Proceedings of Chemistry, Pharmacology, Pharmacokinetics and Synthesis of Biflavonoids.

Biflavonoids, composed of two monoflavonoid residues, occur naturally in angiosperms, bryophytes, ferns, and gymnosperms. More than 592 biflavonoids have been structurally elucidated, and they can be classified into two groups of C-C and C-linear fragments-C, based on whether the linker between the two residues contains an atom. As the linker can be established on two arbitrary rings from different residues, the C-C type contains various subtypes, as does the C-linear fragment-C type. Biflavonoids have a wide range of pharmacological activities, including anti-inflammatory, antioxidant, antibacterial, antiviral, antidiabetic, antitumor, and cytotoxic properties, and they can be applied in Alzheimer's disease and Parkinson's disease. This review mainly summarizes the distribution and chemistry of biflavonoids; additionally, their bioactivities, pharmacokinetics, and synthesis are discussed.

Study on mechanism of low bioavailability of black tea theaflavins by using Caco-2 cell monolayer.

This study aimed to clarify the bioavailability mechanism of theaflavins by using the Caco-2 monolayer in vitro model. Prior to the transport of theaflavin (TF), theaflavin-3-gallate (TF3G), theaflavin-3'-gallate (TF3'G), and theaflavin-3, 3'-digallate (TFDG), we found the cytotoxicity of theaflavins was in the order of TF3'G > TFDG > TF3G > TF, suggesting the galloyl moiety enhances the cytotoxicity of theaflavins. Meantime, the galloyl moiety made theaflavins unstable, with the stability in the order of TF > TFDG > TF3G/TF3'G. Four theaflavins showed poor bioavailability with the Papp values ranging from 0.44 × 10-7 to 3.64 × 10-7 cm/s in the absorptive transport. All the theaflavins showed an efflux ratio of over 1.24. And it is further confirmed that P-glycoprotein (P-gp), multidrug resistance associated proteins (MRPs) and breast cancer resistance protein (BCRP) were all shown to contribute to the efflux transport of four theaflavins, with P-gp playing the most important role, followed by MRPs and BCRP. Moreover, theaflavins increased the expression of P-gp, MRP1, MPR3, and BCRP while decreased the expression of MRP2 at the transcription and translation levels. Additionally, the gallated theaflavins were degraded into simple theaflavins and gallic acids when transported through Caco-2 monolayers. Overall, the structural instability, efflux transporters, and cell metabolism were all responsible for the low bioavailability of four theaflavins in Caco-2 monolayers.

Associations between caseinophosphopeptides and theaflavin-3,3'-digallate and their impact on cellular antioxidant activity.

Caseinophosphopeptides (CPPs) are a group of bioactive polypeptides hydrolyzed from caseins. Theaflavin-3,3'-digallate (TF-3) is a characteristic biofunctional polyphenol in black tea. In the present study, the interactions between CPPs and TF-3 were systematically investigated with fluorescence quenching, quartz crystal microbalance with dissipation monitoring (QCM-D), circular dichroism (CD), and small-angle X-ray scattering (SAXS). Both fluorescence quenching and QCM-D studies demonstrated that TF-3 interacted with CPPs primarily through hydrogen bonding. Other forces were also involved. The addition of TF-3 did not change the secondary structures and the radius of gyration of CPPs, but it induced the aggregation of CPPs. The size of the aggregates increased with the concentration of TF-3. The impact of the association between TF-3 and CPPs on the antioxidant activity of TF-3 was studied by the cellular antioxidant activity (CAA) assay, which revealed that the cellular antioxidant activity of TF-3 was enhanced after binding to CPPs.

Black Tea Theaflavin Detoxifies Metabolic Toxins in the Intestinal Tract of Mice.

SCOPE: This study is to determine the in vivo efficacy of black tea theaflavin (TF) to detoxify two metabolic toxins, ammonia and methylglyoxal (MGO), in mice METHODS AND RESULTS: Under in vitro conditions, TF is able to react with ammonia, MGO, and hydrogen peroxide to produce its aminated, MGO conjugated, and oxidized products, respectively. In TF-treated mice, the aminated TF, the MGO conjugates of TF and aminated TF, and the oxidized TF are searched using LC-MS/MS. The results provide the first in vivo evidence that the unabsorbed TF is able to trap ammonia to form the aminated TF; furthermore, both TF and the aminated TF have the capacity to trap MGO to generate the corresponding mono-MGO conjugates. Moreover, TF is oxidized to dehydrotheaflavin, which underwent further amination in the gut. By exposing TF to germ-free (GF) mice and conventionalized mice (GF mice colonized with specific-pathogen-free microbiota), the gut microbiota is demonstrated to facilitate the amination and MGO conjugation of TF. CONCLUSION: TF has the capacity to remove the endogenous metabolic toxins through oxidation, amination, and MGO conjugation in the intestinal tract, which can potentially explain why TF still generates in vivo efficacy while showing a poor systematic bioavailability.

Preparation and antitumor evaluation of hinokiflavone hybrid micelles with mitochondria targeted for lung adenocarcinoma treatment.

Hinokiflavone (HF) is a natural biflavonoid extracted from medicinal plants such as Selaginella tamariscina and Platycladus orientalis. HF plays a crucial role in the treatment of several cancers. However, its poor solubility, instability, and low bioavailability have limited its use. In this study, soluplus/d-α-tocopherol acid polyethylene glycol 1000 succinate (TPGS)/dequalinium (DQA) was applied to improve the solubilization efficiency and stability of HF. HF hybrid micelles were prepared via thin-film hydration method. The physicochemical properties of micelles, including particle size, zeta potential, encapsulation efficiency, drug loading, CMC value, and stability were investigated. The in vitro cytotoxicity assay showed that the cytotoxicity of the HF hybrid micelles was higher than that of free HF. In addition, the HF hybrid micelles improved anticancer efficacy and induced mitochondria-mediated apoptosis, which is associated with the high levels of ROS inducing decreased mitochondrial membrane potential, promoting apoptosis of tumor cells. Furthermore, in vivo tumor suppression, smaller tumor volume and increased expression of pro-apoptotic proteins were found in nude mice treated with HF hybrid micelles, suggesting that HF hybrid micelles had stronger tumor suppressive activity compared with free HF. In summary, HF hybrid micelles developed in this study enhanced antitumor effect, which may be a potential drug delivery system for the treatment of lung adenocarcinoma.

Antioxidant activity and bioaccessibility of phenolic compounds in white, red, blue, purple, yellow and orange edible flowers through a simulated intestinal barrier.

This study assessed the phenolics and their bioaccessibility through an in vitro digestion system coupled to a simulated intestinal barrier in eight edible flowers of distinct colors, namely mini rose, torenia, mini daisy, clitoria, cosmos, cravine, begonia and tagete. The antioxidant activity of the flowers before in vitro digestion, in their derived dialyzed and non-dialyzed fractions was evaluated using distinct approaches. All flowers presented in their composition phenolic acids, stilbenes, flavanol, anthocyanin, flavonol and flavanone, however distinct compounds and contents were found in each flower. The bioaccessibility varied among the phenolics and within the flower source (p < 0.05). Cosmos presented the highest (p < 0.05) content of phenolics and activity in ORAC assay before in vitro digestion and in dialyzed and non-dialyzed fraction; the observed activity was correlated (r = 0.9) to its major compounds, hesperidin and rutin, as well as to caftaric acid and procyanidin B2. Mini rose displayed the highest antioxidant activity in FRAP and DPPH assays before in vitro digestion; its dialyzed and non-dialyzed fraction showed the highest activity in FRAP, correlated to pelargonidin 3,5-diglucoside, catechin, epicatechin galate, epicagocatechin galate, procyanidin A2, quercitin 3-glucoside and trans-resveratrol (r = 0.9). In DPPH assay, mini rose showed the highest activity in the non-dialyzed fraction, while cravine showed the highest activity in the dialyzed fraction, which was mainly correlated to syringic acid (r = 1.0), pelargonidin 3,5-diglucoside and epicatechin (r = 0.9). Results show great variability in the phenolic composition and their bioaccessibility among the edible flowers studied. Our findings indicate cosmos and mini rose as sources of bioaccessible phenolics with great antioxidant activity.

Glucuronidation and its effect on the bioactivity of amentoflavone, a biflavonoid from Ginkgo biloba leaves.

OBJECTIVES: Ginkgo biloba leaves contain amentoflavone (AMF), a dietary flavonoid that possesses antioxidant and anticancer activity. Flavonoids are extensively subjected to glucuronidation. This study aimed to determine the metabolic profile of AMF and the effect of glucuronidation on AMF bioactivity. METHODS: A pharmacokinetic study was conducted to determine the plasma concentrations of AMF and its metabolites. The metabolic profile of AMF was elucidated using different species of microsomes. The antioxidant activity of AMF metabolites was determined using DPPH/ABTS radical and nitric oxide assays. The anticancer activity of AMF metabolites was evaluated in U87MG/U251 cells. KEY FINDINGS: Pharmacokinetic studies indicated that the oral bioavailability of AMF was 0.06 ± 0.04%, and the area under the curve of the glucuronidated AMF metabolites (410.938 ± 62.219 ng/ml h) was significantly higher than that of AMF (194.509 ± 16.915 ng/ml h). UGT1A1 and UGT1A3 greatly metabolized AMF. No significant difference was observed in the antioxidant activity between AMF and its metabolites. The anticancer activity of AMF metabolites significantly decreased. CONCLUSIONS: A low AMF bioavailability was due to extensive glucuronidation, which was mediated by UGT1A1 and UGT1A3. Glucuronidated AMF metabolites had the same antioxidant but had a lower anticancer activity than that of AMF.

Improved solubility, dissolution rate, and oral bioavailability of main biflavonoids from Selaginella doederleinii extract by amorphous solid dispersion.

Amentoflavone, robustaflavone, 2″,3″-dihydro-3',3‴-biapigenin, 3',3‴-binaringenin, and delicaflavone are five major hydrophobic components in the total biflavonoids extract from Selaginella doederleinii (TBESD) that display favorable anticancer properties. The purpose of this study was to develop a new oral delivery formulation to improve the solubilities, dissolution rates, and oral bioavailabilities of the main ingredients in TBESD by the solid dispersion technique. Solid dispersions of TBESD with various hydrophilic polymers were prepared, and different technologies were applied to select the suitable carrier and method. TBESD amorphous solid dispersion (TBESD-ASD) with polyvinylpyrrolidone K-30 was successfully prepared by the solvent evaporation method. The physicochemical properties of TBESD-ASD were investigated by scanning electron microscopy, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. As a result, TBESD was found to be molecularly dispersed in the amorphous carrier. The solubilities and dissolution rates of all five ingredients in the TBESD-ASD were significantly increased (nearly 100% release), compared with raw TBESD. Meanwhile, TBESD-ASD showed good preservation stability for 3 months under accelerated conditions of 40 °C and 75% relative humidity. A subsequent pharmacokinetic study in rats revealed that Cmax and AUC0-t of all five components were significantly increased by the solid dispersion preparation. An in vivo study clearly revealed that compared to raw TBESD, a significant reduction in tumor size and microvascular density occurred after oral administration of TBESD-ASD to xenograft-bearing tumor mice. Collectively, the developed TBESD-ASD with the improved solubility, dissolution rates and oral bio-availabilities of the main ingredients could be a promising chemotherapeutic agent for cancer treatment.

Application of the dynamic gastrointestinal simulator (simgi®) to assess the impact of probiotic supplementation in the metabolism of grape polyphenols.

In this paper, the Dynamic Gastrointestinal Simulator (simgi®) is used as a model to the study the metabolic activity of probiotics at the intestinal level, and in particular, to assess the impact of probiotic supplementation in the microbial metabolism of grape polyphenols. Two independent simulations using fecal samples from two healthy volunteers were carried out. Changes in microbiota composition and in metabolic activity were assessed by qPCR and 16S rRNA gene sequencing and by analyses of phenolic metabolites and ammonium ions (NH4+). The strain Lactobacillus plantarum CLC 17 was successfully implanted in the colon compartments of the simgi® after daily feeding of 2 × 1010 CFU/day for 7 days. Overall, no changes in bacterial diversity were observed after probiotic implantation. In comparison to the digestion of the grape polyphenols on their own, the inclusion of L. plantarum CLC 17 in the simgi® colon compartments led to a greater formation of phenolic metabolites such as benzoic acids, probably by the breakdown of high-molecular-weight procyanidin polymers. These results provide evidence that the probiotic strain Lactobacillus plantarum CLC 17 may improve the metabolism of dietary polyphenols when used as a food ingredient.

Experimental confounding factors affecting stability, transport and metabolism of flavanols and hydroxycinnamic acids in Caco-2 cells.

Studying bioavailability of polyphenols is essential to understand the health effects of these compounds. Human epithelial cells are commonly used in intestinal absorption and transport experiments but the changes polyphenols undergo during incubation, due to their chemical instability under the cell culture conditions, are scarcely known and might lead to inaccurate conclusions. Based on abundance of flavanols and hydroxycinnamic acids in the diet, epicatechin, epicatechin-3-gallate and procyanidin B2 as flavanols along with 5-caffeoylquinic and 3,5-dicaffeoylquinic acids as hydroxycinnamic acids were selected to comparatively evaluate their absorption and metabolism using an in vitro Caco-2 cell model. Special emphasis was paid to the structure-stability relationship of these phenolic compounds in Dulbecco's Modified Eagle's Medium (DMEM) under the cell culture conditions. The tested compounds were scarcely absorbed and minimally metabolized by the intestinal epithelium cells. The cell transport study showed prevalent efflux for flavanols opposite to absorption for hydroxycinnamates. Intestinal metabolism revealed that hydroxycinnamates were preferentially hydrolyzed and subsequently methylated, whereas hydrolysis of flavanols could not be confirmed, being mostly conjugated to sulfate, methyl- and methyl-sulfate derivatives. It is noteworthy that methyl derivatives of procyanidin-B2 were detected inside Caco-2 cells, confirming its absorption. In addition, culture medium influenced phenol isomerization to a higher extent than cells. In conclusion, hydroxycinnamates were better absorbed than flavanols although their bioavailability was limited in this intestinal cell model.

Preparation, evaluation and metabolites study in rats of novel amentoflavone-loaded TPGS/soluplus mixed nanomicelles.

Amentoflavone (AMF) is a kind of biflavonoids existing in Ginkgo biloba leaves. It has many biological activities, such as antioxidant, anti-inflammatory, anti-bacterial, antiviral, hypoglycemic, anti-tumor and inducing apoptosis. However, its solubility and bioavailability are poor and there are a few studies on it in vivo. In this study, to improve its solubility and bioavailability, the nanomicelles were prepared with TPGS and soluplus as carriers for the first time. The particle size, Zeta potential, encapsulation efficiency, drug loading, stability, cytotoxicity, cellular uptake, and metabolites in rats were studied. Cytotoxicity, cellular uptake, and metabolites in rats of AMF-loaded TPGS/soluplus mixed micelles were compared with those of AMF. As a result, AMF-loaded TPGS/soluplus mixed micelles with a particle size of 67.33 ± 2.01 nm and Zeta potential of -0.84133 ± 0.041405 mV were successfully prepared. The encapsulation efficiency and drug loading of the mixed nanomicelles were 99.18 ± 0.76% and 2.47 ± 0.01%, respectively. The physical and chemical properties of the mixed micelles were stable within 60 d, and the cytotoxicity of the mixed micelles was much greater than that of AMF monomers. Thirty-four kinds of metabolites of AMF were identified in rats. The metabolites were mainly distributed in rat feces. No metabolites were detected in bile and plasma. 14 kinds of metabolites of the mixed micelles in rats were detected, including 11 in feces, 6 in urine, and 3 in plasma, which indicated that the bioavailability of AMF has been improved. And the toxicity to cancer cells was enhanced, which laid a foundation for the development of new drugs.

Proliposomes for oral delivery of total biflavonoids extract from Selaginella doederleinii: formulation development, optimization, and in vitro-in vivo characterization.

PURPOSE: Amentoflavone, robustaflavone, 2'',3''-dihydro-3',3'''-biapigenin, 3',3'''-binaringenin and delicaflavone are five major active ingredients in the total biflavonoids extract from Selaginella doederleinii (TBESD) with favorable anticancer properties. However, the natural-derived potent antitumor agent of TBESD is undesirable due to its poor solubility. The present study was to develop and optimize a proliposomal formulation of TBESD (P-TBESD) to improve its solubility, oral bioavailability and efficacy. MATERIALS AND METHODS: P-TBESD containing a bile salt, a protective hydrophilic isomalto-oligosaccharides (IMOs) coating, were successfully prepared by thin film dispersion-sonication method. The physicochemical and pharmacokinetic properties of P-TBESD were characterized, and the antitumor effect was evaluated using the HT-29 xenograft-bearing mice models in rats. RESULTS: Compared with TBESD, the relative bioavailability of amentoflavone, robustaflavone, 2'',3''-dihydro-3',3'''-biapigenin, 3',3'''-binaringenin and delicaflavone from P-TBESD were 669%, 523%, 761%, 955% and 191%, respectively. The results of pharmacodynamics demonstrated that both TBESD and P-TBESD groups afforded antitumor effect without systemic toxicity, and the antitumor effect of P-TBESD was significantly superior to that of raw TBESD, based on the tumor growth inhibition and histopathological examination. CONCLUSION: Hence, IMOs-modified proliposomes have promising potential for TBESD solving the problem of its poor solubility and oral bioavailability, which can serve as a practical oral preparation for TBESD in the future cancer therapy.

Validation and application of a novel LC/MS/MS method for the determination of isoginkgetin in rat plasma.

Isoginkgetin is a biflavonoid compound isolated from the leaf extracts of Ginkgo biloba. In this study, an liquid chromatography-tandem mass spectrometry (LC/MS/MS) with liquid-liquid extraction was developed and validated for the analysis of isoginkgetin in rat plasma. In the process of chromatographic separation, selected reaction monitoring transitions for isoginkgetin and IS were m/z 566.8 → 134.7 and m/z 430.8 → 269.3, respectively. The validation parameters including selectivity, linearity, LLOQ, accuracy, precision, matrix effect, stability and recovery were satisfactory. The intra- and inter-batch precision (RSD) were <12.1% in plasma, while the accuracy (RE) was within ±14.3%. This method was employed in a pharmacokinetic study on rats after the intravenous administration of isoginkgetin.

Facile Fabrication of an Amentoflavone-Loaded Micelle System for Oral Delivery To Improve Bioavailability and Hypoglycemic Effects in KKAy Mice.

In order to increase the oral bioavailability and antidiabetic effect of amentoflavone with multimechanisms, an oral micelle system was developed by using a N-vinyl pyrrolidone-maleate-guerbet alcohol monoester polymer for the first time, which was designated as P(NVP-MGAM)/AF. After oral administration, P(NVP-MGAM)/AF enhanced the oral bioavailability of amentoflavone, which was approximately 3.2 times that of amentoflavone solution. The animal study using the KKAy insulin-resistant diabetes mouse model indicated that it regulates the expression and activity of downstream signaling factors and proteins by lowering blood lipids, reducing inflammatory responses and activating the peroxisome proliferator-activated receptor (PPAR) γ signaling pathway and PI3K/Akt signaling pathway. After being made into micelles, it is more effective because of its better absorbability and bioavailability. The results from this study provide a theoretical basis for the clinical application of amentoflavone for diabetes treatment. The oral micelles of P(NVP-MGAM)/AF may become one of the most potent drugs in the treatment of diabetes mellitus, which opens up a new way for the prevention and treatment of diabetes.

Bioaccessibility of phenolic compounds in native and exotic frozen pulps explored in Brazil using a digestion model coupled with a simulated intestinal barrier.

The bioaccessibility of phenolics and antioxidant activity were determined in açaí, cupuaçu, blackberry, blueberry, jabuticaba, raspberry, cajá and soursop frozen pulps (FPs) using a digestion model coupled with a simulated intestinal barrier. Cyanidin 3-glucoside (6.56%) and pelargonidin 3-glucoside (28.33%) were bioaccessible in blueberry and raspberry. Catechin had the highest bioaccessibility in blueberry (270.71%), blackberry (137.51%), and jabuticaba (99.52%), while the highest bioaccessibility of epicatechin (153.59%) and syringic acid (147.14%) was observed in blueberry. Procyanidin B1 presented the highest bioaccessibility in cajá (102.79%) and blackberry (87.62%) and contributed to the high DPPH▪ scavenging activity observed in these FPs. The bioaccessible fraction in soursop consisted of caffeic (8.18%), p-coumaric (7.36%), caftaric (7.96%) and chlorogenic (11.08%) acids, and these acids were correlated with the iron reduction capacity of this FP. Our study assessed the bioaccessible phenolics in several FPs and showed that those found in cajá and blackberry possesses the highest antioxidant activity.

A sensitive UPLC-MS/MS method for simultaneous determination of polyphenols and theaflavins in rat plasma: Application to a pharmacokinetic study of Da Hong Pao tea.

A method based on ultra-performance liquid chromatography-tandem mass spectrometry has been developed for the rapid and simultaneous determination of five catechins and four theaflavins in rat plasma using ethyl gallate as internal standard. The pharmacokinetic profiles of these compounds were compared after oral administration of five kinds of Da Hong Pao tea to rats. Biosamples processed with a mixture of ß-glucuronidase and sulfatase were extracted with ethyl acetate-isopropanol. Chromatographic separation was achieved by gradient elution using 10 mm HCOONH4 solution and methanol as the mobile phase. Analytes were detected using negative ion electrospray ionization in multiple reaction monitoring mode. The lower limits of quantification were 1.0, 0.74 and 0.5 ng/mL for theaflavins, two catechins and three catechins, respectively. The validation parameters were well within acceptable limits. The average half-lives (t1/2 ) in blood of the reference solution group was much shorter than those of tea samples. The values of AUC0-t and Cmax of the polyphenols and theaflavins exhibited linear pharmacokinetic characteristics which were related to the dose concentration.

Intestinal Absorption and Antioxidant Activity of Grape Pomace Polyphenols.

The absorption and antioxidant activity of polyphenols from grape pomace (GP) are important aspects of its valorization as a feed additive in the diet of weaned piglets. This study aimed to evaluate the presence of polyphenols from GP both in vitro in IPEC cells and in vivo in the duodenum and colon of piglets fed with diets containing or not 5% GP and also to compare and correlate the aspects of their in vitro and in vivo absorption. Total polyphenolic content (TPC) and antioxidant status (TAS, CAT, SOD and GPx enzyme activity, and lipid peroxidation-TBARS level) were assessed in duodenum and colon of piglets fed or not a diet with 5% GP. The results of UV-Vis spectroscopy demonstrated that in cellular and extracellular medium the GP polyphenols were oxidized (between λmax = 276 nm and λmax = 627.0 nm) with the formation of o-quinones and dimers. LC-MS analysis indicated a procyanidin trimer possibly C2, and a procyanidin dimer as the major polyphenols identified in GP, 12.8% of the procyanidin trimer and 23% of the procyanidin dimer respectively being also found in the compound feed. Procyanidin trimer C2 is the compound accumulated in duodenum, 73% of it being found in the colon of control piglets, and 62.5% in the colon of GP piglets. Correlations exist between the in vitro and in vivo investigations regarding the qualitative evaluation of GP polyphenols in the cells (λmax at 287.1 nm) and in the gut (λmax at 287.5 nm), as oxidated metabolic products. Beside the presence of polyphenols metabolites this study shows also the presence of the unmetabolized procyanidin trimers in duodenum and colon tissue, an important point in evaluating the benefic actions of these molecules at intestinal level. Moreover the in vivo study shows that a 5% GP in piglet’s diet increased the total antioxidant status (TAS) and decreased lipid peroxidantion (TBARS) in both duodenum and colon, and increased SOD activity in duodenum and CAT and GPx activity in colon. These parameters are modulated by the different polyphenols absorbed, mainly by the procyanidin trimers and catechin on one side and the polyphenols metabolites on the other side.

Flavan-3-ol/Procyanidin Metabolomics in Rat Urine Using HPLC-Quadrupole TOF/MS.

SCOPE: Several studies have demonstrated that flavan-3-ol/procyanidins are associated with biological functions in the prevention of various chronic diseases, including obesity and diabetes. Knowledge of their mechanisms, including bioavailability, has significantly progressed in the last decade. However, the differences of the metabolic signatures among flavan-3-ol/procyanidins remain ambiguous. METHODS AND RESULTS: The metabolites in urine over time after acute administration of three typical flavan-3-ol/procyanidins ((epi)catechin [EPC], epigallocatechin gallate [EGCG], and procyanidin dimer [PC]) in view of the chemical structure were analyzed by HPLC-quadrupole TOF/MS. Several bile acid and amino acid derivatives including tryptophan and tyrosine, as well as flavan-3-ol/procyanidin conjugates and phenolic acid degradation products generated by the gut microbiota were observed in rat urine. CONCLUSION: Multivariate statistical analyses suggest that the exogenous and endogenous metabolites of flavan-3-ol/procyanidins greatly differ, although the chemical structures of three typical flavan-3-ol/procyanidins-EPC, EGCG, and PC-are similar. Thus, metabolomic differences likely affect their biological functions and health benefits.

Validated LC-MS/MS method for the quantification of sciadopitysin in rat plasma and its application to pharmacokinetic and bioavailability studies in vivo.

A sensitive and rapid LC-MS/MS method was developed and validated for quantitation of sciadopitysin in rat plasma using amentoflavone as an internal standard. Sample processing was accomplished after deproteinization with 150 µL aliquot of acetonitrile. Chromatographic separation was achieved using an Agela C18 column with an isocratic mobile phase comprising 2 mm ammonium acetate-acetonitrile (35:65, v/v) at a flow rate of 0.4 mL/min. Detection was performed by selection reaction monitoring on a triple-quadrupole mass spectrometer following the transitions m/z 579 → 547 and 537 → 375 for sciadopitysin and internal standard, respectively, in the negative ionization mode. The calibration curve was linear from 2.90 to 1160 ng/mL for sciadopitysin. Intra- and inter-day precisions were in the ranges 4.1-11.4 and 5.7-9.1% for sciadopitysin. Sciadopitysin was stable under different stability conditions. The validated assay was applied to pharmacokinetic and bioavailability studies in rats.

Simultaneous determination of isochamaejasmin, neochamaejasmin A and aphnoretinin rat plasma by UPLC-MS/MS and its application to a pharmacokinetic study of Stellera chamaejasme L. extract.

Isochamaejasmin, neochamaejasmin A and daphnoretin derived from Stellera chamaejasme L. are important because of their reported anticancer properties. In this study, a sensitive UPLC-MS/MS method for the determination of isochamaejasmin, neochamaejasmin A and daphnoretin in rat plasma was developed. The analyte and IS were separated on an Acquity UPLC HSS T3 column (100 × 2.1 mm, 1.8 µm) using gradient elution with the mobile phase of aqueous solution (methanol-water, 1:99, v/v, containing 1 mm formic acid) and organic solution (methanol-water, 99:1, v/v, containing 1 mm formic acid) at a flow rate of 0.3 mL/min. Multiple reaction monitoring mode with negative electrospray ionization interface was carried out to detect the components. The method was validated in terms of specificity, linearity, accuracy, precision, stability, etc. Excellent linear behavior was observed over the certain concentration ranges with the correlation coefficient values >0.99. Intra- and inter-day precisions (RSD) were <6.7% and accuracy (RE) ranged from -7.0 to 12.0%. The validated method was successfully applied to investigate the pharmacokinetics of three chemical ingredients after oral administration of S. chamaejasme L. extract to rats.