate, tectorigenin-4'-O-sulfate, 6-OH biochanin A-glucuronide, irisolidone-7-O-glucuronide, tectorigenin, and irisolidone were identified in rat urine after oral administration of kakkalide. Furthermore, irisolidone-7-O-glucuronide was found in bile, and irisolidone and kakkalide were found in feces. An HPLC/UV method for simultaneous quantification of all the metabolites and kakkalide in urine, bile, and feces was developed using daidzein or apigenin as the internal standard. Over a 72-h period, 13.2 ± 2.8 % of the kakkalide was excreted as seven metabolites in urine. Over the same time period, irisolidone-7-O-glucuronide excretion in bile accounted for 3.8 ± 1.1 % of the dose, while kakkalide and irisolidone excretion in feces accounted for 2.1 ± 0.7 % and 0.7 ± 0.1 % of the dose, respectively. The results indicate that urine is the primary route of kakkalide elimination in vivo and that extensive metabolism may be one of the reasons for the low bioavailability of kakkalide.

In vivo metabolism study of vaccarin in rat using HPLC-LTQ-MSn.

In order to illustrate the main biotransformation pathways of vaccarin in vivo, metabolites of vaccarin in rats were identified using a specific and sensitive high-performance liquid chromatography-electrospray ionization linear ion trap mass spectrometry (LTQ XL™) method. The rats were administered a single dose (200 mg/kg) of vaccarin by oral gavage. By comparing their changes in molecular masses (ΔM), retention times and spectral patterns with those of the parent drug, the parent compound and six metabolites were found in rat urine after oral administration of vaccarin. The parent compound and five metabolites were detected in rat plasma. In heart, liver and kidney samples, respectively, one, four and three metabolites were identified, in addition to the parent compound. Three metabolites, but no trace of parent drug, were found in the rat feces. This is the first systematic metabolism study of vaccarin in vivo. The biotransformation pathways of vaccarin involved methylation, hydroxylation, glycosylation and deglycosylation.

[Bioavailability and metabolism of flavonoids].

Published data about bioavailability and metabolism of flavonoids are reviewed. Information concerning the absorption of flavonoids in a digestive path and the participation of microorganisms in their hydrolysis is summarized. Parameters of pharmacokinetics are presented for the main classes of flavonoids, including flavanes (flavan-3-ols), anthocyans, flavones, flavonols, and flavanones.

Bioavailability of cyanidin glycosides from natural chokeberry (Aronia melanocarpa) juice with dietary-relevant dose of anthocyanins in humans.

The aim of this study was to investigate the bioavailability of anthocyanins from chokeberry juice with a dietary-relevant dose of anthocyanins. Thirteen healthy volunteers consumed chokeberry juice providing 0.8 mg of anthocyanins/kg of body weight. Before and after juice consumption, blood and urine were collected. Concentration of anthocyanins was measured with HPLC-PDA-MS-ESI. Cyanidin-3-galactoside comprised 66% of total chokeberry anthocyanins. Eight cyanidin derivatives were found in blood and urine after juice consumption. The maximum plasma anthocyanin concentration of 32.7 ± 2.9 nmol/L was reached at 1.3 ± 0.1 h after juice consumption. The anthocyanins' urine excretion rate (62.9 ± 5.0 nmol/h) was the highest within the first 2 h. In total, 0.25 ± 0.02% of the ingested anthocyanins was excreted by the renal route during 24 h, mainly as metabolites of cyanidin. According to these observations, after consumption of a dietary-relevant dose of anthocyanins as natural chokeberry juice, anthocyanins and their metabolites were present in plasma and urine of volunteers.

Flavonol glycosides of sea buckthorn (Hippophaë rhamnoides ssp. sinensis) and lingonberry (Vaccinium vitis-idaea) are bioavailable in humans and monoglucuronidated for excretion.

Glucuronidation and excretion of sea buckthorn and lingonberry flavonols were investigated in a postprandial trial by analyzing the intact forms of flavonol glycosides as well as glucuronides in plasma, urine, and feces. Four study subjects consumed sea buckthorn (study day 1) and lingonberry (study day 2) breakfasts, and blood, urine, and fecal samples were collected for 8, 24, and 48 h, respectively. Both glycosides and glucuronides of the flavonol quercetin as well as kaempferol glucuronides were detected in urine and plasma samples after the consumption of lingonberries; 14% of flavonols in urine were glycosides, and 86% were glucuronidated forms (wt %). After the consumption of sea buckthorn, 5% of flavonols excreted in urine were detected intact, and 95% as the glucuronides (wt %). Solely glucuronides of flavonols isorhamnetin and quercetin were found in plasma after the consumption of sea buckthorn berries. Only glycosides were detected in the feces after each berry trial. Flavonol glycosides and glucuronides remained in blood and urine quite long, and the peak concentrations appeared slightly later than previously described. The berries seemed to serve as a good flavonol supply, providing steady flavonol input for the body for a relatively long time.

Isolation and identification of urinary metabolites of kakkalide in rats.

Kakkalide is a major isoflavonoid from the flowers of Pueraria lobata (Willd.) Ohwi, possessing the protective effect against ethanol-induced intoxication and hepatic injury. The metabolism of kakkalide was investigated in rats. Thirteen metabolites were isolated by using solvent extraction and repeated chromatographic methods and identified by using spectroscopic methods including UV, IR, mass spectrometry, NMR, and circular dichroism experiments. Four new compounds were identified as irisolidone-7-O-glucuronide (M-1), tectorigenin-7-O-sulfate (M-2), tectorigenin-4'-O-sulfate (M-3), and biochanin A-6-O-sulfate (M-4) together with nine known compounds identified as irisolidone (M-5), tectorigenin (M-6), tectoridin (M-7), 5,7-dihydroxy-8,4'-dimethoxyisoflavone (M-8), isotectorigenin (M-9), biochanin A (M-10), genistein (M-11), daidzein (M-12), and equol (M-13). The metabolic pathway of kakkalide was proposed, which is important to understand its metabolic fate and disposition in humans.