Preparation of dearomatized p-coumaric acid derivatives as DNA damage response inhibitors with potent in vitro antitumor effect.

Our research group previously identified graviquinone (1) as a promising antitumor metabolite that is formed in situ when the antioxidant methyl caffeate scavenges free radicals. Furthermore, it exerted a DNA damaging effect on cancer cells and a DNA protective effect on normal keratinocytes. To expand and explore chemical space around qraviquinone, in the current work we synthesized 9 new alkyl-substituted derivatives and tested their in vitro antitumor potential. All new compounds bypassed ABCB1-mediated multidrug resistance and showed highly different cell line specificity compared with 1. All compounds were more potent in MDA-MB-231 than on MCF-7 cells. The n-butyl-substituted derivatives 2 and 8 modulated the cell cycle and inhibited the ATR-mediated phosphorylation of checkpoint kinase-1 in MCF-7 cells. As a significant expansion of our previous findings, our results highlight the potential antitumor value of alkyl-substituted graviquinone derivatives.

Nimodipine inhibits spreading depolarization, ischemic injury, and neuroinflammation in mouse live brain slice preparations.

Nimodipine is used to prevent delayed ischemic deficit in patients with aneurysmal subarachnoid hemorrhage (aSAH). Spreading depolarization (SD) is recognized as a factor in the pathomechanism of aSAH and other acute brain injuries. Although nimodipine is primarily known as a cerebral vasodilator, it may have a more complex mechanism of action due to the expression of its target, the L-type voltage-gated calcium channels (LVGCCs) in various cells in neural tissue. This study was designed to investigate the direct effect of nimodipine on SD, ischemic tissue injury, and neuroinflammation. SD in control or nimodipine-treated live mouse brain slices was induced under physiological conditions using electrical stimulation, or by subjecting the slices to hypo-osmotic stress or mild oxygen-glucose deprivation (mOGD). SD was recorded applying local field potential recording or intrinsic optical signal imaging. Histological analysis was used to estimate tissue injury, the number of reactive astrocytes, and the degree of microglia activation. Nimodipine did not prevent SD occurrence in mOGD, but it did reduce the rate of SD propagation and the cortical area affected by SD. In contrast, nimodipine blocked SD occurrence in hypo-osmotic stress, but had no effect on SD propagation. Furthermore, nimodipine prevented ischemic injury associated with SD in mOGD. Nimodipine also exhibited anti-inflammatory effects in mOGD by reducing reactive astrogliosis and microglial activation. The results demonstrate that nimodipine directly inhibits SD, independent of nimodipine's vascular effects. Therefore, the use of nimodipine may be extended to treat acute brain injuries where SD plays a central role in injury progression.

Liquid Chromatographic Enantioseparation of Newly Synthesized Fluorinated Tryptophan Analogs Applying Macrocyclic Glycopeptides-Based Chiral Stationary Phases Utilizing Core-Shell Particles.

Due to the favorable features obtained through the incorporation of fluorine atom(s), fluorinated drugs are a group with emerging pharmaceutical importance. As their commercial availability is still very limited, to expand the range of possible candidates, new fluorinated tryptophan analogs were synthesized. Control of enantiopurity during the synthesis procedure requires that highly efficient enantioseparation methods be available. In this work, the enantioseparation of seven fluorinated tryptophans and tryptophan was studied and compared systematically to (i) develop analytical methods for enantioselective separations and (ii) explore the chromatographic features of the fluorotrytophans. For enantioresolution, macrocyclic glycopeptide-based selectors linked to core-shell particles were utilized, applying liquid chromatography-based methods. Application of the polar-ionic mode resulted in asymmetric and broadened peaks, while reversed-phase conditions, together with mobile-phase additives, resulted in baseline separation for all studied fluorinated tryptophans. The marked differences observed between the methanol and acetonitrile-containing eluent systems can be explained by the different solvation abilities of the bulk solvents of the applied mobile phases. Among the studied chiral selectors, teicoplanin and teicoplanin aglycone were found to work effectively. Under optimized conditions, baseline separations were achieved within 6 min. Ionic interactions were semi-quantitatively characterized and found to not influence enantiorecognition. Interestingly, fluorination of the analytes does not lead to marked changes in the chromatographic characteristics of the methanol-containing eluents, while larger differences were noticed when the polar but aprotic acetonitrile was applied. Experiments conducted on the influence of the separation temperature indicated that the separations are enthalpically driven, with only one exception. Enantiomeric elution order was found to be constant on both teicoplanin and teicoplanin aglycone-based chiral stationary phases (L < D) under all applied chromatographic conditions.

17-Oxime ethers of oxidized ecdysteroid derivatives modulate oxidative stress in human brain endothelial cells and dose-dependently might protect or damage the blood-brain barrier.

20-Hydroxyecdysone and several of its oxidized derivatives exert cytoprotective effect in mammals including humans. Inspired by this bioactivity of ecdysteroids, in the current study it was our aim to prepare a set of sidechain-modified derivatives and to evaluate their potential to protect the blood-brain barrier (BBB) from oxidative stress. Six novel ecdysteroids, including an oxime and five oxime ethers, were obtained through regioselective synthesis from a sidechain-cleaved calonysterone derivative 2 and fully characterized by comprehensive NMR techniques revealing their complete 1H and 13C signal assignments. Surprisingly, several compounds sensitized hCMEC/D3 brain microvascular endothelial cells to tert-butyl hydroperoxide (tBHP)-induced oxidative damage as recorded by impedance measurements. Compound 8, containing a benzyloxime ether moiety in its sidechain, was the only one that exerted a protective effect at a higher, 10 µM concentration, while at lower (10 nM- 1 µM) concentrations it promoted tBHP-induced cellular damage. Brain endothelial cells were protected from tBHP-induced barrier integrity decrease by treatment with 10 µM of compound 8, which also mitigated the intracellular reactive oxygen species production elevated by tBHP. Based on our results, 17-oxime ethers of oxidized ecdysteroids modulate oxidative stress of the BBB in a way that may point towards unexpected toxicity. Further studies are needed to evaluate any possible risk connected to dietary ecdysteroid consumption and CNS pathologies in which BBB damage plays an important role.

Thymoquinone-protoflavone hybrid molecules as potential antitumor agents.

We describe herein the synthesis of eight new ester-coupled hybrid compounds from thymoquinone and protoflavone building blocks, and their bioactivity testing against multiple cancer cell lines. Among the hybrids, compound 14 showed promising activities in all cell lines studied. The highest activities were recorded against breast cancer cell lines with higher selectivity to MDA-MB-231 as compared to MCF-7. Even though the hybrids were found to be completely hydrolysed in 24 h under cell culture conditions, compound 14 demonstrated a ca. three times stronger activity against U-87 glioblastoma cells than a 1:1 mixture of its fragments. Further, compound 14 showed good tumour selectivity: it acted 4.4-times stronger on U-87 cells than on MRC-5 fibroblasts. This selectivity was much lower, only ca. 1.3-times, when the cells were co-treated with a 1:1 mixture of its non-coupled fragments. Protoflavone-thymoquinone hybrids may therefore serve as potential new antitumor leads particularly against glioblastoma.

Rapid Detection of Adulteration in Boswellia Extracts with Citric Acid by UPLC-HRMS and 1H NMR.

Boswellia serrata ole-gum-resin extracts (BSEs) are commonly used as food supplements, especially in osteoarthritis management. The quality standard is established by determining 11-keto-ß-boswellic acid (KBA) and acetyl-11-keto-boswellic acid (AKBA) content using high-performance liquid chromatography (HPLC) or assessing the total boswellic acid (TBA) content by titrimetry. The limited geographical distribution of Boswellia species and increasing industrial demand could increase the risk of adulteration in Boswellia-containing products. In this study, 14 BSEs from commercial sources, used in food supplements, were analyzed in comparison with a USP Reference Standard extract. The KBA and AKBA content was determined by HPLC, whereas the TBA content was determined by titration. Targeted UHPLC-high-resolution mass spectrometry (HRMS) was applied to identify the carboxylic acid content in the samples. The 1H NMR spectra of extracts were also analyzed. Only two products met the criteria for KBA and AKBA content. Although, the TBA content complied with the expected amount, 10 extracts contained citric acid levels of 6-11% even though citric acid is not a cha-racteristic component of BSEs. Our results suggest undeclared addition of citric acid to comply with declared contents of TBA when using titration methods. Incorporation of citric acid to industrial samples - in order to alter the outcomes of the titration analysis - was demonstrated for the first time.

High-performance liquid chromatographic enantioseparation of azole analogs of monoterpene lactones and amides focusing on the separation characteristics of polysaccharide-based chiral stationary phases.

High-performance liquid chromatography-based enantioseparation of newly prepared azole analogs of monoterpene lactones and amides was studied. Effects of additives and mobile phase composition were evaluated both in normal and polar organic modes. Applying amylose tris-(3,5-dimethylphenylcarbamate) selector in normal and polar organic modes acid and base additives were found to affect the peak profiles, without significantly influencing the enantiorecognition ability of the studied selector. In most cases, differences observed in retention times and enantioselectivities were lower than 10 and 20 % under normal phase and polar organic conditions, respectively. Under normal phase conditions decreased retention was observed for all the studied analytes with increased eluent polarity. Interestingly, enantioselectivity was only slightly (<10 %) influenced by the variation in the n-hexane/2-propanol ratio between 80/20 and 20/80 v/v. In polar organic mode, five different neat solvents (acetonitrile, methanol, ethanol, 1-propanol, and 2-propanol) were tested, and the best results were obtained with acetonitrile and ethanol in the case of Lux Amylose-1 column with enantioresolutions most often above 2. Based on results obtained with amylose and cellulose-based columns the amylose tris-(3,5-dimethylphenylcarbamate) selector is found to offer a superior performance both in normal and polar organic modes. When evaluating the possible effects of the selector immobilization, no striking differences were found in the normal phase. Usually, enantioselectivities and resolutions were higher (10-20 %), while retention factors of the first peaks were lower (20-30 %), on the coated-type column. In contrast, in polar organic mode, the retention characteristics and enantiorecognition ability of the coated and immobilized selectors were heavily affected by the nature of the polar solvent. Special attention has been paid to the history-dependent behavior of polysaccharide-based selectors. A confidence interval-based evaluation is suggested to help comparison of the histereticity observed in different systems. Several examples are shown to confirm that the recently discovered hysteresis is a common characteristic of polysaccharide-based selectors.

Furanonaphthoquinones, Diterpenes, and Flavonoids from Sweet Marjoram and Investigation of Antimicrobial, Bacterial Efflux, and Biofilm Formation Inhibitory Activities.

The chloroform extract of Origanum majorana exhibited high antibacterial and antifungal activities against 12 bacterial and 4 fungal strains; therefore, it was subjected to bioassay-guided isolation to afford six compounds (1-6). The structures were determined via one- and two-dimensional nuclear magnetic spectroscopy and high-resolution electrospray ionization mass spectrometry experiments. The compounds were identified as furanonaphthoquinones [majoranaquinone (1), 2,3-dimethylnaphtho[2,3-b]furan-4,9-dione (2)], diterpenes [19-hydroxyabieta-8,11,13-trien-7-one (3), 13,14-seco-13-oxo-19-hydroxyabieta-8-en-14-al (4)], and flavonoids [sterubin (5) and majoranin (6)]. Compounds 1 and 2 were first obtained from a natural source and compounds 3 and 4 were previously undescribed. Majoranaquinone (1) exhibited a high antibacterial effect against 4 Staphylococcus, 1 Moraxella, and 1 Enterococcus strains (MIC values between 7.8 µM and 1 mM). In the efflux pump inhibition assay, majoranaquinone (1) showed substantial activity in Escherichia coli ATCC 25922 strain. Furthermore, 1 was found to be an effective biofilm formation inhibitor on E. coli ATCC 25922 and E. coli K-12 AG100 bacteria. Our findings proved that bioactivities of majoranaquinone (1) significantly exceed those of the essential oil constituents; therefore, it should also be considered when assessing the antimicrobial effects of O. majorana.

Differential Effects of Hypothermia and SZR72 on Cerebral Kynurenine and Kynurenic Acid in a Piglet Model of Hypoxic-Ischemic Encephalopathy.

Kynurenic acid (KYNA), an endogenous neuroprotectant with antiexcitotoxic, antioxidant, and anti-inflammatory effects, is synthesized through the tryptophan-kynurenine (KYN) pathway. We investigated whether brain KYN or KYNA levels were affected by asphyxia in a translational piglet model of hypoxic-ischemic encephalopathy (HIE). We also studied brain levels of the putative blood-brain barrier (BBB) permeable neuroprotective KYNA analogue SZR72, and whether SZR72 or therapeutic hypothermia (TH) modified KYN or KYNA levels. KYN, KYNA, and SZR72 levels were determined using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry in five brain regions 24 h after 20 min of asphyxia in vehicle-, SZR72- and TH-treated newborn piglets (n = 6-6-6) and naive controls (n = 4). Endogenous brain KYN levels (median range 311.2-965.6 pmol/g) exceeded KYNA concentrations (4.5-6.0 pmol/g) ~100-fold. Asphyxia significantly increased cerebral KYN and KYNA levels in all regions (1512.0-3273.9 and 16.9-21.2 pmol/g, respectively), increasing the KYN/Tryptophan-, but retaining the KYNA/KYN ratio. SZR72 treatment resulted in very high cerebral SZR72 levels (13.2-33.2 nmol/g); however, KYN and KYNA levels remained similar to those of the vehicle-treated animals. However, TH virtually ameliorated asphyxia-induced elevations in brain KYN and KYNA levels. The present study reports for the first time that the KYN pathway is altered during HIE development in the piglet. SZR72 readily crosses the BBB in piglets but fails to affect cerebral KYNA levels. Beneficial effects of TH may include restoration of the tryptophan metabolism to pre-asphyxia levels.

Anticancer Meroterpenoids from Centrapalus pauciflorus leaves: Chromone- and 2,4-Chromadione-Monoterpene Derivatives.

Eight previously undescribed chromones, named pauciflorins F-M and two 5-methyl-2,4-chromadione derivatives named as pauciflorins N and O, were isolated from the methanol extract of the leaves of Centrapalus pauciflorus (Willd.) H.Rob. together with the known (+)-spiro-ethuliacoumarin. The structures were determined via extensive spectroscopic analyses, including HRESIMS, 1D NMR (1H, 13C JMOD), and 2D NMR (HSQC, HMBC, 1H-1H COSY, and NOESY) experiments. Through an MTT assay, seven isolated compounds were tested for their antiproliferative properties against human adherent breast (MCF-7, MDA-MB-231), cervical (HeLa, SiHa), and ovarian (A2780) cancer cell lines. Pauciflorin F was effective against MCF-7 breast cancer cells, its activity (IC50 5.78 µM) was comparable to that of the reference agent cisplatin (IC50 5.78 µM).

Focusing on the 5F-MDMB-PICA, 4F-MDMB-BICA synthetic cannabinoids and their primary metabolites in analytical and pharmacological aspects.

Nowadays, more and more new synthetic cannabinoids (SCs) appearing on the illicit market present challenges to analytical, forensic, and toxicology experts. For a better understanding of the physiological effect of SCs, the key issue is studying their metabolomic and psychoactive properties. In this study, our validated targeted reversed phase UHPLC-MS/MS method was used for determination of urinary concentration of 5F-MDMB-PICA, 4F-MDMB-BICA, and their primary metabolites. The liquid-liquid extraction procedure was applied for the enrichment of SCs. The pharmacological characterization of investigated SCs were studied by radioligand competition binding and ligand stimulated [35S]GTPγS binding assays. For 5F-MDMB-PICA and 4F-MDMB-BICA, the median urinary concentrations were 0.076 and 0.312 ng/mL. For primary metabolites, the concentration range was 0.029-881.02* ng/mL for 5F-MDMB-PICA-COOH, and 0.396-4579* ng/mL for 4F-MDMB-BICA-COOH. In the polydrug aspect, the 22 urine samples were verified to be abused with 6 illicit drugs. The affinity of the metabolites to CB1R significantly decreased compared to the parent ligands. In the GTPγS functional assay, both 5F-MDMB-PICA and 4F-MDMB-BICA were acting as full agonists, while the metabolites were found as weak inverse agonists. Additionally, the G-protein stimulatory effects of the full agonist 5F-MDMB-PICA and 4F-MDMB-BICA were reduced by metabolites. These results strongly indicate the dose-dependent CB1R-mediated weak inverse agonist effects of the two butanoic acid metabolites. The obtained high concentration of main urinary metabolites of 5F-MDMB-PICA and 4F-MDMB-BICA confirmed the relevance of their routine analysis in forensic and toxicological practices. Based on in vitro binding assays, the metabolites presumably might cause a lower psychoactive effect than parent compounds.

Enantioseparation of a-substituted proline analogs with macrocyclic glycopeptide-based chiral stationary phases immobilized on superficially porous particles of silica applying liquid chromatography with ultraviolet and mass spectrometric detection.

In this study, the liquid chromatography-based direct enantioseparation of the stereoisomers of α-substituted proline analogs has been investigated utilizing chiral stationary phases with UV and/or mass spectrometric (MS) detection. Macrocyclic antibiotics, such as vancomycin, teicoplanin, modified teicoplanin, and teicoplanin aglycone, all covalently immobilized to 2.7 µm superficially porous silica particles have been applied as stationary phases. Mobile phases utilizing mixtures of methanol and acetonitrile with different additives (polar-ionic mode) were optimized during method development. Best separations were achieved with mobile phases of 100% MeOH containing either 20 mM acetic acid or 20 mM triethylammonium acetate. Special attention was given to the applicability of MS-compatible mobile phases. Acetic acid was found to be advantageous as a mobile phase additive for MS detection. Enantioselective chromatographic behaviors are interpreted based on the explored correlations between the analytes' structural features and those of the applied chiral stationary phases. For the thermodynamic characterization, separations were studied in the temperature range of 5-50 °C. Generally, retention and selectivity decreased with increasing temperature, and in most cases, enthalpy-driven enantiorecognition was observed, but entropic contributions also were present. Unexpectedly, unusual shapes for the van Deemter curves were registered in the kinetic evaluations. General trends could be observed in the enantiomeric elution orders: S < R on VancoShell and NicoShell, and opposite R < S on TeicoShell and TagShell columns.

Pauciflorins A-E, Unexpected Chromone-Monoterpene-Derived Meroterpenoids from Centrapalus pauciflorus.

Five unusual meroterpenoids based on new carbon skeletons, pauciflorins A-E (1-5), were isolated by multistep chromatographic separations of a methanol extract of the aerial parts of Centrapalus pauciflorus. Compounds 1-3 are derived by the connection of a 2-nor-chromone and a monoterpene unit, whereas 4 and 5 are dihydrochromone-monoterpene adducts with a rarely occurring orthoester functionality. The structures were solved using 1D and 2D NMR, HRESIMS, and single-crystal X-ray diffraction. Pauciflorins A-E were evaluated for antiproliferative activity against human gynecological cancer cell lines, but were inactive (IC50 < 10 µM) in each case.

Preparation and Evaluation of 6-Gingerol Derivatives as Novel Antioxidants and Antiplatelet Agents.

Ginger (Zingiber officinale) is widely used as a spice and a traditional medicine. Many bioactivities have been reported for its extracts and the isolated compounds, including cardiovascular protective effects. Different pathways were suggested to contribute to these effects, like the inhibition of platelet aggregation. In this study, we synthesised fourteen 6-gingerol derivatives, including eight new compounds, and studied their antiplatelet, COX-1 inhibitor, and antioxidant activities. In silico docking of selected compounds to h-COX-1 enzyme revealed favourable interactions. The investigated 6-gingerol derivatives were also characterised by in silico and experimental physicochemical and blood-brain barrier-related parameters for lead and preclinical candidate selection. 6-Shogaol (2) was identified as the best overall antiplatelet lead, along with compounds 3 and 11 and the new compound 17, which require formulation to optimize their water solubility. Compound 5 was identified as the most potent antioxidant that is also promising for use in the central nervous system (CNS).

Isolation of the Lanostane Triterpenes Pholiols L-S from Pholiota populnea and Evaluation of Their Antiproliferative and Cytotoxic Activities.

Pholiols L-S (1−8), eight undescribed triterpenes were isolated from the sporocarps of the mushroom Pholiota populnea. Various chromatographic techniques, such as open column chromatography, flash chromatography, gel filtration, preparative thin layer chromatography, and HPLC, were applied to purify the compounds. The structure elucidation was carried out by spectroscopic analysis, including 1D (1H NMR and 13C JMOD) and 2D NMR (1H-1H COSY, HSQC, HMBC and NOESY) and HRESIMS experiments. The isolated compounds had lanostane (1−7) or trinorlanostane (8) skeletons; all of them were substituted with 3-hydroxy-3-methylglutaroyl group or its 6-methyl ester. Five compounds (1, 2, 4, 6, and 8) were investigated for their antiproliferative and cytotoxic activity in vitro by MTT assay on breast cancer (MCF-7), human colon adenocarcinoma (sensitive Colo 205, and resistant Colo 320), non-small cell lung cancer (A549), and human embryonic lung fibroblast (MRC-5) cell lines. Pholiols M (2) and O (4) showed antiproliferative activity against the MCF-7 cell line with IC50 of 2.48 and 9.95 µM, respectively. These compounds displayed tumor cell selectivity on MCF-7 cells with SI values of >40 (2) and 4.3 (4), but they did not show a cytotoxic effect, proving their action exclusively on tumor cell proliferation. Pholiols L (1) and Q (8) were found to have selective cytotoxicity on drug resistant cells in comparison to their effects on Colo320 and Colo205 cells [relative resistance values 0.84 (1) and 0.62 (8)].

Pholiols E-K, lanostane-type triterpenes from Pholiota populnea with anti-inflammatory properties.

Investigation of the chloroform and ethyl acetate extracts of the edible mushroom Pholiota populnea led to the isolation of eight triterpenes, the undescribed natural products pholiols E-K and the known (+)-clavaric acid. HRESIMS and 1D and 2D NMR spectroscopy were employed to determine the structures of the undescribed compounds. The NOESY spectra were used to assign the relative configurations of triterpenes. The isolated compounds were screened for their anti-inflammatory activity on cyclooxygenase (COX-1 and COX-2), and lipoxygenase (5-LOX and 15-LOX) inhibitory assays. Dose-response investigations revealed that lanostane derivatives exhibited moderate 5-LOX and COX-2 inhibitory activities, with pholiol F (IC50 194.5 µM against 5-LOX and 439.8 µM against COX-2) the most active among the isolated compounds. Our findings indicated that P. populnea is an abundant source of new bioactive lanostane-type triterpenes.

Oxidized Resveratrol Metabolites as Potent Antioxidants and Xanthine Oxidase Inhibitors.

Resveratrol is a well-known natural polyphenol with a plethora of pharmacological activities. As a potent antioxidant, resveratrol is highly oxidizable and readily reacts with reactive oxygen species (ROS). Such a reaction not only leads to a decrease in ROS levels in a biological environment but may also generate a wide range of metabolites with altered bioactivities. Inspired by this notion, in the current study, our aim was to take a diversity-oriented chemical approach to study the chemical space of oxidized resveratrol metabolites. Chemical oxidation of resveratrol and a bioactivity-guided isolation strategy using xanthine oxidase (XO) and radical scavenging activities led to the isolation of a diverse group of compounds, including a chlorine-substituted compound (2), two iodine-substituted compounds (3 and 4), two viniferins (5 and 6), an ethoxy-substituted compound (7), and two ethoxy-substitute,0d dimers (8 and 9). Compounds 4, 7, 8, and 9 are reported here for the first time. All compounds without ethoxy substitution exerted stronger XO inhibition than their parent compound, resveratrol. By enzyme kinetic and in silico docking studies, compounds 2 and 4 were identified as potent competitive inhibitors of the enzyme, while compound 3 and the viniferins acted as mixed-type inhibitors. Further, compounds 2 and 9 had better DPPH scavenging activity and oxygen radical absorbing capacity than resveratrol. Our results suggest that the antioxidant activity of resveratrol is modulated by the effect of a cascade of chemically stable oxidized metabolites, several of which have significantly altered target specificity as compared to their parent compound.

Ingol, ent-atisane, and stachane-type diterpenoids from Euphorbia deightonii with multidrug resistance reversing activity.

Nine previously undescribed ingol-type diterpenoid polyesters with eighteen known ingol esters, two ent-atisane, and one stachane diterpenoid were isolated from the methanol extract of Euphorbia deightonii Croizat. The structures were established by extensive spectroscopic analysis involving 1D (1H, 13C J-modulation) and 2D NMR experiments, HRESIMS measurements, and the comparison of the spectroscopic data with reported literature values. The cytotoxic concentrations of 13 isolated compounds were determined, and the compounds were investigated for multidrug resistance modulating activity on an L5178 mouse lymphoma cell line using a rhodamin 123 accumulation assay. Six ingol esters demonstrated the significant inhibition of P-glycoprotein, while the two ent-atisane diterpenoids were found to be inactive. The measured activities allowed to establish some structure-activity relationships. Notably, lower and higher-type diterpenoids simultaneously occurred in E. deightonii.

Macrocyclic glycopeptides- and derivatized cyclofructan-based chiral stationary phases for the enantioseparation of fluorinated ß-phenylalanine analogs.

The enantioseparation of five fluorinated ß-phenylalanine analogs together with the nonfluorinated α- and ß-phenylalanines has been investigated utilizing chiral stationary phases. The employed chiral selectors include macrocyclic antibiotics, such as vancomycin, teicoplanin, and teicoplanin aglycone, isopropyl carbamate functionalized cyclofructan-6, and Cinchona alkaloid-based tert.-butyl carbamate quinine, all covalently bonded to 2.7 µm superficially porous silica particles. The applied conditions included reversed-phase and polar-ionic modes where the vancomycin-, and the cyclofructan-6-based core-shell particles proved to offer suitable efficiency. Under reversed-phase conditions typical hydrophobic chromatographic behavior was observed, especially in the H2O/MeOH system. The improved selectivity with increasing MeOH content observed in polar ionic mode suggests that H-bonding may not play a major role in the chiral recognition. The stoichiometric displacement model was probed to gather information on the ionic interactions. The ion-exchange process was found to affect retention, but it has no essential contribution to chiral recognition. Without paying special attention to the optimization of the system volume of the UHPLC instrument plate heights varying in the range of 10-50 µm were obtained. In all cases, retention and selectivity decreased with increasing temperature, and enthalpy-driven enantiorecognition was observed. Elution sequences were determined in all cases.

Polyoxypregnane Ester Derivatives and Lignans from Euphorbia gossypina var. coccinea Pax.

From the aerial parts of Euphorbiagossypina var. coccinea Pax., eight new pregnane glycosides (euphogossypins A-H, 1-8) of the cynanforidine and deacetylmetaplexigenin aglycons, two new lignans (gossypilignans A and B, 9 and 10), and four known compounds, namely, the pregnane 12-O-benzoyldeaxcylmetaplexigenin (11), the lignan 9α-hydroxypinoresinol (12), and the flavonoids naringenin (13) and quercitrin (14) were isolated. The structure elucidation of the new compounds was carried out by a spectroscopic analysis, including HRMS, 1D (1H, 13C JMOD), and 2D NMR (HSQC, 1H-1H COSY, HMBC, and NOESY) experiments. The obtained pregnane glycosides were substituted with acetyl and benzoyl ester moieties, and sugar chains containing thevetose, cymarose, digitoxose, and glucose monosaccharides. All of the compounds are described for the first time from E. gossypina var. coccinea. The isolated pregnanes and lignans were tested for their antiproliferative activity on HeLa cells using the MTT assay; the compounds exerted no significant effect against the tumor cells.