Development of a novel UPLC-MS/MS method for the simultaneously quantification of polydatin and resveratrol in plasma: Application to a pharmacokinetic study in rats.

The purpose of this study is to develop a sensitive LC-MS-MS method to simultaneously quantify polydatin and its metabolite, resveratrol, for its application in a pharmacokinetic (PK) study and to determine polydatin hydrolysis by microflora. A Shimadzu UHPLC system coupled to an AB Sciex QTrap 4000 mass spectrometer was used for the analysis. Separation was achieved using an Acquity BEH C18 column (2.1 × 50 mm) with acetonitrile and 0.1% formic acid as the mobile phases. Analysis was performed under negative ionization mode using the multiple reaction monitoring (MRM) approach. The method was linear in the range of 9.77-1250 nM for both resveratrol and polydatin with correlation coefficient values >0.99. Themethodhas been shown to be reproducible, with intra- and inter-day accuracy and precision ±10.4% of nominal values, for both analytes. The average extraction recovery rates were 81.78-98.3% for polydatin and 86.4-103.2% for resveratrol, respectively. Matrix effect was in the acceptable range (<15%). The analytes in plasma were found to be stable under bench-top, freeze-thaw, and storage (-4 °C) conditions. The metabolic studies showed that polydatin can be rapidly hydrolyzed by rat fecal S9 fractions and PK studies showed that both polydatin and resveratrol were exposed in the plasma and variable tissues. This novel UPLC-MS-MS method can quantify the levels of both polydatin and its major metabolite resveratrol in biological samples.

A high-throughput and simultaneous determination of combretastatin A-4 phosphate and its metabolites in human plasma using HPLC-MS/MS: Application to a clinical pharmacokinetic study.

To investigate the clinical pharmacokinetics of CA4P, a high-throughput high-performance liquid chromatography-tandem mass spectrometry assay with an identical positive electrospray ionization (ESI) mode was developed for the simultaneous determination of CA4P, its active metabolite CA4, and CA4 glucuronide in human plasma. CA4P and CA4 were easier to protonate in positive ESI mode, whereas CA4G was reported to produce deprotonated ion in negative ESI mode. Because the baseline separation of CA4P and CA4G could not be achieved, using MS positive/negative ion switching is not feasible. In this study, an abundant ammonium adduct ion of CA4G in ESI+ was observed as an ideal precursor ion. The final precursor/product transition pairs chosen for CA4P, CA4, and CA4G were at m/z 397/350, 317/286, and 510/317, respectively. To the best of our knowledge, it is the first report on the simultaneous quantification of CA4P, CA4, and CA4G in biological samples. The proposed method was validated, which showed a wide linear dynamic range, high selectivity and sensitivity, good repeatability, and a short run time. Compared with the literatures, the lower limits of quantification were five- and two-fold more sensitive for CA4G and CA4, respectively. Therefore, this method was successfully applied to the pharmacokinetic study of CA4P in phase I clinical trial.

Nicotinamide Riboside and Pterostilbene Cooperatively Delay Motor Neuron Failure in ALS SOD1G93A Mice.

Oxidative stress-induced damage is a major mechanism in the pathophysiology of amyotrophic lateral sclerosis (ALS). A recent human clinical trial showed that the combination of nicotinamide riboside (NR) and pterostilbene (PT), molecules with potential to interfere in that mechanism, was efficacious in ALS patients. We examined the effect of these molecules in SOD1G93A transgenic mice, a well-stablished model of ALS. Assessment of neuromotor activity and coordination was correlated with histopathology, and measurement of proinflammatory cytokines in the cerebrospinal fluid. Cell death, Nrf2- and redox-dependent enzymes and metabolites, and sirtuin activities were studied in isolated motor neurons. NR and PT increased survival and ameliorated ALS-associated loss of neuromotor functions in SOD1G93A transgenic mice. NR and PT also decreased the microgliosis and astrogliosis associated with ALS progression. Increased levels of proinflammatory cytokines were observed in the cerebrospinal fluid of mice and humans with ALS. NR and PT ameliorated TNFα-induced oxidative stress and motor neuron death in vitro. Our results support the involvement of oxidative stress, specific Nrf2-dependent antioxidant defenses, and sirtuins in the pathophysiology of ALS. NR and PT interfere with the mechanisms leading to the release of proapoptotic molecular signals by mitochondria, and also promote mitophagy.

Selective separation and purification of polydatin by molecularly imprinted polymers from the extract of Polygoni Cuspidati Rhizoma et Radix, rats' plasma and urine.

Molecularly imprinted polymers (MIPs) based on polydatin were prepared by precipitation polymerization method. Synthesis process of MIPs was optimized by discussion of functional monomers, porogens and the molar ratio of template- functional monomer-cross linker. Then, MIPs were prepared with polydatin as the template, 4-vinyl pyridine as the functional monomer, ethylene glycol dimethyl acrylate as the cross linker, acetonitrile as the porogen and the molar ratio of template-monomer-cross linker at 1:10:20. Scanning electron microscopy and Fourier transform infrared spectrometer were used to inspect macroscale and chemical bond of MIPs. Adsorption capability and selectivity of MIPs to polydatin were investigated by carrying out the static, dynamic and selective experiments. The results showed MIPs performed high adsorption ability and selectivity to polydatin, indicating MIPs could be used to separate and enrich polydatin from the complex systems. Finally, MIPs were applied as the adsorbent for isolation and purification of polydatin from the extract of Polygoni Cuspidati Rhizoma et Radix, rats' plasma and urine samples. MIPs were successfully used to separate polydatin from the Polygoni Cuspidati Rhizoma et Radix and recovery ranged from 89.2% to 91.6%. The maximum concentration of polydatin in rats' plasma and urine samples was 2.84 ± 0.0748 µg mL-1 and 2.64 ± 0.485 µg mL-1, respectively. Moreover, to compare with the MIPs method, organic solvent methods were used to analyze the polydatin in rats' plasma and urine samples. The results illustrated MIPs method was effective and selective for enrichment of polydatin from the medicinal plants and biological samples.

Comparative pharmacokinetics of oxyresveratrol alone and in combination with piperine as a bioenhancer in rats.

BACKGROUND: Oxyresveratrol is a major bioactive component derived from the heartwood of Artocarpus lacucha. This compound exerts several biological activities, including neuroprotective effects in vitro and in vivo. However, there is limited pharmacokinetic information on this compound, especially its distribution in neuronal tissue and its route of excretion. The aim of this study was to investigate the pharmacokinetic profiles of oxyresveratrol alone and in combination with piperine as a bioenhancer in rats. METHODS: Male Wistar rats were administered with oxyresveratrol 10 mg/kg, oxyresveratrol 10 mg/kg plus piperine 1 mg/kg via intravenous or oxyresveratrol 100 mg/kg, oxyresveratrol 100 mg/kg plus piperine 10 mg/kg via oral gavage. Plasma, internal organs, urine, and feces were collected. Determination of the oxyresveratrol concentration in biological samples was performed by liquid chromatography tandem mass spectrometry. RESULTS: The combination with piperine had shown a significantly higher maximum concentration in plasma approximately 1500 µg/L within 1-2 h after oral dosing, and could increase oral bioavailability of oxyresveratrol approximately 2-fold. Oxyresveratrol could widely distributed most of the internal organs with a tissue to plasma ratio of 10-100 fold within 5 min after dosing. Urinary excretion of oxyresveratrol glucuronide was the major route of excretion after administration of oxyresveratrol alone and in combination with piperine. CONCLUSION: The addition of piperine could enhance some of the pharmacokinetic properties of oxyresveratrol via both intravenous and oral administration. This pharmacokinetic information will be useful for appropriate strategies to develop oxyresveratrol as a phytopharmaceutical product.

Comprehensive metabolism study of polydatin in rat plasma and urine using ultra-high performance liquid chromatography coupled with high-resolution mass spectrometry.

Polydatin is one of the main bioactive constituents isolated from Polygonum cuspidatum Sieb. et Zucc., which possesses various pharmacological activities. In this study, we established an efficient strategy based on ultra-high performance liquid chromatography coupled with high-resolution mass spectrometry to uncover polydatin metabolites in rat urine and plasma. Firstly, multiple mass defect filters (MMDFs) combined with high-resolution extracted ion chromatograms (HREICs) was utilized to perform post-acquisition data-mining in ESI-MS1 stage. Secondly, metabolite candidates of polydatin were expounded systematically on the basis of diagnostic product ions (DPIs), chromatographic retention times, accurate mass, and neutral loss fragments (NLFs). Consequently, a total of 41 metabolites (polydatin included) were detected and identified tentatively in 12 min. These metabolites, including 40 in rat urine and 7 in rat plasma, were presumed to generate through glucuronidation, sulfation, deglucosylation, dehydrogenation, methylation, hydrogenation, hydroxylation and their composite reactions. Meanwhile, metabolite clusters, which were set in the form radially, were found in this study. In conclusion, our study expounded polydatin metabolites in rats and provided a reference for further researches on therapeutic material basis and mechanism of polydatin.

Simultaneous Determination of Aesculin, Aesculetin, Fraxetin, Fraxin and Polydatin in Beagle Dog Plasma by UPLC-ESI-MS/MS and Its Application in a Pharmacokinetic Study after Oral Administration Extracts of Ledum palustre L.

A rapid, simple and sensitive ultra-performance liquid chromatography-electrospray-ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) method was developed and validated for the simultaneous determination of aesculin, aesculetin, fraxetin, fraxin and polydatin in beagle dog plasma for the first time. Plasma samples were pretreated by protein precipitation with methanol. Chromatographic separation was performed on an Acquity UPLC HSS T3 C18 column (2.1 mm × 100 mm, 1.8 µm) with gradient elution at a flow rate of 0.4 mL/min, using a mobile phase consisting of 0.1% formic acid (A) and acetonitrile (B). The analytes and IS were detected by multiple reaction monitoring (MRM) via negative ion mode with ion transitions of m/z 339.1⁻m/z 176.8 for aesculin, m/z 176.8⁻m/z 88.9 for aesculetin, m/z 206.8⁻m/z 192.1 for fraxetin, m/z 369.1⁻m/z 206.9 for fraxin, m/z 389.1⁻m/z 227.0 for polydatin and m/z 415.2⁻m/z 295.1 for puerarin. This method was validated according to the FDA guidelines and the results met the requirements of analysis. The calibration curves of analytes were linear with correlation coefficients more than 0.9980. The intra- and inter-day precisions were less than 15% and the accuracy was within ±15%. The maximum plasma concentration (Cmax) of aesculin, aesculetin, fraxetin, fraxin and polydatin was 46.75 ± 7.46, 209.9 ± 57.65, 369.7 ± 48.87, 67.04 ± 12.09 and 47.14 ± 12.04 ng/mL, respectively. The time to reach the maximum plasma concentration (Tmax) was 1.32 ± 0.38 h for aesculin, 1.03 ± 0.27 h for aesculetin, 0.94 ± 0.23 h for fraxetin, 0.83 ± 0.18 h for fraxin and 1.15 ± 0.15 h for polydatin. The results indicated that the absorption of aesculin might be slow in beagle dog plasma. This method was successfully applied for pharmacokinetics in beagle dog plasma after oral administration of the extracts of Ledum palustre L. at a dosage of 0.27 g/kg.

Galactosylated PLGA nanoparticles for the oral delivery of resveratrol: enhanced bioavailability and in vitro anti-inflammatory activity.

BACKGROUND: Resveratrol (RES) is a natural anti-inflammatory and antioxidant compound with poor water solubility and oral bioavailability. The present study takes the advantages of nanocarriers combined with a ligand (galactose) anchoring to orally deliver RES in an attempt to improve its bioavailability and pharmacological activity. METHODS: RES-loaded galactosylated nanoparticles (RES-GNPs) were prepared by solvent diffusion technique using poly(lactic-co-glycolic acid), synthesized N-oleoyl-d-galactosamine and Tween 80. RES-GNPs were characterized by particle size, morphology, entrapment efficiency (EE) and in vitro release. Oral bioavailability and in vitro anti-inflammatory activity were investigated in rats and lipopolysaccharides-induced RAW 264.7 cells, respectively. RESULTS: The resulting RES-GNPs were 108.4 nm around in particle size with a polydispersity index of 0.217. Furthermore, RES-GNPs possessed a high EE and a slow drug release in water. After oral administration, RES-GNPs significantly enhanced the oral bioavailability of RES, up to 335.7% relative to RES suspensions. In situ single-pass intestinal perfusion and cellular uptake experiments showed that GNPs could improve the intestinal permeability and transcellular transport of RES. Moreover, the anti-inflammatory efficacy of RES-GNPs in RAW 264.7 cells model was superior to free RES and RES-GNPs. CONCLUSION: The results indicate that RES-GNPs can effectively promote the intestinal absorption of RES and strengthen its bioactivity, which may be a promising system for the treatment of inflammatory diseases.

The Oral Bioavailability of Trans-Resveratrol from a Grapevine-Shoot Extract in Healthy Humans is Significantly Increased by Micellar Solubilization.

SCOPE: Grapevine-shoot extract Vineatrol30 contains abundant resveratrol monomers and oligomers with health-promoting potential. However, the oral bioavailability of these compounds in humans is low (˂1-2%). The aim of this study was to improve the oral bioavailability of resveratrol from vineatrol by micellar solubilization. METHODS AND RESULTS: Twelve healthy volunteers (six women, six men) randomly ingested a single dose of 500 mg vineatrol (30 mg trans-resveratrol, 75 mg trans-ε-viniferin) as native powder or liquid micelles. Plasma and urine were collected at baseline and over 24 h after intake. Resveratrol and viniferin were analyzed by HPLC. The area under the plasma concentration-time curve (AUC) and mean maximum plasma trans-resveratrol concentrations were 5.0-fold and 10.6-fold higher, respectively, after micellar supplementation relative to the native powder. However, no detectable amounts of trans-ε-viniferin were found in either plasma or urine. The transepithelial permeability of trans-resveratrol and trans-ε-viniferin across differentiated Caco-2 monolayers was consistent to the absorbed fractions in vivo. CONCLUSION: The oral bioavailability of trans-resveratrol from the grapevine-shoot extract Vineatrol30 was significantly increased using a liquid micellar formulation, without any treatment-related adverse effects, making it a suitable system for improved supplementation of trans-resveratrol.

Quantification of desoxyrhapontigenin (4-methoxyresveratrol) in rat plasma by LC-MS/MS: Application to pre-clinical pharmacokinetic study.

Desoxyrhapontigenin (DRG, 4-methoxyresveratrol or trans-3,5-dihydroxy-4'-methoxystilbene) is a naturally occurring resveratrol (RES) derivative with a variety of biological activities. To facilitate its further medicinal exploration, a reliable LC-MS/MS method was developed and validated for the quantification of DRG in rat plasma using heavy isotope labelled RES as an internal standard. The ESI was operated in its negative ion mode while DRG and RES were determined by multiple reaction monitoring (MRM) using precursor-to-product ion transitions of m/z 241.1 → 180.8 and m/z 233.0 → 191.0, respectively. This LC-MS/MS method displayed excellent selectivity, sensitivity (LLOQ = 2.5 ng/ml), accuracy (both intra- and interday mean analytical recovery within 100 ±â€¯15%) and precision (both intra- and interday CV < 15%). The mean matrix factors were all within 1.000 ±â€¯0.150 with CV < 15%. The pharmacokinetic profiles of DRG were subsequently examined in Sprague-Dawley rats. Upon intravenous administration (4 or 10 mg/kg), DRG displayed very rapid clearance (Cl = 338 ±â€¯66 or 275 ±â€¯30 ml/min/kg) and short mean residence time (MRT = 12.9 ±â€¯4.7 or 10.4 ±â€¯0.5 min). After oral administration of DRG fully solubilized by 2-hydroxypropyl-ß-cyclodextrin (HP-ß-CD), the plasma profiles of DRG were highly erratic with a low absolute bioavailability (F < 9.83 ±â€¯5.31%). When DRG was given at a higher dose (50 mg/kg) in suspension form, the F was increased to 24.1 ±â€¯5.6%. The pharmacokinetic comparison among DRG, RES and some of its hydroxyl analogues stilbenes was performed. The information obtained from this study will facilitate further exploration on DRG as well as other RES derivatives.

Oral delivery system enhanced the bioavailability of stilbenes: Resveratrol and pterostilbene.

Stilbenes are a large group of compounds with the C6 C2 C6 skeleton, in which two aromatic rings are connected by an ethylene bridge. Resveratrol and its structural analog, pterostilbene, are by far the two most widely researched stilbenes in terms of their beneficial bioactivities. However, the bioefficacy of these compounds is greatly reduced when consumed orally due to their poor aqueous solubility, which leads to poor bioavailability. To overcome the limitation, strategies improving their solubility, absorption, and systemic concentration were applied when designing a suitable edible delivery system. This review will summarize the findings from the studies evaluating the oral bioavailability of stilbenes with emphasize on the resveratrol and pterostilbene. It will also include the edible delivery systems currently available and their effect on the oral bioavailability. © 2018 BioFactors, 44(1):5-15, 2018.

Metabolism and pharmacokinetics of resveratrol and pterostilbene.

Beneficial properties of resveratrol and pterostilbene, a dimethyl ether analog of resveratrol, have attracted increasing interest in recent years. Resveratrol and pterostilbene exhibit many pharmacological similarities and both of them are generally considered to be safe for human consumption. Beyond the structural and general bioactivity similarities between them, large amounts of data are now available to reveal the metabolic fate and pharmacological differences between them. Pterostilbene was found to be more metabolically stable and usually exhibited stronger pharmacological activities than that of resveratrol. As a contribution to clarify and compare aspects like metabolic stability and pharmacokinetics of resveratrol and pterostilbene, as well as explain the pharmacological similarities and differences between them, this review presents and compares recent data on the metabolism and pharmacokinetics of resveratrol and pterostilbene. © 2018 BioFactors, 44(1):16-25, 2018.

Biological effects of combined resveratrol and vitamin D3 on ovarian tissue.

BACKGROUND: Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a natural antioxidant polyphenol able to exert a wide range of biological effect on several tissues. Despite its important beneficial properties, it has a low water solubility, which limits its therapeutic applications in humans. Resveratrol also acts as a phytoestrogen that modulates estrogen receptor (ER)-mediated transcription. In addition, it has been shown that ovarian tissues benefit greatly from vitamin D3, which exerts its beneficial effects through VDR receptors. The aim was to evaluate the cooperative effects of resveratrol combined with vitamin D3 on ovarian cells and tissues and some other organs as well. Moreover, the modulation of specific intracellular pathways involving ER and VDR receptors has been studied. METHODS: The experiments were performed both in vitro and in vivo, to analyze cell viability, radical oxygen species production, signal transductions through Western Blot, and resveratrol quantification by HPLC. RESULTS: Cell viability, radical oxygen species production, and intracellular pathways have been studied on CHO-K1 cells. Also, the relative mechanism activated following oral intake in female Wistar rats as animal model was investigated, evaluating bioavailability, biodistribution and signal transduction in heart, kidney, liver and ovarian tissues. Both in in vitro and in vivo experiments, resveratrol exerts more evident effects when administered in combination with vitD in ovarian cells, showing a common biphasic cooperative effect: The role of vitamin D3 in maintaining and supporting the biological activity of resveratrol has been clearly observed. Moreover, resveratrol plus vitamin D3 blood concentrations showed a biphasic absorption rate. CONCLUSIONS: Such results could be used as a fundamental data for the development of new therapies for gynecological conditions, such as hot-flashes.

Influence of diabetes on plasma pharmacokinetics and brain bioavailability of grape polyphenols and their phase II metabolites in the Zucker diabetic fatty rat.

SCOPE: The effect of diabetes on the pharmacokinetics, bioavailability and brain distribution of grape polyphenols and select metabolites was studied in the Zucker diabetic fatty (ZDF) rat model. METHODS AND RESULTS: (ZDF) rats and their lean controls (LN) were dosed with a Standardized Grape Polyphenol (SGP) Mixture consisting of grape seed extract, Concord grape juice and resveratrol (RES) by oral gavage for 10 days. An 8-h pharmacokinetic study was performed. After 24 h, a second dose of SGP was administered and 1 h later animals were sacrificed and brain tissue was harvested. Plasma, urine, and brain tissue were analyzed for grape polyphenols. ZDF rats exhibited significantly diminished Cmax for all catechin, epicatechin, quercetin and resveratrol conjugated metabolites. Bioavailability was significantly lower in ZDF rats for methylated flavan-3-ol, RES, and quercetin metabolites. Significantly lower levels of metabolites of RES, quercetin, and flavan-3-ols were found in brains of ZDF rats. There was no significant difference between ZDF and LN in anthocyanins in plasma and no anthocyanins were detectable in brain extracts. ZDF rats showed significantly higher urinary excretion for all polyphenols. CONCLUSION: Diabetes may alter the overall bioavailability of some polyphenols in plasma and brain in part due to higher urinary clearance.

The effect of obesity and repeated exposure on pharmacokinetic response to grape polyphenols in humans.

SCOPE: Evidence suggests that dietary pattern may affect polyphenol absorption and/or metabolism. Further, obesity is associated with lower circulating nutrients, though the reason is unclear. We investigated the pharmacokinetic (PK) response of polyphenols in obese/overweight versus lean individuals before and after repeated dosing of grape polyphenols. METHODS AND RESULTS: A pilot study was conducted in which PK challenges were administered before and after 10 days of repeated dosing with polyphenols. Volunteers (6 lean, 6 overweight/obese) consumed resveratrol, grape seed extract, and grape juice (2125 mg total polyphenols) daily. On days 1 and 11, blood samples were collected for 6 h after the polyphenol dose and analyzed for deconjugated catechin, epicatechin, resveratrol, and quercetin. Area under the plasma polyphenol mass by time curves (AUCs) were greater for catechin, epicatechin, and quercetin on day 11 versus day 1 for low BMI individuals (p = 0.039) but not high BMI individuals. Further, AUCs were greater for epicatechin and resveratrol for low versus high BMI individuals (p = 0.041), with a similar trend for catechin (p = 0.065), on day 11 but not day 1. CONCLUSION: These results suggest that that obesity and repeated exposure may modify polyphenol absorption and/or metabolism in humans.

A simple LC-MS/MS method facilitated by salting-out assisted liquid-liquid extraction to simultaneously determine trans-resveratrol and its glucuronide and sulfate conjugates in rat plasma and its application to pharmacokinetic assay.

A simple LC-MS/MS method facilitated by salting-out assisted liquid-liquid extraction (SALLE) was applied to simultaneously investigate the pharmacokinetics of trans-resveratrol (Res) and its major glucuronide and sulfate conjugates in rat plasma. Acetonitrile-methanol (80:20, v/v) and ammonium acetate (10 mol L-1 ) were used as extractant and salting-out reagent to locate the target analytes in the supernatant after the aqueous and organic phase stratification, then the analytes were determined via gradient elution by LC-MS/MS in negative mode in a single run. The analytical method was validated with good selectivity, acceptable accuracy (>85%) and low variation of precision (<15%). SALLE showed better extraction efficiency of target glucuronide and sulfate conjugates (>80%). The method was successfully applied to determine Res and its four conjugated metabolites in rat after Res administration (intragastric, 50 mg kg-1 ; intravenous, 10 mg kg-1 ). The systemic exposures to Res conjugates were much higher than those to Res (AUC0-t , i.v., 7.43 µm h; p.o., 8.31 µm h); Res-3-O-ß-d-glucuronide was the major metabolite (AUC0-t , i.v., 66.1 µm h; p.o., 333.4 µm h). The bioavailability of Res was estimated to be ~22.4%. The reproducible SALLE method simplified the sample preparation, drastically improved the accuracy of the concomitant assay and gave full consideration of extraction recovery to each target analyte in bio-samples.

Simultaneous determination of ten bioactive constituents of Sanjie Zhentong Capsule in rat plasma by ultra-high-performance liquid chromatography tandem mass spectrometry and its application to a pharmacokinetic study.

Sanjie Zhentong capsule, a well-known traditional Chinese medicine prescription, are used for the treatment of endometriosis-related diseases. In this study, a simple, rapid and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the simultaneous determination of ten bioactive constituents, including peimine, peiminine, peimisine, loureirin A, loureirin B, 7,4'-dihydroxyflavone, pterostilbene, ginsenoside Rg1, ginsenoside Rb1, and notoginsenoside R1 in rat plasma after oral administration of Sanjie Zhentong capsule. The sample preparations for protein removal was accomplished using a simple methanol precipitation method. The analytes were completely separated from the endogenous compounds on an Agilent Poroshell 120 SB-C18 column (4.6mm×150mm, 2.7µm) using an isocratic elution with methanol - 0.1% formic acid aqueous (4/1, v/v) as a mobile phase. The single-run analysis time was as short as 14.0min. The inter-day and intra-day precision of the quality control samples exhibited relative standard deviations (RSD) <9.5% and the accuracy values ranged from -8.6% to 15.0%. The lower limits of quantification (LLOQ) were 10, 10, 10, 10, 10, 10, 5, 10, 10 and 20ng/mL for peimine, peiminine, peimisine, loureirin A, loureirin B, 7,4'-dihydroxyflavone, pterostilbene, ginsenoside Rg1, ginsenoside Rb1, notoginsenoside R1, respectively. The analytical method was successfully applied to a pharmacokinetic study of the multi-components after oral administration of Sanjie Zhentong Capsule in rats.

Preparation and in-vitro/in-vivo characterization of trans-resveratrol nanocrystals for oral administration.

Trans -resveratrol (t-RES) is a natural polyphenolic compound with extensive therapeutic activities; however, its clinical application is circumscribed due to its poor solubility and low bioavailability. The purpose of this study was to prepare stable t-RES nanocrystals (t-RES-NCs) with different stabilizers to improve its oral bioavailability. t-RES-NCs were fabricated by the probe sonication method and optimized by particles size, poly dispersive index and zeta potential. The pharmaceutical characterization of t-RES-NCs was further performed systematically. The in vitro cellular efficacy and in vivo pharmacokinetics of t-RES-NCs were also evaluated. The optimized NCs were successfully accomplished in a sub-micron particle size (110.28 ± 12.55 nm) with high ζ-potential (-32.96 ± 3.85 mV) value. Scanning electron microscopy (SEM) image indicated that morphology of t-RES-NCs was regular and rod like in shape. Meanwhile, the result of in vitro cellular efficacy against MDA-MB-231 cells revealed that developed t-RES-NCs were more efficacious and potent (p < 0.05) than plain t-RES. Compared to plain t-RES, t-RES-NCs exhibited significant increase (p < 0.05) in AUC0-t (3.5-folds) and C max (2.2-folds), demonstrating improved oral bioavailability of t-RES after grafting as NCs. The significant increase in oral bioavailability of developed t-RES-NCs represents an ideal vehicle for oral delivery of t-RES which ultimately reflected the clinical efficacy of t-RES.

Lack of glucuronidation products of trans-resveratrol in plasma and urine of cats.

Resveratrol has generated interest in cats due to reported health benefits. Cats have low activity of ß-glucuronidase, and we hypothesized they could not form two common resveratrol metabolites, resveratrol-3-O-glucuronide and resveratrol-4'-O-glucuronide. Resveratrol, 3 mg/cat/day, was given orally to intact male (n = 5) and female cats (n = 5) for 4 weeks. A control group (8 intact males) was used for comparison. Plasma and urine were collected weekly and analysed using high-pressure liquid chromatography coupled with tandem mass spectrometry. Resveratrol and resveratrol-3-O-sulphate, but no glucuronide metabolites, were detected in plasma and urine. Median (range 10-90th percentile) plasma resveratrol for control and treatment groups was 0.46 ng/ml (0.02-1.74 ng/ml) and 0.96 ng/ml (0.65-3.21 ng/ml). Median (range) plasma resveratrol-3-O-sulphate for control and treatment groups was 6.32 ng/ml (2.55-10.29 ng/ml) and 11.45 ng/ml (1.47-53.29 ng/ml). Plasma resveratrol differed from control in week 4, while plasma resveratrol-3-O-sulphate was different in all weeks (p < 0.05). Median (range) urine resveratrol for control and treatment groups was 0.28 ng/ml (0.05-1.59 ng/ml) and 19.98 ng/ml (8.44-87.54 ng/ml). Median (range) urine resveratrol-3-O-sulphate for control and treatment groups was 26.71 ng/ml (10.50-75.58 ng/ml) and 108.69 ng/ml (11.83-231.05 ng/ml). All time points for urine resveratrol and resveratrol-3-O-sulphate were significantly different from control (p < 0.05), except for weeks 1, 3 and 4 for resveratrol. The results support our hypothesis that cats are unlikely able to glucuronidate resveratrol, most likely due to a reduction in the activity of ß-glucuronidase.

A simple and sensitive liquid chromatography-tandem mass spectrometry method for trans-ε-viniferin quantification in mouse plasma and its application to a pharmacokinetic study in mice.

In this study, a simple and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of trans-ε-viniferin in small volumes (10µl) of mouse plasma using chlorpropamide as an internal standard was developed and validated. Plasma samples were precipitated with acetonitrile and separated using an Eclipse Plus C18 column (100×4.6mm, 1.8-µm) with a mobile phase consisting of 0.1% formic acid in acetonitrile and 0.1% formic acid in water (60:40v/v) at a flow rate of 0.5ml/min. A triple quadrupole mass spectrometer operating in positive ion mode with selected reaction-monitoring mode was used to determine trans-ε-viniferin and chlorpropamide transitions of 455.10→215.05 and 277.00→111.00, respectively. The lower limit of quantification was 5ng/ml with a linear range of 5-2500ng/ml (r≥0.9949). All validation data, including the selectivity, precision, accuracy, recovery, dilution integrity, and stability, conformed to the acceptance requirements. No matrix effects were observed. The developed method was successfully applied to pharmacokinetic studies of trans-ε-viniferin following intravenous (2.5mg/kg), intraperitoneal (2.5, 5 and 10mg/kg), and oral (40mg/kg) administration in mice. This is the first report on the pharmacokinetic properties of trans-ε-viniferin. The results provide a meaningful basis for evaluating the pre-clinical or clinical applications of trans-ε-viniferin.