Andrographis paniculata Formulations: Impact on Diterpene Lactone Oral Bioavailability.

Diterpene lactones have been identified as active compounds in several medicinal plants, including Andrographis paniculata (Burm. f.) Nees, which is a medicinal plant that has been used for centuries across the world. Andrographolide is the major diterpene from A. paniculata and the main bioactive constituent of this species. The effectiveness of diterpenes can be affected by factors that limit their oral bioavailability, such as their poor water solubility, slow dissolution rates, low gastrointestinal absorption, high chemical and metabolic instability, and rapid excretion. In this context, the purpose of the present review is to compile and compare literature data on the bioavailability of diterpene lactones from A. paniculata after oral administration in medicinal plant extracts or in their free forms and to highlight strategies that have been used to improve their oral bioavailability. Considering that medicinal plant extracts are commonly used as dried powder that is reconstituted in water before oral administration, novel pharmaceutical formulation strategies that are used to overcome difficulties with diterpene solubility are also compiled in this review. The use of self-microemulsifying drug delivery systems is a good strategy to enhance the dissolution and consequently the bioavailability of andrographolide after oral administration of A. paniculata extract formulations. On the other hand, herbosome technology, pH-sensitive nanoparticles, nanosuspensions, nanoemulsions, nanocrystal suspensions, nanocrystal-based solid dispersions, and solid dispersion systems are useful to formulate andrographolide in its free form and increase its oral bioavailability. The use of a suitable andrographolide delivery system is essential to achieve its therapeutic potential.

Atractylenolide I enhances responsiveness to immune checkpoint blockade therapy by activating tumor antigen presentation.

One of the primary mechanisms of tumor cell immune evasion is the loss of antigenicity, which arises due to lack of immunogenic tumor antigens as well as dysregulation of the antigen processing machinery. In a screen for small-molecule compounds from herbal medicine that potentiate T cell-mediated cytotoxicity, we identified atractylenolide I (ATT-I), which substantially promotes tumor antigen presentation of both human and mouse colorectal cancer (CRC) cells and thereby enhances the cytotoxic response of CD8+ T cells. Cellular thermal shift assay (CETSA) with multiplexed quantitative mass spectrometry identified the proteasome 26S subunit non-ATPase 4 (PSMD4), an essential component of the immunoproteasome complex, as a primary target protein of ATT-I. Binding of ATT-I with PSMD4 augments the antigen-processing activity of immunoproteasome, leading to enhanced MHC-I-mediated antigen presentation on cancer cells. In syngeneic mouse CRC models and human patient-derived CRC organoid models, ATT-I treatment promotes the cytotoxicity of CD8+ T cells and thus profoundly enhances the efficacy of immune checkpoint blockade therapy. Collectively, we show here that targeting the function of immunoproteasome with ATT-I promotes tumor antigen presentation and empowers T cell cytotoxicity, thus elevating the tumor response to immunotherapy.

Investigation on the urinary excretion kinetics of three atractylenolides from crude and processed Atractylodis rhizoma extracts in rats by UPLC-MS/MS.

Atractylodis rhizoma is a frequently-used traditional Chinese medicine in clinical practice, which have the effect of eliminating dampness and tonifying spleen. And after being processed with wheat bran, the dryness of A. rhizoma is reduced, and the function of tonifying spleen is enhanced. Atractylenolides are the major bioactive components of A. rhizoma, including atractylenolide I (AI), atractylenolide Ⅱ (AⅡ) and atractylenolide Ⅲ (AⅢ). The present study aimed to develope a new UPLC-MS/MS method for simultaneous quantification of three atractylenolides in rat urine, and applied to the excretory kinetics in Sprague-Dawley rats after oral administration of crude and processed A. rhizoma extracts. Analytes and internal standard were detected without interference in the multiple reaction monitoring (MRM) mode with positive electrospray ionization. The excretory kinetics parameters were calculated by a urine drug analysis model of drug and statistics (DAS) 3.2.8 software. The t1/2 and Ke of three atractylenolides had no significant difference between crude and processed A. rhizoma, but the recovery accumulative excretion of them in processed A. rhizoma were apparently higher than the crude ones (p<0.05, p<0.01). The results showed that only a small amount of atractylenolides excreted in urine and processing A. rhizoma with wheat bran by stir frying could promote the urinary excretion of them.

Development and application of a rapid and sensitive LC-MS/MS method for simultaneous quantification of six diterpene lactones in rats after oral administration of Rhizoma Dioscoreae Bulbiferae extract.

Diterpene lactones have been considered as the main therapeutic and hepatotoxic constituents of Rhizoma Dioscoreae Bulbiferae in recent years. In this work, a simple, rapid and accurate LC-MS/MS method was established and validated to determine six diterpene lactones in rat plasma simultaneously, including Diosbulbin B (DIOB), Diosbulbin C (DIOC), Diosbulbin D (DIOD), Diosbulbin G (DIOG), Diosbulbin J (DIOJ) and Diosbulbin L (DIOL), after oral administration of Rhizoma Dioscoreae Bulbiferae extract. The six diterpene lactones, with the inclusion of two pairs of isomer (DIOB & D, DIOC & L), and Buspirone (internal standard, IS) were successfully separated using an XDB-C18 column with the gradient elution, consisting of water with 0.1% (v/v) FA and methanol with 0.1% (v/v) FA, under a flow rate of 0.50 mL/min in 5.8 min. Precursor-product ion transitions were optimized to be m/z 362.1 → 317.1, 363.1 → 207.1, 345.0 → 299.2, 364.3 → 347.0, 396.3 → 379.3, 363.2 → 345.1 and 386.3 → 122.2 for DIOB, DIOC, DIOD, DIOG, DIOJ, DIOL and buspirone at positive ion mode with an electrospray ionization source (ESI), respectively. The linearity ranges of this present method were 0.50 to 500 µg/L for DIOB, 20.0 to 20,000 µg/L for DIOC and 2.00 to 2000 µg/L for DIOD, DIOG, DIOJ and DIOL, respectively. And the LLOQs were as low as 0.20 µg/L for DIOB, 20.0 µg/L for DIOC and 2.00 µg/L for DIOB, D, G, J and L. The accuracy of each analyte was within the range of 95.8% to 101.0% and the precision was <11.3%. No matrix effect and carry over was observed, and the recovery of the six analytes ranged from 87.3% to 109% with the RSD <11.4% within the concentrations range. The validated method was further applied to the pharmacokinetics investigation of DIOB, DIOC, DIOD, DIOG, DIOJ and DIOL successfully after oral administration of Rhizoma Dioscoreae Bulbiferae extract at 1.53 g/kg in rats.

Cellular pharmacokinetics and pharmacodynamics mechanisms of ginkgo diterpene lactone and its modulation of P-glycoprotein expression in human SH-SY5Y cells.

Ginkgo diterpene lactone (GDL) is the raw material for ginkgo diterpene lactone meglumine injection, which is used for treating cerebral ischemia. The aims of this study were to explore the cellular pharmacokinetics of GDL in whole cells and subcellular fractions, and detect cellular pharmacodynamics on the human SH-SY5Y cells induced by oxygen-glucose deprivation and reoxygenation (OGD/R). Firstly, a simple, sensitive and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for assessing the amount of ginkgolide A (GA), B (GB) and K (GK) in cellular/subcellular samples. Then, phosphatidylserine and mitochondria membrane potential were assayed to evaluate the extent of apoptosis effect. The study showed that the cellular/subcellular accumulation of GA and GB were increased in a concentration-dependent manner; the levels of GA and GB in cytosol were the highest among these subcellular organelles. Meanwhile, GDL also attenuated the OGD/R-induced increases in the percentage of apoptotic and mitochondria membrane potential. In addition, verapamil increased the rate and amount of GA and GB entering cellular/subcellular compartments through inhibition of P-glycoprotein activity, and promoted the protective effect of GDL. The present study reports the cellular pharmacokinetics profiles of GA and GB in normal and OGD/R-induced SH-SY5Y cells in vitro for the first time, which provided valuable information for clinical safety application.

Mixing Ginkgo biloba Extract with Sesame Extract and Turmeric Oil Increases Bioavailability of Ginkgolide A in Mice Brain.

Ginkgo biloba extract (GBE) is widely used as herbal medicine. Preventive effect of GBE against dementia, including Alzheimer's disease, has been reported. The bioactive compounds in GBE that impart these beneficial effects, flavonoids and terpene lactones, have poor bioavailability. Our previous study found distribution of bioactive compounds of sesame extract in mice brain after mixing it with turmeric oil. Here, we evaluate the distribution of bioactive compounds of GBE by combining it with the mixture of sesame extract and turmeric oil (MST). The content of terpene lactones in mice serum was significantly increased in a dose-dependent manner after administration of GBE. However, the contents of terpene lactones in mice brain were not significantly changed. Concentration of ginkgolide A in mice brain increased significantly when GBE was co-administrated with MST than when GBE was administered alone. These results suggest that MST may be effective in enhancing the bioavailability of ginkgolide A in GBE.

Intestinal Absorption of Isoalantolactone and Alantolactone, Two Sesquiterpene Lactones from Radix Inulae, Using Caco-2 Cells.

BACKGROUND: Isoalantolactone and alantolactone are the main sesquiterpene lactones in Radix Inulae (dried root of Inula helenium L. or I. racemosa Hook. F.), which is a frequently utilized herbal medicine. They also occur in several plants and have various pharmacologic effects. However, they have been found to have poor oral bioavailability in rats. OBJECTIVES: To understand the intestinal absorptive characteristics of isoalantolactone and alantolactone as well specific influx and efflux transporters in their absorption. METHODS: Bidirectional permeabilities of isoalantolactone and alantolactone were investigated across Caco-2 cell monolayers. Transport assays were performed using different concentrations of two lactones and specific inhibitors of ATP-binding cassette transporters and influx transporters. RESULTS: The absorption permeability of isoalantolactone and alantolactone was high at the tested concentrations (5, 20 and 80 µmol/l), and the major permeation mechanism of both lactones was found to be passive diffusion with active efflux mediated by multidrug resistance-associated proteins (MRPs) and breast cancer resistance protein (BCRP). CONCLUSION: Our results demonstrated that the absorption permeability of isoalantolactone and alantolactone was good in the Caco-2 cell model. The isoalantolactone and alantolactone absorption elucidated in this study provides useful information for further pharmacokinetics studies. Since low intestinal absorption can now be ruled out as a cause, further studies are needed to explain the low oral bioavailability of the two sesquiterpene lactones.

Wilforine, the Q-marker and PK-maker of Tripterygium glycosides tablet: Based on preparation quantitative analysis and PK-PD study.

BACKGROUND: The quality standard of Tripterygium glycosides tablet (TGT) by CFDA can not fully reflect the effectiveness and safety. While, Q-marker was proposed to solve the problem of traditional Chinese medicine. PK-marker is mainly used to reflect the material exposure and the influencing factors of Chinese medicine after administration. PURPOSE: Based on the study of quantitative analysis, cytotoxicity and pharmacokinetics, this study screened out and confirmed whether wilforine could be served as a potential Q-marker and PK-marker of TGT. METHODS: A sensitive and selective UPLC-MS/MS method was developed and applied to quantitative research of TGT preparation and pharmacokinetics study of TGT. Then, HepG2 cells assay was used to evaluate the cytotoxicity induced by alkaloids in TGT. Then, a PK-PD research was carried out in adjuvant arthritis (AA) rats and control rats after oral administration of TGT, with different dosage and timing. The pharmacokinetic characteristics were determined and calculated by DAS1.0. The pharmacodynamics of TGT was evaluated by the change of paw swelling through one-way ANOVA analysis. RESULTS: The quality of four alkaloids showed significant difference among four manufacturers, and they were abundant component in TGT from three manufacturers of all. HepG2 cells test revealed that wilforine and wilforgine could induce the cytotoxicity obviously. Pharmacodynamics index suggested that TGT had therapeutic effect on adjuvant arthritis. Thus, the four cases of death occurred in the high dose AA rat group had proven the significant toxicity caused by continuous high dose TGT administration. Furthermore, the result of pharmacokinetic study proved that Cmax, and AUC(0-tn) of wilforine have dose-dependent and time-dependent characteristics. But for wilforgine, there was no indication that there was an accumulation phenomenon in vivo and its plasma concentration showed low exposure. Therefore, it could hardly become the PK-marker of TGT. CONCLUSION: Wilforine is proposed as a biologically active and toxic component of TGT that can be served both as Q-marker and PK-marker. The quality, clinical safety, and efficacy of TGT should be evaluated by the quality of wilforine.

A High Throughput Three-step Ultra-performance Liquid Chromatography Tandem Mass Spectrometry Method to Study Metabolites of Atractylenolide-III.

Atractylodes macrocephala Koidz (AMK) is a traditional Chinese medicine widely used in the treatment of various diseases, especially spleen deficiency. As the principle active constituents of AMK, however, the metabolites of Atractylenolide-III (A-lactone-III) have not been identified in rats yet. In this study, a three-step high throughput method based on UHPLC-Q-TOF-MS-MS was developed to profile and characterize the metabolites of A-lactone-III in rat feces, urine and plasma. The initial step was a full-scan that utilized a multiple mass defect filter (MMDF) combined with dynamic background subtraction (DBS). PeakView®1.2 and Metabolitepilot™1.5 software was then used to obtain data and seek possible metabolites. Finally, MS-MS spectra of the parent drug and possible metabolites were compared by the fragment ion peaks and retention times, which enabled metabolites to be identified. As a result, 53 metabolites were characterized in rats in vivo. The metabolic pathways of A-lactone-III were identified as including methylation, oxidation, hydroxylation, dihydroxylation, hydrogenation, glycosylation, sulfonation, and glucuronide, cysteine and N-acetylcysteine conjugation.

Pharmacokinetics of costunolide and dehydrocostuslactone after oral administration of Radix aucklandiae extract in normal and gastric ulcer rats.

Costunolide and dehydrocostuslactone are the main active ingredients of Radix Aucklandiae (RA). An accurate and sensitive LC-MS/MS method was established to simultaneously determine contents of costunolide and dehydrocostuslactone in plasma. There were significant differences in pharmacokinetic parameters (AUC0-t, Cmax,1, Cmax,2, Tmax,1, Vd, and CL) of costunolide and dehydrocostuslactone between RA group and costunolide group or dehydrocostuslactone group. The relative bioavailability of costunolide or dehydrocostuslactone of RA extract was improved. As compared to normal group, the Tmax,2 values of dehydrocostuslactone of RA in gastric ulcer group were prolonged, while the Cmax,1, Cmax,2, and AUC0-t values decreased.

Human pharmacokinetics of ginkgo terpene lactones and impact of carboxylation in blood on their platelet-activating factor antagonistic activity.

Terpene lactones are a class of bioactive constituents of standardized preparations of Ginkgo biloba leaf extract, extensively used as add-on therapies in patients with ischemic cardiovascular and cerebrovascular diseases. This investigation evaluated human pharmacokinetics of ginkgo terpene lactones and impact of their carboxylation in blood. Human subjects received oral YinXing-TongZhi tablet or intravenous ShuXueNing, two standardized ginkgo preparations. Their plasma protein-binding and platelet-activating factor antagonistic activity were assessed in vitro. Their carboxylation was assessed in phosphate-buffered saline (pH 7.4) and in human plasma. After dosing YinXing-TongZhi tablet, ginkgolides A and B and bilobalide exhibited significantly higher systemic exposure levels than ginkgolides C and J; after dosing ShuXueNing, ginkgolides A, B, C, and J exhibited high exposure levels. The compounds' unbound fractions in plasma were 45-92%. Apparent oral bioavailability of ginkgolides A and B was mostly >100%, while that of ginkgolides C and J was 6-15%. Bilobalide's bioavailability was probably high but lower than that of ginkgolides A/B. Terminal half-lives of ginkgolides A, B, and C (4-7 h) after dosing ShuXueNing were shorter than their respective values (6-13 h) after dosing YinXing-TongZhi tablet. Half-life of bilobalide after dosing the tablet was around 5 h. Terpene lactones were roughly evenly distributed in various body fluids and tissues; glomerular-filtration-based renal excretion was the predominant elimination route for the ginkgolides and a major route for bilobalide. Terpene lactones circulated as trilactones and monocarboxylates. Carboxylation reduced platelet-activating factor antagonistic activity of ginkgolides A, B, and C. Ginkgolide J, bilobalide, and ginkgo flavonoids exhibited no such bioactivity. Collectively, differences in terpene lactones' exposure between the two preparations and influence of their carboxylation in blood should be considered in investigating the relative contributions of terpene lactones to ginkgo preparations' therapeutic effects. The results here will inform rational clinical use of ginkgo preparations.

A stable isotope dilution tandem mass spectrometry method of major kavalactones and its applications.

Kava is regaining its popularity with detailed characterizations warranted. We developed an ultraperformance liquid chromatography high-resolution tandem mass spectrometry (UPLC-MS/MS) method for major kavalactones (kavain, dihydrokavain, methysticin, dihydromethysticin and desmethoxyyangonin) with excellent selectivity and specificity. The method has been validated for different matrices following the Food and Drug Administration guidance of analytical procedures and methods validation. The scope of this method has been demonstrated by quantifying these kavalactones in two kava products, characterizing their tissue distribution and pharmacokinetics in mice, and detecting their presence in human urines and plasmas upon kava intake. As expected, the abundances of these kavalactones differed significantly in kava products. All of them exhibited a large volume of distribution with extensive tissue affinity and adequate mean residence time (MRT) in mice. This method also successfully quantified these kavalactones in human body fluids upon kava consumption at the recommended human dose. This UPLC-MS/MS method therefore can be used to characterize kava products and its pharmacokinetics in animals and in humans.

Structural Modification of Natural Product Ganomycin I Leading to Discovery of a α-Glucosidase and HMG-CoA Reductase Dual Inhibitor Improving Obesity and Metabolic Dysfunction in Vivo.

It is a great challenge to develop drugs for treatment of metabolic syndrome. With ganomycin I as a leading compound, 14 meroterpene derivatives were synthesized and screened for their α-glucosidase and HMG-CoA reductase inhibitory activities. As a result, a α-glucosidase and HMG-CoA reductase dual inhibitor (( R, E)-5-(4-( tert-butyl)phenyl)-3-(4,8-dimethylnona-3,7-dien-1-yl)furan-2(5 H)-one, 7d) with improved chemical stability and long-term safety was obtained. Compound 7d showed multiple and strong in vivo efficacies in reducing weight gain, lowering HbAlc level, and improving insulin resistance and lipid dysfunction in both ob/ob and diet-induced obesity (DIO) mice models. Compound 7d was also found to reduce hepatic steatosis in ob/ob model. 16S rRNA gene sequencing, SCFA, and intestinal mucosal barrier function analysis indicated that gut microbiota plays a central and causative role in mediating the multiple efficacies of 7d. Our results demonstrate that 7d is a promising drug candidate for metabolic syndrome.

The pharmacokinetics study of ginkgolide A, B and the effect of food on bioavailability after oral administration of ginkgolide extracts in beagle dogs.

Ginkgolides are the primarily active components in Ginkgo products that are popular worldwide. However, few studies have evaluated the bioavailability of ginkgolides and the effects of food on it after oral administration of ginkgolides. In this article, pharmacokinetics and absolute bioavailability of the primary components in ginkgolide extracts were evaluated in beagle dogs. For the first time, we showed that the fed dogs had significantly increased area under the concentration-time curve and peak concentration relative to the fasted dogs based on the data from both the prototype form and total lactones of ginkgolide A (GA) and ginkgolide B (GB). In terms of the free form of the prototype ginkgolides, the absolute bioavailabilities of GA and GB were 34.8 and 5.2% in the fasted dogs, respectively, which significantly increased to an average of 78.6 and 17.0%, respectively, in the fed dogs. In terms of acidified total lactones, the absolute bioavailabilities of GA and GB were 7.5 and 14.5% in the fed dogs, and the percentages declined to 4.1 and 3.7% in the fasted dogs, respectively. It was suggested that administration of ginkgolides after meals could promote the in vivo exposure and the bioavailability of GA and GB, and hence potentially enhance therapeutic outcomes.

Identification of the absorbed components and metabolites of modified Huo Luo Xiao Ling Dan in rat plasma by UHPLC-Q-TOF/MS/MS.

To reveal the material basis of Huo Luo Xiao Ling Dan (HLXLD), a sensitive and selective ultra-high performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) method was developed to identify the absorbed components and metabolites in rat plasma after oral administration of HLXLD. The plasma samples were pretreated by liquid-liquid extraction and separated on a Shim-pack XR-ODS C18 column (75 × 3.0 mm, 2.2 µm) using a gradient elution program. With the optimized conditions and single sample injection of each positive or negative ion mode, a total of 109 compounds, including 78 prototype compounds and 31 metabolites, were identified or tentatively characterized. The fragmentation patterns of representative compounds were illustrated as well. The results indicated that aromatization and hydration were the main metabolic pathways of lactones and tanshinone-related metabolites; demethylation and oxidation were the major metabolic pathways of alkaloid-related compounds; methylation and sulfation were the main metabolic pathways of phenolic acid-related metabolites. It is concluded the developed UHPLC-Q-TOF/MS method with high sensitivity and resolution is suitable for identifying and characterizing the absorbed components and metabolites of HLXLD, and the results will provide essential data for further studying the relationship between the chemical components and pharmacological activity of HLXLD.

[Effect of Saposhnikoviae Radix on pharmacokinetics and tissue distributions of active components in Tongxie Yaofang in rats].

Tongxie Yaofang (TXYF) is a famous formula that has been used for treating gastrointestinal diseases in traditional Chinese medicine(TCM). Saposhnikoviae Radix is considered as a meridian guiding drug in TXYF and could enhance the effectiveness of prescription. However, the scientific evidence for this effect is still not clear. To reveal the interactions of Saposhnikoviae Radix with other herbs, we conducted this study on the pharmacokinetic profile and tissue distribution of active ingredients of TXYF in rats. The concentrations of four components in blood and tissues were determined by UPLC-MS/MS after oral administration with TXYF. The detection was carried out by electrospray ionization mass spectrometry in the multiple reaction monitoring (MRM) mode. The positive and negative ion switching technique was performed in the same analysis. The results revealed that Saposhnikoviae Radix could enhance Cmax, AUC0-t, and AUC0-∞ of paeoniflorin and hesperidin, and increase the distribution of atractylenolide-I, paeoniflorin and hesperidin in liver, spleen, brain and small intestine. Saposhnikoviae Radix increased the ratio of brain to blood concentrations of atractylenolide-I, paeoniflorin and hesperidin. Meanwhile, it reduced the ratio of lung to blood concentrations of atractylenolide-I and paeoniflorin. Saposhnikoviae Radix, and may enhance the effectiveness of prescriptions by promoting distribution of other herbs in brain.

Pharmacokinetics of the prototype and hydrolyzed carboxylic forms of ginkgolides A, B, and K administered as a ginkgo diterpene lactones meglumine injection in beagle dogs.

Ginkgo diterpene lactones meglumine injection (GDLI) is a commercially available product used for neuroprotection. However, the pharmacokinetic properties of the prototypes and hydrolyzed carboxylic forms of the primary components in GDLI, i.e., ginkgolide A (GA), ginkgolide B (GB), and ginkgolide K (GK), have never been fully evaluated in beagle dogs. In this work, a simple, sensitive, and reliable method based on ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) was developed, and the prototypes and total amounts of GA, GB, and GK were determined in beagle dog plasma. The plasma concentrations of the hydrolyzed carboxylic forms were calculated by subtracting the prototype concentrations from the total lactone concentrations. For the first time, the pharmacokinetics of GA, GB, and GK were fully assessed in three forms, i.e., the prototypes, the hydrolyzed carboxylic forms, and the total amounts, after intravenous administration of GDLI in beagle dogs. It was shown that ginkgolides primarily existed in the hydrolyzed form in plasma, and the ratio of hydrolysates to prototype forms of GA and GB decreased gradually to a homeostatic ratio. All of the three forms of the three ginkgolides showed linear exposure of AUC to the dosages. GA, GB, and GK showed a constant half-life approximately 2.7, 3.4, and 1.2 h, respectively, which were consistent for the forms at three dose levels (0.3, 1.0, and 3.0 mg·kg-1) and after a consecutive injection of GDLI for 7 days (1.0 mg·kg-1).

Blood-Brain Barrier Permeability of Green Tea Catechin Metabolites and their Neuritogenic Activity in Human Neuroblastoma SH-SY5Y Cells.

SCOPE: To understand the mechanism by which green tea lowers the risk of dementia, focus was placed on the metabolites of epigallocatechin gallate (EGCG), the most abundant catechin in green tea. Much of orally ingested EGCG is hydrolyzed to epigallocatechin (EGC) and gallic acid. In rats, EGC is then metabolized mainly to 5-(3',5'-dihydroxyphenyl)-γ-valerolactone (EGC-M5) and its conjugated forms, which are distributed to various tissues. Therefore, we examined the permeability of these metabolites into the blood-brain barrier (BBB) and nerve cell proliferation/differentiation in vitro. METHODS AND RESULTS: The permeability of EGC-M5, glucuronide, and the sulfate of EGC-M5, pyrogallol, as well as its glucuronide into the BBB were examined using a BBB model kit. Each brain- and blood-side sample was subjected to liquid chromatography tandem-mass spectrometry analysis. BBB permeability (%, in 0.5 h) was 1.9-3.7%. In human neuroblastoma SH-SY5Y cells, neurite length was significantly prolonged by EGC-M5, and the number of neurites was increased significantly by all metabolites examined. CONCLUSION: The permeability of EGC-M5 and its conjugated forms into the BBB suggests that they reached the brain parenchyma. In addition, the ability of EGC-M5 to affect nerve cell proliferation and neuritogenesis suggests that EGC-M5 may promote neurogenesis in the brain.

Simultaneous determination of paeonilactone A and paeonilactone B in rat plasma after oral administration of albiflorin by UPLC/TOF/MS following picolinoyl derivatization.

A new highly sensitive analytical method was developed to investigate the in vivo metabolism of albiflorin, one of the most principal components in traditional Chinese medicine. After hydrolyzation with sulfatase, the main metabolites paeonilactone A and paeonilactone B of paeoniflorin in rat plasma were successfully detected for the first time by liquid chromatography mass spectrometry following picolinoyl derivatization. Borneol was used as the internal standard compound to quantify paeonilactone A and paeonilactone B in rat plasma. Paeonilactone A and paeonilactone B show different pharmacokinetic behaviors. The maximum plasma concentration of paeonilactone A reached 36.4±5.6ng/mL at about 8h after oral administration of albiflorin at a dose of 5mg/kg, while the maximum plasma concentration of paeonilactone B reached 12.4±3.4ng/mL at about 2h. The total metabolic pathway of albiflorin in rats was proposed. Albiflorin was found to be metabolized to the sulfate of paeonilactone A and paeonilactone B which may be responsible for the biological effect of albiflorin. The new analytical method may help to elucidate the clinical efficacy of traditional Chinese formula containing albiflorin.

Chitosan dosage regimen to trap fecal oil excretion after peroral lipase inhibitor administration in mice.

This study was designed to investigate the oil entrapment and systemic oil absorption-reducing activities of chitosan. High-molecular-weight chitosan formed gel aggregates with oil and bile salts in vitro. The oil/chitosan ratio and the molecular weight of chitosan were optimized for the in vivo study, and a molecular weight >100,000 was effective in reducing the oil contamination of mouse fur. The oil/chitosan weight ratio required for effective oil entrapment was less than 13 and 5 in the in vitro and in vivo experiments, respectively. Chitosan administration was most effective during meals, and high-molecular-weight chitosan could trap and facilitate the reduction of systemic absorption of oil droplets separated by orlistat. The activity of the lipase inhibitor was not altered by chitosan as evidenced by thin layer chromatography, and orlistat was not absorbed systemically by the co-administration of chitosan.