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Sulfasalazine (SAS), an anti-inflammatory drug with potent cysteine/glutamate antiporter system xc-(SXC) inhibition has recently shown beneficial effects in brain-related diseases. Despite many reports related to central nervous system (CNS) effect of SAS, pharmacokinetics (PK) and metabolite identification studies in the brain for SAS were quite limited. The aim of this study was to investigate the pharmacokinetics and metabolite identification of SAS and their distributions in mouse brain. Using in vivo brain exposure studies (neuro PK), the PK parameters of SAS was calculated for plasma as well as brain following intravenous and oral administration at 10 mg/kg and 50 mg/kg in mouse, respectively. In addition, in vivo metabolite identification (MetID) studies of SAS in plasma and brain were also conducted. The concentration of SAS in brain was much lower than that in plasma and only 1.26% of SAS was detected in mouse brain when compared to the SAS concentration in plasma (brain to plasma ratio (%): 1.26). In the MetID study, sulfapyridine (SP), hydroxy-sulfapyridine (SP-OH), and N-acetyl sulfapyridine (Ac-SP) were identified in plasma, whereas only SP and Ac-SP were identified as significant metabolites in brain. As a conclusion, our results suggest that the metabolites of SAS such as SP and Ac-SP might be responsible for the pharmacological effect in brain, not the SAS itself.

5-Amino-7-(2-phenylethyl)-2-(2-furyl)-pyrazolo(4,3-e)-1,2,4-triazolo(1,5-c) pyrimidine (SCH 58261) is one of the new chemical entities that has been developed as an adenosine A2A receptor antagonist. Although SCH 58261 has been reported to be beneficial, there is little information about SCH 58261 from a drug metabolism or pharmacokinetics perspective. This study describes the metabolism and pharmacokinetic properties of SCH 58261 in order to understand its behaviors in vivo. Rats were used as the in vivo model species. First, an LC&ndash, MS/MS method was developed for the determination of SCH 58261 in rat plasma. A GastroPlus&trade, simulation, in vitro microsomal metabolic stability, and bile duct-cannulated studies were also performed to understand its pharmacokinetic profile. The parameter sensitivity analysis of GastroPlus&trade, was used to examine the factors that influence exposure when the drug is orally administered. The factors are as follows: permeability, systemic clearance, renal clearance, and liver first-pass effect. In vitro microsomal metabolic stability indicates how much the drug is metabolized. The extrapolated hepatic clearance value of SCH 58261 was 39.97 mL/min/kg, indicating that the drug is greatly affected by hepatic metabolism. In vitro microsomal metabolite identification studies revealed that metabolites produce oxidized and ketone-formed metabolites via metabolic enzymes in the liver. The bile duct-cannulated rat study, after oral administration of SCH 58261, showed that a significant amount of the drug was excreted in feces. These results imply that the drug is not absorbed well in the body after oral administration. Taken together, SCH 58261 showed quite a low bioavailability when administered orally and this was likely due to significantly limited absorption, as well as high metabolism in vivo.

Parkinson&rsquo, s disease is one of the most common neurodegenerative diseases. Adenosine regulates the response to other neurotransmitters in the brain regions related to motor function. In the several subtypes of adenosine receptors, especially, adenosine 2A receptors (A2ARs) are involved in neurodegenerative conditions. ZM241385 is one of the selective non-xanthine A2AR antagonists with high affinity in the nanomolar range. This study describes the in vitro and in vivo pharmacokinetic properties of ZM241385 in rats. A liquid chromatography-quadrupole time-of-flight mass spectrometric (LC-qToF MS) method was developed for the determination of ZM241385 in rat plasma. In vivo IV administration studies showed that ZM241385 was rapidly eliminated in rats. However, the result of in vitro metabolic stability studies showed that ZM241385 had moderate clearance, suggesting that there is an extra clearance pathway in addition to hepatic clearance. In addition, in vivo PO administration studies demonstrated that ZM241385 had low exposure in rats. The results of semi-mass balance studies and the in silico PBPK modeling studies suggested that the low bioavailability of ZM241385 after oral administration in rats was due to the metabolism and by liver, kidney, and gut.

The novel prenyl transferase-mediated, site-specific, antibody&ndash, drug conjugate LCB14-0110 is comprised of a proprietary beta-glucuronide linker and a payload (Monomethyl auristatin F, MMAF, an inhibitor for tubulin polymerization) attached to human epidermal growth factor receptor 2 (HER2)-targeting trastuzumab. A LC-MS/MS method was developed to quantify the antibody-conjugated drug (acDrug) for in vitro linker stability and preclinical pharmacokinetic studies. The method consisted of affinity capture, enzymatic cleavage of acDrug, and LC-MS/MS analysis in the positive ion mode. A quadratic regression (weighted 1/concentration2), with the equation y = ax2 + bx + c, was used to fit calibration curves over the concentration range of 19.17~958.67 ng/mL for acDrug. The qualification run met the acceptance criteria of &plusmn, 25% accuracy and precision values for quality control (QC) samples. The overall recovery was 42.61%. The dilution integrity was for a series of 5-fold dilutions with accuracy and precision values ranging within &plusmn, 25%. The stability results indicated that acDrug was stable at all stability test conditions (short-term: 1 day, long-term: 10 months, Freeze/Thaw (F/T): 3 cycles). This qualified method was successfully applied to in vitro linker stability and pharmacokinetic case studies of acDrug in rats.

Rationale The cassette-dosing technique is a technique that administers various drugs to a single animal at once and quantitated simultaneously. The purpose of this study was to evaluate the feasibility of cassette-dosing as a means of increasing throughput and decreasing animal usage for pharmacokinetic studies of biopharmaceuticals using liquid chromatography/time-of-flight mass spectrometric (LC/TOF-MS) analysis. Methods Brentuximab, trastuzumab, cetuximab and adalimumab were used as model biopharmaceuticals. The method consisted of immunoprecipitation followed by tryptic digestion for sample preparation and LC/TOF-MS analysis of specific signature peptides in the positive ion mode using electrospray ionization. The specific signature peptides used for quantification were from the complementarity-determining regions of each mAb. All rats received a single intravenous bolus injection containing either a single mAb or a mixture of four mAbs. Results The proposed method has been qualified in linearity range of 1-100 μg/mL with correlation coefficients higher than 0.990. The qualification run met the acceptance criteria of ±25% accuracy and precision values for quality control (QC) samples. This qualified LC/TOF-MS method was successfully applied to a pharmacokinetic study in the rat. The PK properties of mAbs administered as a cassette-dosage were similar to the pharmacokinetics of each antibody drug when administered as a single entity. Conclusions These findings suggest that the cassette-dosing approach could be used to evaluate the PK properties of biopharmaceuticals in the early drug discovery stage. Also, this method would be useful for other preclinical sample analysis without developing new reagents for sample preparation.

Tozadenant is one of the selective adenosine A2a receptor antagonists with a potential to be a new Parkinson&rsquo, s disease (PD) therapeutic drug. In this study, a liquid chromatography-mass spectrometry based bioanalytical method was qualified and applied for the quantitative analysis of tozadenant in rat plasma. A good calibration curve was observed in the range from 1.01 to 2200 ng/mL for tozadenant using a quadratic regression. In vitro and preclinical in vivo pharmacokinetic (PK) properties of tozadenant were studied through the developed bioanalytical methods, and human PK profiles were predicted using physiologically based pharmacokinetic (PBPK) modeling based on these values. The PBPK model was initially optimized using in vitro and in vivo PK data obtained by intravenous administration at a dose of 1 mg/kg in rats. Other in vivo PK data in rats were used to validate the PBPK model. The human PK of tozadenant after oral administration at a dose of 240 mg was simulated by using an optimized and validated PBPK model. The predicted human PK parameters and profiles were similar to the observed clinical data. As a result, optimized PBPK model could reasonably predict the PK in human.

A therapeutic rationale is proposed for the treatment of inflammatory diseases, such as psoriasis and inflammatory bowel diseases (IBD), by selective targeting of TYK2. Hit triage, following a high-throughput screen for TYK2 inhibitors, revealed pyridine 1 as a promising starting point for lead identification. Initial expansion of 3 separate regions of the molecule led to eventual identification of cyclopropyl amide 46, a potent lead analog with good kinase selectivity, physicochemical properties, and pharmacokinetic profile. Analysis of the binding modes of the series in TYK2 and JAK2 crystal structures revealed key interactions leading to good TYK2 potency and design options for future optimization of selectivity.

A liquid chromatographic–tandem mass spectrometric (LC–MS/MS) method was developed and applied for the determination of human Aβ1-40 and Aβ1-42 peptides in transgenic mouse plasma to support preclinical pharmacodynamics studies. The method consisted of micro-elution solid phase extraction for sample preparation and LC–MS/MS analysis in the negative ion mode using electrospray ionization for analysis. 15N53-Aβ1-40 and 15N55-Aβ1-42 peptides were used as internal standards. A quadratic regression (weighted 1/concentrations), with an equation y = ax 2 + bx + c, was used to fit calibration curves over the concentration range of 0.500–100 ng/mL for both Aβ1-40 and Aβ1-42 peptides. For quality control samples at 6.00, 40.0 and 80.0 ng/mL from the qualification experiment, the within-run accuracy ranged from −2.69 to 0.583 % with precision values ≤8.23 % for Aβ1-40. Within-run accuracy ranged from −4.83 to 10.1 % with precision values ≤8.87 % for Aβ1-42. Samples from a pharmacodynamics study using Tg2576 transgenic mice were analyzed by this qualified LC–MS/MS method and concentrations were compared to those generated by ELISA. The two methods were shown to be comparable for Aβ1-40 quantification of samples from the Tg2576 amyloid precursor protein transgenic mouse model, but varied slightly for Aβ1-42.

Metabolite identification study plays an important role in determining the sites of metabolic liability of new chemical entities (NCEs) in drug discovery for lead optimization. Here we compare the two predictive software, MetaSite and StarDrop, available for this purpose. They work very differently but are used to predict the site of oxidation by major human cytochrome P450 (CYP) isoforms. Neither software can predict non-CYP catalyzed metabolism nor the rates of metabolism. For the purpose of comparing the two software packages, we tested known probe substrate for these enzymes, which included 12 substrates of CYP3A4 and 18 substrates of CYP2C9 and CYP2D6 were analyzed by each software and the results were compared. It is possible that these known substrates were part of the training set but we are not aware of it. To assess the performance of each software we assigned a point system for each correct prediction. The total points assigned for each CYP isoform experimentally were compared as a percentage of the total points assigned theoretically for the first choice prediction for all substrates for each isoform. Our results show that MetaSite and StarDrop are similar in predicting the correct site of metabolism by CYP3A4 (78% vs 83%, respectively). StarDrop appears to do slightly better in predicting the correct site of metabolism by CYP2C9 and CYP2D6 metabolism (89% and 93%, respectively) compared to MetaSite (63% and 70%, respectively). The sites of metabolism (SOM) from 34 in-house NCEs incubated in human liver microsomes or human hepatocytes were also evaluated using two prediction software packages and the results showed comparable SOM predictions. What makes this comparison challenging is that the contribution of each isoform to the intrinsic clearance (Clint) is not known. Overall the software were comparable except for MetaSite performing better for CYP2D6 and that MetaSite has a liver model that is absent in StarDrop that predicted with 82% accuracy.

The CH(2)Cl(2) extract of the stem bark of Kielmeyera albopunctata was subjected to a bioassay-linked LC-MS dereplication procedure using the KB cell line to afford the new coumarins 4-(1-methylpropyl)-5,7-dihydroxy-8-(4-hydroxy-3-methylbutyryl)-6-(3-methylbut-2-enyl)chromen-2-one (1), 9-(1-methylpropyl)-4-hydroxy-5-(4-hydroxy-3-methylbutyryl)-2-(1-hydroxy-1-methylethyl)-2,3-dihydrofuro[2,3-f]chromen-7-one (2), and 5,7-dihydroxy-8-(4-hydroxy-3-methylbutyryl)-6-(3-methylbut-2-enyl)-4-phenylchromen-2-one (3). Coumarins 1 and 3 showed moderate cytotoxicity, while 2 was inactive at 20 microg/mL. Compound 1was active in vitro against the trypomastigote form of the parasite Trypanosoma cruzi, killing 80% of the parasites after 24 h contact at 4 degrees C when added at 125 microg/mL to infected murine blood.

Four known prenylated flavonoids, artonins E (1) and O (2), artobiloxanthone (3), and cycloartobiloxanthone (4), were isolated from the stem bark of Artocarpus kemando by bioassay-guided fractionation using the DNA strand-scission and the KB cytotoxicity assays as monitors. Compounds 1 and 3 exhibited strong DNA strand-scission activity, and all four compounds were found to be cytotoxic.

trans-Resveratrol, a phenolic phytoalexin occurring in grapes, wine, peanuts, and cranberries, has been reported to both have anticarcinogenic, antioxidative, phytoestrogenic, and cardioprotective activities, and to be a weak inhibitor of cytochrome P450 (CYP)3A4, which might have significance for drug-drug interactions. Since trans-resveratrol is rapidly converted in vivo to primarily trans-resveratrol-3-sulfate, a rapid, selective, and sensitive method using liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed to investigate human cytochrome P450 inhibition by trans-resveratrol-3-sulfate. Effects of trans-resveratrol and trans-resveratrol-3-sulfate on the metabolism of selective cytochrome P450 substrates (CYP1A2/ethoxyresorufin, CYP2C9/diclofenac, CYP2C19/(S)-mephenytoin, CYP2D6/bufuralol, CYP3A4/testosterone) were monitored using cDNA-expressed human recombinant isozymes. For method validation, LC/MS/MS was used to measure the inhibition of various cytochrome P450 isozymes by different concentrations (0-50 microM) of known selective inhibitors. IC(50) values of 3.2, 1.4, 8.9, 0.2, and 0.3 microM were obtained for the standard isozyme inhibitors CYP1A2/furafylline, CYP2C9/sulfaphenazole, CYP2C19/tranylcypromine, CYP2D6/quinidine, and CYP3A4/ketoconazole, respectively, which were in good agreement with literature values. trans-Resveratrol showed IC(50) values of 11.6 microM for CYP2C19 and 1.1 microM for CYP3A4, but the IC(50) values exceeded 50 microM for all the other CYP isozymes, which indicated no inhibition. No enzyme inhibition was observed for trans-resveratrol-3-sulfate. Our results indicate that trans-resveratrol is a marginal inhibitor of CYP3A4 and a weak inhibitor of CYP2C19, but its major metabolite trans-resveratrol-3-sulfate is not an inhibitor of any of the cytochrome P450 isozymes investigated.

Betulinic acid is under development as a therapeutic agent for the treatment of metastatic malignant melanoma. In support of pharmacokinetic and toxicological evaluations, a robust assay based on liquid chromatography/mass spectrometry (LC/MS) was developed for the quantitative analysis of betulinic acid. Sample preparation consisted of deproteinization of the plasma by the addition of three volumes of acetonitrile and one volume of methanol followed by centrifugation. Aliquots of the supernatant were analyzed using an isocratic reversed-phase high-performance liquid chromatography (HPLC) system coupled to a negative ion electrospray mass spectrometer. Deprotonated molecules of betulinic acid and the isomeric internal standard oleanolic acid were detected using selected ion monitoring at m/z 455. The limit of detection of betulinic acid was 0.5 pg (1.1 fM) injected on-column (50 pg/mL, 10 microL injection volume), and the limit of quantitation was 2 pg (4.4 fM, 200 pg/mL, 10 microL injection volume). Betulinic acid was stable in plasma samples at -20 degrees C for at least 3 weeks. The intra-day and inter-day coefficients of variation of the assay wereor =6.4 andor =9.0%, respectively. The utility of the assay was demonstrated by analyzing betulinic acid spiked into mouse, rat and dog plasma, by determining the extent of binding of betulinic acid to plasma proteins, and by measuring betulinic acid in mouse and rat plasma following intraperitoneal or intravenous administration in vivo. At 15 and 25 microg/mL in mouse, rat or dog plasma, betulinic acid was 99.99% bound to serum proteins, and, at 5 microg/mL, betulinic acid wasor =99.97% bound.

A pulsed ultrafiltration-mass spectrometric screening method has been developed to evaluate the metabolic stability of drugs. Pooled human liver microsomes containing cytochrome P450 enzymes were trapped by an ultrafiltration membrane in a stirred flow-through chamber, and eight beta-blocker drugs including acebutolol, alprenolol, atenolol, metoprolol, oxprenolol, pindolol, propranolol, and timolol were flow-injected through the chamber along with the cofactor NADPH. The ultrafiltrate was collected, concentrated and analyzed by using liquid chromatography-tandem mass spectrometry (LC-MS-MS) in order to quantitate the unmetabolized fraction of each drug. The metabolic stability of each beta-blocker was determined based on the difference between the corresponding LC-MS-MS peak areas of an experimental incubation and a control without NADPH. A flow-through incubation method, pulsed ultrafiltration metabolic screening minimizes the potential for product feed back inhibition of cytochrome P450 enzymes. The importance of this phenomenon was illustrated by the observation that the metabolic stability of the set of beta-blocker drugs measured using pulsed ultrafiltration more closely resembled the in vivo stability than that determined using a conventional batch incubation with microsomes or an incubation with human hepatocytes. Since a mixture of compounds was analyzed, the relative metabolic stability of each compound could be assessed by comparison to the other compounds in the incubation. This approach might be particularly useful for the ranking of a directed library of drug leads with respect to metabolic stability and then the selection of lead compounds for further drug development.

Purpose. Resveratrol, a phenolic phytoalexin occurring in grapes, wine, peanuts, and cranberries, has been reported to have anticarcinogenic, antioxidative, phytoestrogenic, and cardioprotective activities. Because little is known about the metabolism of this potentially important compound, the in vitro and in vivo metabolism of trans-resveratrol were investigated.

Characterization and prediction of the pharmacokinetics (PK) and pharmacodynamics (PD) of Antibody-Drug Conjugates (ADCs) is challenging, since it requires simultaneous quantitative understanding about the PK-PD properties of three different molecular species i.e., the monoclonal antibody, the drug, and the conjugate. Mathematical modeling and simulation provides an excellent tool to overcome these challenges, as it can simultaneously integrate the PK-PD of ADCs and their components in a quantitative manner. Additionally, the computational PK-PD models can also serve as a cornerstone for the model-based drug development and preclinical-to-clinical translation of ADCs. To provide an overview of this subject matter, this manuscript reviews the PK-PD models applicable to ADCs. Additionally, the usage of these models during different drug development stages (i.e., discovery, preclinical development, and clinical development) is also emphasized. The importance of PK-PD modeling and simulation in making rationale go/no-go decisions throughout the drug development process is also highlighted. There is an array of PK-PD models available, ranging from the systems models specifically developed for ADCs to the empirical models applicable to all chemotherapeutic agents, which one can employ for ADCs. The decision about which model to choose depends on the questions to be answered, time at hand, and resources available.

Bioassay-guided phytochemical investigation of the roots of Exostema acuminatum (Rubiaceae) using human oral epidermoid carcinoma (KB) cells as a monitor, led to the isolation of two norditerpenoids, namely, (16R)-ent-16,17-dihydroxy-19-nor-kaur-4-en-3-one (1) and (16S)-ent-16,17-dihydroxy-19-nor-kaur-4-en-3-one (2), and six previously known 4-phenylcoumarins (3–8). The structure and relative stereochemistry of the novel compound 1 were determined by X-ray crystallography. All isolates were tested against a panel of human tumor cell lines, and the 4-phenylcoumarins showed significant cytotoxicity, with 3′-hydroxy-5,7,4′-trimethoxy-4-phenylcoumarin (5) and 8-hydroxy-5,7,4′-trimethoxy-4-phenylcoumarin (6) exhibiting the most potent activity. Two of the 4-phenylcoumarins, 5,7,4′-trimethoxy-4-phenylcoumarin (3) and 6, were evaluated in an in vivo P388 murine leukemia model.

Bioactivity-directed fractionation of the CHCl(3) extract of the roots of Ekmanianthe longiflora resulted in the isolation of three new natural products, (2R,3R,4R)-3,4-dihydro-3, 4-dihydroxy-2-(3-methyl-2-butenyl)-1(2H)-naphthalenone (1), (2S,3R, 4R)-3,4-dihydro-3, 4-dihydroxy-2-(3-methyl-2-butenyl)-1(2H)-naphthalenone (2), and (2R, 3aR,9R,9aR)-9-hydroxy-2-(1-hydroxy-1-methylethyl)-2,3,3a,4,9 , 9a-hexahydro-naphtho[2,3-b]furan-4-one (3), together with the known compounds 2-(1-hydroxyethyl)naphtho[2,3-b]furan-4,9-quinone (4), 2-acetylnaphtho[2,3-b]furan-4,9-quinone (5), dehydro-iso-alpha-lapachone (6), alpha-lapachone (7), catalponol, and epi-catalponol. The structures of 1-3 were determined using a combination of NMR spectroscopic techniques, and the absolute configurations of compounds 1 and 2 were obtained using Mosher ester methodology. Compounds 4-6 showed significant cytotoxicity in a panel of human cancer cells. alpha-Lapachone (7) exhibited only marginal activity, and catalponol and epi-catalponol were inactive in this regard. When tested at 72 mg/kg/injection in an in vivo mouse P-388 leukemia system, compound 4 was inactive (110% T/C).

A rapid and sensitive high-performance liquid chromatography–electrospray mass spectrometric method has been developed for the determination of betaine in Lycium chinense fruits. Betaine was analyzed on a system consisting of a NH2 stationary phase and a mobile phase of water–acetonitrile (25:75) by isocratic elution for 40 min. Betaine was identified and quantitated by electrospray ionization mass spectrometry with selected ion monitoring of the protonated ion [Betaine+H]+ and clustered ions [nBetaines+H]+. The limit of detection for betaine by this method was ca. 0.2 ng/ml and the relative standard deviations of the assay (intra- and inter-day) were less than 8.1%.

In searching for potent cancer chemopreventive agents from synthetic or natural products, 28 randomly selected flavonoids were screened for inhibitory effects against partially purified aromatase prepared from human placenta. Over 50% of the flavonoids significantly inhibited aromatase activity, with greatest activity being demonstrated with apigenin (IC50: 0.9 microg/mL), chrysin (IC50: 1.1 microg/mL), and hesperetin (IC50: 1.0 microg/mL).

A sensitive high-performance liquid chromatographic (HPLC) method for the determination of aloesin in plasma was developed. After solid-phase extraction from plasma and derivatization of aloesin and compound AD-1, which was prepared from aloesin as a internal standard, with 9-anthroylnitrile in the presence of quinuclidine, the derivatives were separated on a Inertsil ODS-3 column using acetonitrile/methanol/water (3∶1∶6) as a mobile phase, and detected fluorimetrically at 460 nm with excitation at 360 nm. The detection limit of aloesin was 3.2 ng/ml in plasma (S/N=3).

A new intramolecular acyl transfer from aglycon to sugar moiety in C -glucopyranoside has been observed. This unusual acyl transfer reaction has been extended to the regioselective and direct acylations of 2′-hydroxyl group of free C -glucopyranoside and one step syntheses of four natural C -glycosylchromones from aloesin glucopyranoside have also been achieved by this method. © 1997 Elsevier Science Ltd.

The photoreactivity of twelve anthraquinone derivatives was examined to evaluate its usefulness as a photo-reagent for the analysis of ginsenosides using photoreduction fluorescence (PRF) detection method. Among the tested compounds, 2-tert-butylanthraquinone (TBAQ), 2-chloroanthraquinone (CAQ) and anthraquinone (AQ) showed good characteristics as photoreagents. The detection limits of ginsenoside Rg1 by PRF-HPLC method using TBAQ, CAQ or AQ as a photo-reagent were found to be ca. 35 ng, 50 ng and 50 ng, respectively.

Ginseng saponins were analysed using HPLC with evaporative light scattering detection (ELSD). A LiChrosorb NH 2 column was used to separate ginseng saponins in white and red ginseng. The complete separation of ginsenoside Rb 1 , Rb 2 , Rc, Rd, Re, Rf, Rg 1 , Rg 2 , Rg 3 and Rh 1 was achieved within 35 min with an amino-bonded column using an acetonitrile-water-2-propanol gradient system. The ELSD drift tube temperature was set at 145°C and the nitrogen flow was set at 40 mm rotameter units. The detection limits ( S / N =3) of the ginsenosides ranged from 35 to 155 ng.

A new norisoprenoid, ficustriol (1), and the known phenanthroindolizidine alkaloid O-methyltylophorinidine (2), were isolated from a CHCl3 extract of the leaves and twigs of Ficus hispida. O-Methyltylophorinidine showed potent cytotoxic activity when tested against a small panel of human cancer cells, while ficustriol was inactive. The structure and stereochemistry of 1 were determined using chemical and spectral methods.

Bioassay-guided investigation of the twigs of Ochanostachys amentacea using LNCaP (hormone-dependent human prostate cancer) cells as a monitor led to the isolation of three alkynes, the known (S)-17-hydroxy-9,11,13,15-octadecatetraynoic acid (minquartynoic acid, 1) and two novel analogues, (S)-17,18-dihydroxy-9,11,13,15-octadecatetraynoic acid (2) and (S)-17-hydroxy-15E-octadecen-9,11,13-triynoic acid (3). Compounds 1-3 were tested against a panel of human tumor cell lines and found to be significantly cytotoxic.

A high performance liquid chromatographic method was developed for the separation and determination of seven alkaloids in “sanjoin” (the seeds ofZizyphus jujuba, Rhamnaceae), a plant with potent sedative activity. A reverse phase system of Lichrosorb RP-Select B column and 0.05 M potassium phosphate buffer (pH=3.5)-acetonitrile with gradient elution was employed. Two known alkaloids, juzirine and lysicamine, were newly isolated fom “sanjoin”.

A C-glycosyl chromone, named as 7-O-methylaloesinol, was newly isolated from the leaf exudate ofAloe capensis and identified as 8-C-beta-D-glucopyranosyl beta-2-[2-(R)-hydroxypropyl]-7-methoxy-5-methyl-4H-1-benzopyran-4-one by chemical and spectral evidence.

The first C-glucofuranosyl compound, named as neoaloesin A, was isolated from the leaves of Aloe barbadensis. Its structure was determined to be 8-alpha-D-glucofuranosyl-7-hydroxy-5-methyl-2-(2-oxopropyl)-4 H-1-benzopyran-4-one on the basis of chemical and spectral evidence.

The Caco-2 cell monolayer permeability assay has become a standard model of human intestinal absorption and transport. This paper reviews recent progress in increasing the throughput of Caco-2 cell monolayer assays and in expanding the scope of this assay to include modeling intestinal drug metabolism. The state-of-the-art in Caco-2 cell monolayer permeability assays combines multi-well plates fitted with semi-permeable inserts on which Caco-2 cells have been cultured with liquid chromatography-mass spectrometry (LC-MS) or LC-tandem mass spectrometry (LC-MS-MS) for the quantitative analysis of test compounds and the identification of their intestinal metabolites. After reviewing the progress in increasing the throughput of Caco-2 cell monolayer assays for both modeling human intestinal permeability or transport and the metabolism of xenobiotic compounds, we demonstrate the application of LC-MS and LC-MS-MS to the measurement of resveratrol permeability and metabolism in the Caco-2 model. trans-Resveratrol (trans-3,5,4'-trihydroxystilbene) is a polyphenolic compound occurring in grapes, peanuts and other food sources, that is under investigation as a cancer chemoprevention agent. The apparent permeability coefficient for apical (AP) to basolateral (BL) movement of resveratrol was 2.0 x 10(-5)cm/sec. Resveratrol was not a substrate for P-glycoprotein or the multi-drug resistance associated proteins (MRP). No phase I metabolites were observed, but the phase II conjugates resveratrol-3-glucuronide and resveratrol-3-sulfate was identified based on LC-MS and LC-MS-MS analysis and comparison with synthetic standards. Although these data indicate that resveratrol diffuses rapidly across the intestinal epithelium, extensive phase II metabolism during absorption might reduce resveratrol bioavailability.

Two compounds were newly isolated from the leaves ofAloe barbadensis Mill. Their structures were identified as 3,4-dihydro-3,9-dihydroxy-8-methoxy-3-methyl-1(2H)-anthracenone(1) and 10-beta-D-glucopyranosyl-1,8,10-trihydroxy-3-(hydroxymethyl)-(R)-9(10)-anthracenone(2) by chemical and spectral evidences.