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Thirteen previously undescribed chromene meroterpenoids, capitachromenic acids A-M (3-6, 7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b, and 11b), were identified from an ethyl acetate extract of Rhododendron capitatum, using dual high-resolution α-glucosidase and PTP1B inhibition profiling in combination with HPLC-PDA-HRMS-SPE-NMR. In addition, one known chromene meroterpenoid, daurichromenic acid (15), and its biosynthetic precursor, grifolic acid (12), two C-methylated flavanones, (2S)-5,7,4'-trihydroxy-8-methylflavanone (1) and farrerol (2), and two triterpenoids, oleanolic acid (14a) and ursolic acid (14b), were identified. New structures were elucidated by extensive 1D and 2D NMR analysis, and absolute configurations of new chromene meroterpenoids were assigned by analysis of their ECD spectra on the basis of the empirical chromane helicity rule and from Rh2(OCOCF3)4-induced ECD spectra by applying the bulkiness rule. Compounds 5, 9a, 9b, 12, and 15 showed α-glucosidase inhibitory activity with IC50 values ranging from 8.0 to 93.5 μM, while compounds 3, 5, 8b, 9a, 9b, 10b, 11b, 12, and 15 showed PTP1B inhibitory activity with IC50 values ranging from 2.5 to 68.1 μM.

Multidrug resistance (MDR) is a major challenge in cancer treatment, and the breast cancer resistance protein (BCRP) is an important target in the search for new MDR-reversing drugs. With the aim of discovering new potential BCRP inhibitors, the crude extract of leaves of Eremophila galeata, a plant endemic to Australia, was investigated for inhibitory activity of parental (HT29par) as well as BCRP-overexpressing HT29 colon cancer cells resistant to the chemotherapeutic SN-38 (i.e., HT29SN38 cells). This identified a fraction, eluted with 40% acetonitrile on a solid-phase extraction column, which showed weak growth-inhibitory activity on HT29SN38 cells when administered alone, but exhibited concentration-dependent growth inhibition when administered in combination with SN-38. The major constituent in this fraction was isolated and found to be 5,3′,5′-trihydroxy-3,6,7,4′-tetramethoxyflavone (2), which at a concentration of 25 μg/mL potentiated the growth-inhibitory activity of SN-38 to a degree comparable to that of the known BCRP inhibitor Ko143 at 1 μM. A dye accumulation experiment suggested that 2 inhibits BCRP, and docking studies showed that 2 binds to the same BCRP site as SN-38. These results indicate that 2 acts synergistically with SN-38, with 2 being a BCRP efflux pump inhibitor while SN-38 inhibits topoisomerase-1.

Background Naloxone, an opioid receptor antagonist, is used as a pharmacological tool to detect tonic endogenous activation of opioid receptors in experimental pain models. We describe a pharmacokinetic model linking naloxone pharmacokinetics to its main metabolite after high-dose naloxone infusion. Methods Eight healthy volunteers received a three-stage stepwise high-dose i.v. naloxone infusion (total dose 3.25 mg kg−1). Naloxone and naloxone-3-glucuronide (N3G) plasma concentrations were sampled from infusion onset to 334 min after infusion discontinuation. Pharmacokinetic analysis was performed using non-linear mixed effect models (NONMEM). The predictive performances of Dowling's and Yassen's models were evaluated, and target-controlled infusion simulations were performed. Results Three- and two-compartment disposition models with linear elimination kinetics described the naloxone and N3G concentration time-courses, respectively. Two covariate models were developed: simple (weight proportional) and complex (with the shallow peripheral volume of distribution linearly increasing with body weight). The median prediction error (MDPE) and wobble for Dowling's model were –32.5% and 33.4%, respectively. For Yassen's model, the MDPE and wobble were 1.2% and 19.9%, respectively. Conclusions A parent–metabolite pharmacokinetic model was developed for naloxone and N3G after high-dose naloxone infusion. No saturable pharmacokinetics were observed. Whereas Dowling's model was inaccurate and over-predicted naloxone concentrations, Yassen's model accurately predicted naloxone pharmacokinetics. The newly developed covariate models may be used for high-dose TCI-naloxone for experimental and clinical practice. Clinical trials registration NCT01992146.

Type 2 diabetes is a chronic multifactorial disease affecting more than 425 million people worldwide, and new selective α-glucosidase inhibitors with fewer side effects are urgently needed. In this study, a crude ethyl acetate extract of Machilus litseifolia was fractionated by solid-phase extraction using C18 cartridges to give a fraction enriched in α-glucosidase inhibitors. Subsequent microfractionation and bioassaying of the eluate by high-performance liquid chromatography (HPLC) using a complementary pentafluorophenyl column allowed construction of a high-resolution α-glucosidase inhibition profile (biochromatogram). This was used to target high-performance liquid chromatography-photodiode array detection-high-resolution mass spectrometry-solid-phase extraction-nuclear magnetic resonance spectroscopy (HPLC-PDA-HRMS-SPE-NMR) analysis toward α-glucosidase inhibitors. This led to the identification of 13 dicoumaroylated flavonol rhamnosides, of which seven (8, 10, 12a, 12b, 16, 17, and 18) are reported for the first time, and two lignans, of which one (5) is reported for the first time. IC50 values of isolated compounds toward α-glucosidase range from 5.9 to 35.3 μM, which is 8 to 91 times lower than the IC50 value of 266 μM measured for the reference compound acarbose.

The physiological changes following Roux-en-Y gastric bypass (RYGB) surgery may impact drug release from mechanistically different controlled-release tablets, making generic substitution inappropriate. This study aimed to characterise the pharmacokinetic-pharmacodynamic relationships of oxycodone from a lipid-based and water-swellable controlled-release tablet in RYGB patients. Twenty RYGB patients received 10-mg oral solution oxycodone or 20-mg controlled-release (water-swellable or lipid-based) oxycodone in a three-way, randomised, semiblinded and cross-over study. Blood sampling and pupillary recordings were conducted over a 24-h period. A previously established pharmacokinetic-pharmacodynamic model of these three formulations in healthy volunteers was used in the analysis as a reference model. No differences in absorption kinetics were seen between controlled-release formulations in patients. However, the absorption lag time was 11.5 min in patients vs 14 min in healthy volunteers for controlled-release tablets (P

Oral controlled-release formulations are playing an ever-increasing role in opioid therapy; however, little is known about their influence on the relationship between pharmacokinetics and pharmacodynamics. The study aim was to characterize the pharmacokinetic-pharmacodynamics of two controlled-release tablet formulations and a liquid formulation of oxycodone in healthy, opioid-naïve volunteers, which can serve as a reference for future patient studies. A semi-double-blinded, three-way crossover study was conducted, with fifteen healthy volunteers receiving two differently designed 20 mg monophasic controlled-release oxycodone tablets and 10 mg oral solution oxycodone in a randomized order. Venous plasma concentrations and pupil diameter were determined pre-dose and 0.25, 0.5, 0.75, 1, 1.5, 2, 2.33, 2.66, 3, 3.33, 3.66, 4, 5, 6, 8, 12 and 24 hour post-dose. Oxycodone pharmacokinetics was best described by a two-compartment model with first-order absorption. The controlled-release formulations had an absorption lag of 0.23 hour and a slower absorption rate constant (k aCR = 0.19 hour -1 ) compared to the oral solution (k aSOL = 0.94 hour -1 ). Effects on pupil diameter were delayed relative to plasma (14 minutes half-life) for all formulations and were best described by a proportional E max model. The plasma concentration of oxycodone at half-maximum effect was lower in males (31.1 μg/L) compared to females (52.8 μg/L; P < .001). The absorption profile of controlled-release oxycodone formulations provided a prolonged onset and offset of action compared to oral solution oxycodone. The controlled-release formulations showed no differences in pharmacokinetic and pharmacodynamic parameters suggesting that both may be used interchangeably in human beings with normal gastrointestinal function.

The correct application of bio(iso)steric replacement, a potent tool for the design of optimized compounds, requires the continuous development of new isosters able to respond to specific target requirements. Among carboxylic acid isosters, as the hydroxylated pentatomic heterocyclic systems, the hydroxy-1,2,3-triazole represents one of the most versatile but less investigated. With the purpose to enlarge its bioisosteric application, we report the results of a study devoted to obtain potential biomimetics of the γ-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system (CNS). A series of N1- and N2- functionalized 4-hydroxy-1,2,3-triazole analogues of the previous reported GABAAR ligands, including muscimol, 4-PIOL, and 4-PHP has been synthesized and characterized pharmacologically. Furthermore, this study led to development of straightforward chemical strategies directed to decorate the hydroxytriazole core scaffold, opening for further elaborative studies based on this system. The unsubstituted N1- and N2-piperidin-4-yl-4-hydroxy-1,2,3-triazole analogues (3a, 4a) of 4-PIOL and 4-PHP showed weak affinity (high to medium micromolar range), whereas substituting the 5-position of the triazole core with a 2-naphthylmethyl or 3,3-diphenylpropyl led to binding affinities in the low micromolar range. Based on electrostatic analysis and docking studies using a α1β2γ2 GABAAR homology model we were able to rationalize the observed divergence in SAR for the series of N1- and N2- piperidin-4-yl-4-hydroxy-1,2,3-triazole analogues, offering more detailed insight into the orthosteric GABAAR binding site.

A hyphenated procedure involving high-performance liquid chromatography, photodiode array detection, high-resolution mass spectrometry, solid-phase extraction, and nuclear magnetic resonance spectroscopy, i.e., HPLC-PDA-HRMS-SPE-NMR, has proven an effective technique for the identification of compounds in complex matrices. Most HPLC-PDA-HRMS-SPE-NMR investigations reported so far have relied on analytical-scale reversed-phase C18 columns for separation. Herein is reported the use of an analytical-scale pentafluorophenyl column as an orthogonal separation method following fractionation of a crude ethyl acetate extract of leaves of Coleonema album on a preparative-scale C18 column. This setup allowed the HPLC-PDA-HRMS-SPE-NMR analysis of 23 coumarins, including six new compounds, 8-O-β-d-glucopyranosyloxy-6-(2,3-dihydroxy-3-methylbut-1-yl)-7-methoxycoumarin (4), (Z)-6-(4-β-d-glucopyranosyloxy-3-methylbut-2-en-1-yl)-7-hydroxycoumarin (6), 6-(4-β-d-glucopyranosyloxy-3-methylbut-1-yl)-7-hydroxycoumarin (8), (Z...

Aim: High-dose administration of the μ-opioid receptor inverse agonist naloxone (NX), has previously been demonstrated to reinstate nocifensive behavior in the late phase of inflammatory injuries. However, no current analytical methods can provide pharmacokinetic insight into the pharmacodynamic response of high-dose administration of NX. Materials & methods: Based on protein precipitation using 50 μl human plasma, NX and naloxone-β-d-glucuronide (NXG) was analysed by UHPLC–MS/MS with 6 min cycle time. Results: A method for quantification of high-dose administered NX and NXG was developed and validated with intra- and interday precision and accuracy within ≤8.5% relative standard deviation (RSD) and -1.2–5.5% relative error (RE) for NX and ≤9.6% RSD and 0.6–6.5% RE for NXG. The method show excellent internal standard corrected matrix effects. Conclusion: A rapid UHPLC–MS/MS method was developed for quantification of NX and NXG in human plasma within 10–4000 ng/ml.

Type 2 diabetes (T2D) constituted 90% of the global 387 million diabetes cases in 2014. The enzyme protein-tyrosine phosphatase 1B (PTP1B) has been recognized as a therapeutic target for treatment of T2D and its adverse complications. With the aim of accelerating the investigation of complex natural sources, such as crude plant extracts, for potential PTP1B inhibitors, we have developed a bio-analytical platform combining high-resolution PTP1B inhibition profiling and high-performance liquid chromatography-high-resolution mass spectrometry-solid-phase extraction-nuclear magnetic resonance spectroscopy, i.e., HR-bioassay/HPLC-HRMS-SPE-NMR. Human recombinant PTP1B enzyme was used for the microplate-based PTP1B inhibition assay, which was optimized for pH and substrate concentration to be compatible with rate measurements within the 10 min incubation time. Subsequently, analytical-scale HPLC-based microfractionation followed by colorimetric microplate-based PTP1B bioassaying enabled construction of a high-resolution inhibition profile corresponding to the HPLC profile. The high-resolution PTP1B inhibition profiling was validated using an artificial mixture of known PTP1B inhibitors and non-inhibiting compounds as negative controls. Finally, a proof-of-concept study with a real sample was performed using crude ethyl acetate extract of the phytochemically hitherto unexplored plant Eremophila lucida. This led to the identification of the first viscidane type diterpene, i.e., 5-hydroxyviscida-3,14-dien-20-oic acid (9) as PTP1B inhibitor with an IC50 value of 42.0 ± 5.9 μM. In addition, a series of flavonoids, i.e., luteolin (1), dinatin (3a), tricin (3b), 3,6-dimethoxyapigenin (4), jaceidin (5), and cirsimaritin (6) as well as a cembrene diterpene, (3Z, 7E, 11Z)-15-hydroxycembra-3,7,11-trien-19-oic acid (8), were also identified for the first time from E. lucida.

Worldwide, 463 million people are affected by diabetes of which the majority is diagnosed with Type 2 Diabetes (T2D). T2D can ultimately lead to retinopathy, nephropathy, nerve damage, and amputation of the lower extremities. α-Glucosidase, responsible for converting starch to monosaccharides, is a key therapeutic target for the management of T2D. However, due to substantial side effects of currently marketed drugs, there is an urgent need for the discovery of new α-glucosidase inhibitors. In our ongoing efforts to identify novel α-glucosidase inhibitors from Nature, we are investigating the potential of endophytic filamentous fungi as sustainable sources of hits and/or leads for future antihyperglycemic drugs. Here we report one previously unreported xanthone (5) and two known xanthones (7 and 11) as α-glucosidase inhibitors, isolated from an endophytic Penicillium canescens, recovered from fruits of Juniperus polycarpos. The three xanthones 5, 7, and 11 showed inhibitory activities against α-glucosidase with IC50 values of 38.80 ± 1.01 μM, 32.32 ± 1.01 μM, and 75.20 ± 1.02 μM, respectively. Further pharmacological characterization revealed a mixed-mode inhibition for 5, a competitive inhibition for 7, while 11 acted as a non-competitive inhibitor.

Recent discovery of potent antibacterial antisense PNA-peptide conjugates encouraged development of a fast and efficient synthesis protocol that facilitates structure-activity studies. The use of an Fmoc/Boc protection scheme for both PNA monomers and amino acid building blocks in combination with microwave-assisted solid-phase synthesis proved to be a convenient procedure for continuous assembly of antisense PNA-peptide conjugates. A validated antisense PNA oligomer (CTCATACTCT; targeting mRNA of the acpP gene) was linked to N-terminally modified drosocin (i.e., RXR-PRPYSPRPTSHPRPIRV; X = aminohexanoic acid) or to a truncated Pip1 peptide (i.e., RXRRXR-IKILFQNRRMKWKK; X = aminohexanoic acid), and determination of the antibacterial effects of the resulting conjugates allowed assessment of the influence of different linkers as well as differences between the L- and D-forms of the peptides. The drosocin-derived compound without a linker moiety exhibited highest antibacterial activity against both wild-type Escherichia coli and Klebsiella pneumoniae (MICs in the range 2–4 μg/mL ∼ 0.3–0.7 μM), while analogues displaying an ethylene glycol (eg1) moiety or a polar maleimide linker also possessed activity toward wild-type K. pneumoniae (MICs of 4–8 μg/mL ∼ 0.6–1.3 μM). Against two colistin-resistant E. coli strains the linker-deficient compound proved most potent (with MICs in the range 2–4 μg/mL ∼ 0.3–0.7 μM). The truncated all-L Pip1 peptide had moderate inherent activity against E. coli, and this was unaltered or reduced upon conjugation to the antisense PNA oligomer. By contrast, this peptide was 8-fold less potent against K. pneumoniae, but in this case some PNA-peptide conjugates exhibited potent antisense activity (MICs of 2–8 μg/mL ∼ 0.3–1.2 μM). Most interestingly, the antibacterial activity of the D-form peptide itself was 2- to 16-fold higher than that of the L-form, even for the colistin- and tigecycline-resistant E. coli strains (MIC of 1–2 μg/mL ∼ 0.25–0.5 μM). Low activity was found for conjugates with a two-mismatch PNA sequence corroborating an antisense mode of action. Conjugates containing a D-form peptide were also significantly less active. In conclusion, we have designed and synthesized antisense PNA-drosocin conjugates with potent antibacterial activity against colistin- and tigecycline-resistant E. coli and K. pneumonia without concomitant hemolytic properties. In addition, a truncated D-form of Pip1 was identified as a peptide exhibiting potent activity against both wild-type and multidrug-resistant E. coli, P. aeruginosa, and A. baumannii (MICs within the range 1–4 μg/mL ∼ 0.25–1 μM) as well as toward wild-type Staphylococcus aureus (MIC of 2–4 μg/mL ∼ 0.5–1.0 μM).

In our ongoing efforts of finding natural fungicides to fight food and feed spoilage during production and storage, the antifungal potential of Ghanaian Uvaria chamae P. Beauv. was investigated, with emphasis on plant metabolites targeting the fungal plasma membrane (PM) H + -ATPase. Ethyl acetate extract of U. chamae was subjected to high-resolution fungal PM H + -ATPase inhibition screening followed by structural elucidation by high-performance liquid chromatography–high-resolution mass spectrometry–solid-phase extraction–nuclear magnetic resonance spectroscopy (HPLC–HRMS–SPE–NMR). This led to identification of a series of uncommon o -hydroxybenzylated flavanones and chalcones, i.e., chamanetin ( 8 ), isochamanetin ( 9 ), isouvaretin ( 10 ), uvaretin ( 11 ), dichamanetin ( 12 ), and diuvaretin ( 15 ). Preparative-scale isolation of the active metabolites allowed determination of IC 50 values for inhibition of the PM H + -ATPase, and growth inhibition of Saccharomyces cerevisiae and Candida albicans . These revealed a strong correlation between o -hydroxybenzyl substituents and PM H + -ATPase activity, with dichamanetin being the most potent compound, but showing moderate activity in the fungal growth inhibition assays.

The crude methanol extract of Pueraria lobata was investigated by dual high-resolution α-glucosidase inhibition and radical scavenging profiling combined with hyphenated HPLC-HRMS-SPE-NMR. Direct analysis of the crude extract without preceding purification was facilitated by combining chromatograms from two analytical-scale HPLC separations of 120 and 600 μg on-column, respectively. High-resolution α-glucosidase and radical scavenging profiles were obtained after microfractionation of the eluate in 96-well microplates. This allowed full bioactivity profiling of individual peaks in the HPLC chromatogram of the crude methanol extract. Subsequent HPLC-HRMS-SPE-NMR analysis allowed identification of 21 known compounds in addition to two new compounds, i.e., 3'-methoxydaidzein 8-C-[α-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside and 6″-O-malonyl-3'-methoxydaidzin, as well as an unstable compound tentatively identified as 3'-de-O-methylpuerariafuran.

This work describes an analytical platform based on semi-high-resolution antileishmanial profiling combined with hyphenation of high-performance liquid chromatography – high-resolution mass spectrometry – solid-phase extraction – nuclear magnetic resonance spectroscopy, i.e., semiHR-antileishmanial assay/HPLC-HRMS-SPE-NMR. The platform enables fast pinpointing of HPLC peaks representing Leishmania tropica inhibitors in complex matrices, with subsequent structural identification of targeted inhibitors. Active analytes were cumulatively trapped on SPE cartridges and the structures elucidated by analysis of NMR spectra obtained in the HPLC-HRMS-SPE-NMR mode. This led to the identification of six known compounds 2,4,6-trihydroxyacetophenone-2-O-β-D-glucopyranoside (1), lalioside (2), luteolin-4′-O-β-D-glucopyranoside (3), apigenin-4′-O-β-D-glucopyranoside (4), luteolin (5), and apigenin (6). IC50 of the active compounds were determined with luteolin being the most potent inhibitor with an IC50 value of 4.15 μg/ml. The platform proved to be an efficient method for the identification of L. tropica inhibitors.

According to the International Diabetes Federation, type 2 diabetes (T2D) has reached epidemic proportions, affecting more than 382 million people worldwide. Inhibition of protein tyrosine phosphatase-1B (PTP1B) and α-glucosidase is a recognized therapeutic approach for management of T2D and its associated complications. The lack of clinical drugs targeting PTP1B and side effects of the existing α-glucosidase drugs, emphasize the need for new drug leads for these T2D targets. In the present work, dual high-resolution PTP1B and α-glucosidase inhibition profiles of Eremophila gibbosa, E. glabra, and E. aff. drummondii "Kalgoorlie" were used for pinpointing α-glucosidase and/or PTP1B inhibitory constituents directly from the crude extracts. A subsequent targeted high-performance liquid chromatography-high-resolution mass spectrometry-solid-phase extraction-nuclear magnetic resonance spectroscopy (HPLC-HRMS-SPE-NMR) analysis and preparative-scale HPLC isolation led to identification of 21 metabolites from the three species, of which 16 were serrulatane-type diterpenoids (12 new) associated with either α-glucosidase and/or PTP1B inhibition. This is the first report of serrulatane-type diterpenoids as potential α-glucosidase and/or PTP1B inhibitors.

1. The metabolism of midazolam was investigated in vivo in locusts in order to evaluate the presence of an enzyme with functionality similar to human CYP3A4/5. 2. Hydroxylated metabolites of midazolam identical to human metabolites were detected in locusts and the apparent affinities (Km values) were in the same range as reported in humans (in locusts: 7–23 and 33–85 µM for the formation of the 1′-OH and 4-OH metabolites, respectively). 3. The formation of hydroxylated metabolites could successfully be inhibited by co-administration of ketoconazole, a known CYP3A4/5 inhibitor. 4. Besides phase I metabolites, a number of conjugated metabolites were detected using high-resolution mass spectrometry. The most abundant metabolites detected were structurally identified by 1H NMR as two N-glucosides. NMR analysis strongly suggested that the glycosylation occurred at the two nitrogens (either one in each case) of the imidazole ring. 5. Distribution of midazolam and the glucose conjugates were successfully measured using desorption electrospray mass spectrometry imaging revealing time-dependent changes in distribution over time. 6. In conclusion, it appears that an enzyme with functionality similar to human CYP3A4/5 is present in locusts. However, it appears that conjugation with glucose is the main detoxification pathway of midazolam in locusts.

A series of bioisosteric N1- and N2 -substituted 5-(piperidin-4-yl)-3-hydroxypyrazole analogues of the partial GABAA R agonists 4-PIOL and 4-PHP have been designed, synthesized, and characterized pharmacologically. The unsubstituted 3-hydroxypyrazole analogue of 4-PIOL (2 a; IC50 ∼300 μM) is a weak antagonist at the α1 β2 γ2 GABAA R, whereas substituting the N1- or N2- position with alkyl or aryl substituents resulted in antagonists with binding affinities in the high nanomolar to low micromolar range at native rat GABAA Rs. Docking studies using a α1 β2 γ2 GABAA R homology model along with the obtained SAR indicate that the N1 -substituted analogues of 4-PIOL and 4-PHP, 2 a-k, and previously reported 3-substituted 4-PHP analogues share a common binding mode to the orthosteric binding site in the receptor. Interestingly, the core scaffold of the N2 -substituted analogues of 4-PIOL and 4-PHP, 3 b-k, are suggested to flip 180° thereby adapting to the binding pocket and addressing a cavity situated above the core scaffold.