Pharmacokinetics of Ginsenoside Rb1, Rg3, Rk1, Rg5, F2, and Compound K from Red Ginseng Extract in Healthy Korean Volunteers.

Individual differences in ginsenoside pharmacokinetics following ginseng administration in humans are still unclear. We aimed to investigate the pharmacokinetic properties of various ginsenosides, including Rb1, Rg3, Rg5, Rk1, F2, and compound K (CK), after a single oral administration of red ginseng (RG) and bioconverted red ginseng extract (BRG). This was a randomized, open-label, single-dose, single-sequence crossover study with washout every 1 week, and 14 healthy Korean men were enrolled. All subjects were equally assigned to two groups and given RG or BRG capsules. The pharmacokinetic parameters of ginsenosides were measured from the plasma drug concentration-time curve of individual subjects. Ginsenosides Rg3, Rk1 + Rg5, F2, and CK in the BRG group showed a higher C max, AUC(0-t), and AUC(0-∞) and shorter T max (for CK) than those in the RG group. These results suggest that BRG may lead to a higher absorption rate of bioactive ginsenosides. This study provides valuable information on the pharmacokinetics of various bioactive ginsenosides, which is needed to enhance the therapeutic efficacy and pharmacological activity of ginseng.

An access to highly enantioenriched cis-3,5-disubstituted γ-lactones from α-bromoacetate and silyl enol ether.

A novel synthetic strategy for highly enantioenriched cis-3,5-disubstituted γ-lactones has been developed by the AgOTf-promoted nucleophilic substitution of α-bromoacetates with silyl enol ethers and subsequent reductive lactonization. The utility of this synthetic method was further demonstrated through the concise stereodivergent synthesis of cis- and trans-2,4-disubstituted tetrahydrofurans.

Redox-Active Tyrosine-Mediated Peptide Template for Large-Scale Single-Crystalline Two-Dimensional Silver Nanosheets.

Although self-assembly of various peptides has been widely applied, it is challenging to obtain single-crystalline and layer-by-layered nanostructures in a two-dimensional system. Here, we report a method for controlling the morphology and crystal growth at room temperature by a redox-active peptide template that can specifically co-assemble with metal ions. During the crystal growth, a silver ion-coordinated α-helical peptide (+3HN-YYACAYY-COO-) induces long-range atomic ordering at the air/water interface, which leads to multilayered single-crystalline silver nanosheets without an additional annealing process. Furthermore, this peptide template can facilitate efficient electron transfer between the independent metal nanosheets to improve electrochemical properties. We expect that this peptide template-based single-crystal growth method can be extended to synthesize other materials.

Friedel-Crafts alkylation with α-bromoarylacetates for the preparation of enantioenriched 2,2-diarylethanols.

Highly enantioenriched 2,2-diarylethanols can be efficiently synthesized through the Friedel-Crafts alkylation of (hetero)arenes with configurationally labile α-bromoarylacetates. The substitution of highly diastereoenriched α-bromoarylacetates occurs in the presence of AgOTf, and the subsequent reduction affords diverse 2,2-diarylethanols with high yields and enantioselectivities up to 99 : 1 er. In addition, the application of this asymmetric synthetic methodology to the preparation of highly enantioenriched dihydrobenzofuran and indoline derivatives is demonstrated.

Development and Validation of a Novel Plasma Protein Signature for Breast Cancer Diagnosis by Using Multiple Reaction Monitoring-based Mass Spectrometry.

AIM: We aimed to develop a plasma protein signature for breast cancer diagnosis by using multiple reaction monitoring (MRM)-based mass spectrometry. MATERIALS AND METHODS: Based on our previous studies, we selected 124 proteins for MRM. Plasma samples from 80 patients with breast cancer and 80 healthy women were used to develop a plasma proteomic signature by an MRM approach. The proteomic signature was then validated in plasma samples from 100 patients with breast cancer and 100 healthy women. RESULTS: A total of 56 proteins were optimized for MRM. In the verification cohort, 11 proteins exhibited significantly differential expression in plasma from patients with breast cancer. Three proteins (neural cell adhesion molecule L1-like protein, apolipoprotein C-1 and carbonic anhydrase-1) with highest statistical significance which gave consistent results for patients of stage I and II breast cancer were selected and a 3-protein signature was developed using binary logistic regression analysis [area under the curve (AUC)=0.851, sensitivity=80.6%]. The 3-protein signature showed similar performance in an independent validation cohort with an AUC of 0.797 and sensitivity of 77.2% for detection of stage I and II breast cancer. CONCLUSION: We developed a distinct plasma protein signature for breast cancer diagnosis based on an MRM-based approach, and the clinical value of the 3-protein signature was validated in an independent cohort.

Peptoid-Substituted Hybrid Antimicrobial Peptide Derived from Papiliocin and Magainin 2 with Enhanced Bacterial Selectivity and Anti-inflammatory Activity.

Antimicrobial peptides (AMPs) are important components of the host innate immune system. Papiliocin is a 37-residue AMP purified from larvae of the swallowtail butterfly Papilio xuthus. Magainin 2 is a 23-residue AMP purified from the skin of the African clawed frog Xenopus laevis. We designed an 18-residue hybrid peptide (PapMA) incorporating N-terminal residues 1-8 of papiliocin and N-terminal residues 4-12 of magainin 2, joined by a proline (Pro) hinge. PapMA showed high antimicrobial activity but was cytotoxic to mammalian cells. To decrease PapMA cytotoxicity, we designed a lysine (Lys) peptoid analogue, PapMA-k, which retained high antimicrobial activity but displayed cytotoxicity lower than that of PapMA. Fluorescent dye leakage experiments and confocal microscopy showed that PapMA targeted bacterial cell membranes whereas PapMA-k penetrated bacterial cell membranes. Nuclear magnetic resonance experiments revealed that PapMA contained an N-terminal α-helix from Lys(3) to Lys(7) and a C-terminal α-helix from Lys(10) to Lys(17), with a Pro(9) hinge between them. PapMA-k also had two α-helical structures in the same region connected with a flexible hinge residue at Nlys(9), which existed in a dynamic equilibrium of cis and trans conformers. Using lipopolysaccharide-stimulated RAW264.7 macrophages, the anti-inflammatory activity of PapMA and PapMA-k was confirmed by inhibition of nitric oxide and inflammatory cytokine production. In addition, treatment with PapMA and PapMA-k decreased the level of ultraviolet irradiation-induced expression of genes encoding matrix metalloproteinase-1 (MMP-1), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in human keratinocyte HaCaT cells. Thus, PapMA and PapMA-k are potent peptide antibiotics with antimicrobial and anti-inflammatory activity, with PapMA-k displaying enhanced bacterial selectivity.

Partially Oxidized Sub-10 nm MnO Nanocrystals with High Activity for Water Oxidation Catalysis.

The oxygen evolution reaction (OER) is considered a major bottleneck in the overall water electrolysis process. In this work, highly active manganese oxide nano-catalysts were synthesized via hot injection. Facile surface treatment generated Mn(III) species on monodisperse 10 nm MnO nanocrystals (NCs). Size dependency of MnO NCs on OER activity was also investigated. Surprisingly, the partially oxidized MnO NCs only required 530 mV @ 5 mA cm(-2) under near neutral conditions.

Tyrosine-mediated two-dimensional peptide assembly and its role as a bio-inspired catalytic scaffold.

In two-dimensional interfacial assemblies, there is an interplay between molecular ordering and interface geometry, which determines the final morphology and order of entire systems. Here we present the interfacial phenomenon of spontaneous facet formation in a water droplet driven by designed peptide assembly. The identified peptides can flatten the rounded top of a hemispherical droplet into a plane by forming a macroscopic two-dimensional crystal structure. Such ordering is driven by the folding geometry of the peptide, interactions of tyrosine and crosslinked stabilization by cysteine. We discover the key sequence motifs and folding structures and study their sequence-specific assembly. The well-ordered, densely packed, redox-active tyrosine units in the YYACAYY (H-Tyr-Tyr-Ala-Cys-Ala-Tyr-Tyr-OH) film can trigger or enhance chemical/electrochemical reactions, and can potentially serve as a platform to fabricate a molecularly tunable, self-repairable, flat peptide or hybrid film.

A new water oxidation catalyst: lithium manganese pyrophosphate with tunable Mn valency.

The development of a water oxidation catalyst has been a demanding challenge for the realization of overall water-splitting systems. Although intensive studies have explored the role of Mn element in water oxidation catalysis, it has been difficult to understand whether the catalytic capability originates mainly from either the Mn arrangement or the Mn valency. In this study, to decouple these two factors and to investigate the role of Mn valency on catalysis, we selected a new pyrophosphate-based Mn compound (Li2MnP2O7), which has not been utilized for water oxidation catalysis to date, as a model system. Due to the monophasic behavior of Li2MnP2O7 with delithiation, the Mn valency of Li(2-x)MnP2O7 (x = 0.3, 0.5, 1) can be controlled with negligible change in the crystal framework (e.g., volume change ~1%). Moreover, inductively coupled plasma mass spectrometry, X-ray photoelectron spectroscopy, ex-situ X-ray absorption near-edge structure, galvanostatic charging-discharging, and cyclic voltammetry analysis indicate that Li(2-x)MnP2O7 (x = 0.3, 0.5, 1) exhibits high catalytic stability without additional delithiation or phase transformation. Notably, we observed that, as the averaged oxidation state of Mn in Li(2-x)MnP2O7 increases from 2 to 3, the catalytic performance is enhanced in the series Li2MnP2O7 < Li(1.7)MnP2O7 < Li(1.5)MnP2O7 < LiMnP2O7. Moreover, Li2MnP2O7 itself exhibits superior catalytic performance compared with MnO or MnO2. Our study provides valuable guidelines for developing an efficient Mn-based catalyst under neutral conditions with controlled Mn valency and atomic arrangement.

Antimicrobial effect of 7-O-butylnaringenin, a novel flavonoid, and various natural flavonoids against Helicobacter pylori strains.

The antimicrobial effect of a novel flavonoid (7-O-butylnaringenin) on Helicobacter pylori 26695, 51, and SS1 strains and its inhibitory effect on the urease activity of the strains were evaluated and compared with those of several natural flavonoids. First, various flavonoids were screened for antimicrobial activities using the paper disc diffusion method. Hesperetin and naringenin showed the strongest antimicrobial effects among the natural flavonoids tested, and thus hesperetin and naringenin were selected for comparison with 7-O-butylnaringenin. The antimicrobial effect of 7-O-butylnaringenin was greater than that of the hesperetin and naringenin. H. pylori 51 was more sensitive to 7-O-butylnaringenin (2 log reduction of colony forming units, p < 0.05) than the other two strains at 200 µM. 7-O-Butylnaringenin also showed the highest inhibitory effect against urease activity of H. pylori. Morphological changes of H. pylori 26695 treated with these flavonoids indicated that both hesperetin and 7-O-butylnaringenin at 200 µM damaged the cell membranes.

[M(rac-N-benzyl Asp)(H2O)] (M = Co, Ni): noncentrosymmetric coordination polymeric chains with racemic chiral ligands.

The hydrothermal reaction of fumaric acid, benzylamine, and metal salts yielded M[(rac-N-benzyl-Asp)(H(2)O)] (M = Co, Ni), 1 and 2, and Ni[(rac-N-benzyl-Asp)(H(2)O)(3)]·H(2)O 3. Under mild hydrothermal conditions, Michael addition of benzylamine to fumaric acid led to the formation of a racemic mixture of N-benzyl aspartic acid enantiomers. The noncentrosymmetric structures of 1 and 2 consist of one-dimensional polymeric chains in which metal cations are bridged by d- and l-N-benzyl aspartate anions alternating along the chain. The centrosymmetric structure of 3 is composed of discrete Ni[(rac-N-benzyl-Asp)(H(2)O)(3)] units that are connected by hydrogen bonds into layers. The single layers are homochiral but are hydrogen bonded to similar homochiral layers that contain the N-benzyl aspartate with the opposite handedness. Compounds 1 and 2 showed second harmonic generation (SHG), and their magnetic and thermodynamic properties are described.

Asymmetric synthesis of trans-2,3-disubstituted indoline derivatives.

A novel method for asymmetric synthesis of trans-2,3-disubstituted indolines has been developed. The strategy involves the (-)-sparteine-mediated electrophilic substitution of 2-benzyl N-pivaloylaniline with aromatic or α,ß-unsaturated aldehydes and subsequent intramolecular nucleophilic substitution. The simple protocol for two-step process can produce highly enantioenriched indolines 3a-o up to 98:2 er.

Antibody-free peptide substrate screening of serine/threonine kinase (protein kinase A) with a biotinylated detection probe.

Being different from anti-phosphotyrosine antibodies, anti-phosphoserine- or anti-phosphothreonine-specific antibodies with high affinity for the detection of serine/threonine kinase substrates are not readily available. Therefore, chemical modification methods were developed for the detection of phosphoserine or threonine in the screening of protein kinase substrates based on ß-elimination and Michael addition. We have developed a biotin-based detection probe for identification of the phosphorylated serine or threonine residue. A biotin derivative induced a color reaction using alkaline phosphate-conjugated streptavidin that amplified the signal. It was effective for the detection and separation of the target peptide on the resin. The detection probe was successfully used in identifying PKA substrates from peptide libraries on resin beads. The peptide library was prepared as a ladder-type, such that the active peptides on the colored resin beads were readily sequenced with the truncated peptide fragments by MALDI-TOF/MS analysis after releasing the peptides from the resin bead through photolysis.

Structural flexibility and the positive charges are the key factors in bacterial cell selectivity and membrane penetration of peptoid-substituted analog of Piscidin 1.

Piscidin 1 (Pis-1) is a novel cytotoxic peptide with a cationic alpha-helical structure isolated from the mast cells of hybrid striped bass. In our previous study, we showed that Pis-1[PG] with a substitution of Pro(8) for Gly(8) in Pis-1 had higher bacterial cell selectivity than Pis-1. We designed peptoid residue-substituted peptide, Pis-1[NkG], in which Gly(8) of Pis-1 was replaced with Nlys (Lys peptoid residue). Pis-1[NkG] had higher antibacterial activity and lower cytotoxicity against mammalian cells than Pis-1 and Pis-1[PG]. We determined the tertiary structure of Pis-1[PG] and Pis-1[NkG] in the presence of DPC micelles by NMR spectroscopy. Both peptides had a three-turn helix in the C-terminal region and a bent structure in the center. Pis-1[PG] has a rigid bent structure at Pro(8) whereas Pis-1[NkG] existed as a dynamic equilibrium of two conformers with a flexible hinge structure at Nlys(8). Depolarization of the membrane potential of Staphylococcus aureus and confocal laser-scanning microscopy study revealed that Pis-1[NkG] effectively penetrated the bacterial cell membrane and accumulated in the cytoplasm, whereas Pis-1[PG] did not penetrate the membrane but remained outside or on the cell surface. Introduction of a lysine peptoid at position 8 of Pis-1 provided conformational flexibility and increased the positive charge at the hinge region; both factors facilitated penetration of the bacterial cell membrane and conferred bacterial cell selectivity on Pis-1[NkG].

[Concentrations of blood vitamin A, C, E, coenzyme Q10 and urine cotinine related to cigarette smoking exposure].

BACKGROUND: In smokers, smoking causes many disease entities including cancers, chronic pulmonary diseases and cardiovascular diseases. Passive smoking is also accepted as a carcinogen and its adverse health effects are emphasized. We measured blood vitamin A, C, E (alpha-, beta- and gamma-tocopherol), coenzyme Q10 and urine cotinine concentrations in nonsmokers and smokers. METHODS: Twenty-one healthy nonsmokers and 24 healthy smokers were included in this study. Smoking status was assessed with a self-reported questionnaire. Plasma was analyzed for coenzyme Q10 and serum for vitamin A, C, E using HPLC (Agilent Technologies Inc., USA) and random urine for cotinine using LC/tandem mass spectrometry (Applied Biosystems Inc., Canada). RESULTS: Smokers had significantly lower serum concentrations of vitamin C than nonsmokers (P=0.0005). No significant differences in concentrations of serum vitamin A, E, and plasma coenzyme Q10 were observed. Smokers had highly elevated urine cotinine levels (1,454+/-903 ng/mL). In 16 (76.2%) of 21 nonsmokers, urine cotinine was detected (3.25+/-4.08 ng/mL). The correlations between urine cotinine and blood antioxidants levels were not found. Neither, the correlation between smoking status and blood antioxidants & urine cotinine was found. CONCLUSIONS: This study shows that smokers had significantly lower vitamin C levels among nonenzymatic antioxidants, namely, vitamin A, C, E and coenzyme Q10. High detection rate of urine cotinine in nonsmokers show the seriousness of passive smoking exposure, therefore more social efforts should be directed to reduce passive smoking exposure.

Dynamic thermodynamic resolution: advantage by separation of equilibration and resolution.

In the investigation of a chemical reaction, researchers typically survey variables such as time, temperature, and stoichiometry to optimize yields. This Account demonstrates how control of these variables, often in nontraditional ways, can provide significant improvements in enantiomeric ratios for asymmetric reactions. Dynamic thermodynamic resolution (DTR) offers a convenient method for the resolution of enantiomeric products in the course of a reaction. This process depends on an essential requirement: the equilibration of the penultimate diastereomers must be subject to external control. As a general case, the reaction of A(R), A(S) with B under the influence of the chiral species, L*, gives resolved products C(R) and C(S). In the first step of dynamic resolution under thermodynamic control, the enantiomeric reactants A(R) and A(S) and L* form the diastereomers A(R)/L* and A(S)/L*. The equilibrium between A(R) and A(S) can be rapid, slow, or not operative, and L* can represent a ligand, an auxiliary, or a crystallization process that provides a chiral environment. Second, the populations of the diastereomers are controlled, usually by thermal equilibration. Finally, the reaction of the diastereomers with a reagent B provides the enantiomeric products C(R) and C(S). The control of the diastereomeric equilibrium distinguishes DTR from other resolution techniques. By contrast, physical resolutions separate thermodynamically stable, nonequilibrating diastereomers, and dynamic kinetic resolutions utilize kinetic control for reactions of rapidly equilibrating diastereomers. The dynamic thermodynamic resolutions discussed in this Account illustrate cases of significantly improved enantioselectivities using this technique. Although many of the well-recognized cases come from organolithium chemistry, the principles are general, and we also present cases facilitated by other chemistries. This approach has been used to control enantioselectivities in a number of different reactions, with improvements in enantiomeric ratios up to 99% from essentially racemic reactants.

Regulation of apoptosis by modified naringenin derivatives in human colorectal carcinoma RKO cells.

Flavonoids are micronutrients that are widely detected in foods of plant origin and have been ascribed pharmacological properties. Several biological functions of flavonoids have been thus far identified, whereas there currently exists a lack of evidence to support the relationship between the structure-activity relationship and apoptosis-inducing activity. In an attempt to determine the importance of the OH group or substitution of the 5- or 7-carbon in the diphenylpropane skeleton of flavonoids, we selected 14 different flavonoids with different structures, particularly with regard to the 5- or 7-carbon, and found that naringenin treatment caused a slight decrease in the cell viability of the human colorectal carcinoma RKO cells. Next, in order to characterize the effects of specific substitutions of the 7-carbon of naringenin on apoptosis-regulatory activities, and in an attempt to develop anti-proliferative flavonoid derivatives that would be more effective against colon cancer, we originally synthesized several modified naringenin derivatives (MNDs) including 7-O-benzyl naringenin (KUF-1) and 7-O-(m-metoxybenzyl) naringenin (KUF-2). Treatment with KUF-1 or KUF-2 resulted in significant apoptosis-inducing effects concomitant with losses in mitochondrial membrane potential, caspase activation, intracellular ROS production, and sustained ERK activation. Our data show that KUF-1 or KUF-2 regulate the apoptosis of RKO cells via intracellular ROS production coupled with the concomitant activation of the ERK signaling pathway, thereby implying that hydroxylation or substitution at C7 is critical for the apoptosis-inducing activity of flavonoids.

Induction of apoptotic cell death by synthetic naringenin derivatives in human lung epithelial carcinoma A549 cells.

Although flavonoids, which are both qualitatively and quantitatively one of the largest groups of natural products, exhibit a variety of beneficial health effects, the exact molecular mechanism of the cellular activities is still not fully explained and there currently exists a lack of evidence for any relationship between the structure-activity relationship and apoptosis-inducing activity. In order to determine the importance of the OH group or substitution of the 5 or carbon-7 in the diphenylpropane skeleton of flavonoids, we originally synthesized several modified naringenin derivatives, including 7-O-benzyl naringenin (KUF-1) and 7-O-(MeO-L-Leu-D-Pro-carbonylmethyl) naringenin (KUF-7). Treatment with KUF-1 or KUF-7 resulted in significant apoptosis-inducing effects concomitant with chromatin condensation, caspase activation, and intracellular ROS production. Our data indicate that originally synthesized naringenin derivatives, KUF-1 and KUF-7 differentially regulate the apoptosis of A549 cells via intracellular ROS production coupled with the concomitant activation of the caspase cascade signaling pathway, thereby implying that hydroxylation or substitution at Carbon-7 is critical for the apoptosis-inducing activity of flavonoids.

Human glycine alpha1 receptor inhibition by quercetin is abolished or inversed by alpha267 mutations in transmembrane domain 2.

Quercetin, one of the flavonoids, is a compound of low molecular weight found in fruits and vegetables. Besides its antioxidative effect, quercetin also shows a wide range of diverse neuropharmacological actions. However, the cellular mechanisms of quercetin's actions, especially on ligand-gated ion channels and synaptic transmissions, are not well studied. We investigated the effect of quercetin on the human glycine alpha1 receptor channel expressed in Xenopus oocytes using a two-electrode voltage clamp technique. Application of quercetin reversibly inhibited glycine-induced current (I(Gly)). Quercetin's inhibition depends on its dose, with an IC(50) of 21.5+/-.2 microM. The inhibition was sensitive to membrane voltages. Site-directed mutations of S267 to S267Y but not S267A, S267F, S267G, S267K, S267L and S267T at transmembrane domain 2 (TM2) nearly abolished quercetin-induced inhibition of I(Gly). In contrast, in site-directed mutant receptors such as S267 to S267I, S267R and S267V, quercetin enhanced I(Gly) compared to the wild-type receptor. The EC(50) was 22.6+/-1.4, 25.5+/-4.2, and 14.5+/-3.1 microM for S267I, S267R and S267V, respectively. These results indicate that quercetin might regulate the human glycine alpha(1) receptor via interaction with amino acid residue alpha267 and that alpha267 plays a key role in determining the regulatory consequences of the human glycine alpha1 receptor by quercetin.

Effects of Pro --> peptoid residue substitution on cell selectivity and mechanism of antibacterial action of tritrpticin-amide antimicrobial peptide.

To investigate the effect of Pro --> peptoid residue substitution on cell selectivity and the mechanism of antibacterial action of Pro-containing beta-turn antimicrobial peptides, we synthesized tritrpticin-amide (TP, VRRFPWWWPFLRR-NH(2)) and its peptoid residue-substituted peptides in which two Pro residues at positions 5 and 9 are replaced with Nleu (Leu peptoid residue), Nphe (Phe peptoid residue), or Nlys (Lys peptoid residue). Peptides with Pro --> Nphe (TPf) or Pro --> Nleu substitution (TPl) retained antibacterial activity but had significantly higher toxicity to mammalian cells. In contrast, Pro --> Nlys substitution (TPk) increased the antibacterial activity but decreased the toxicity to mammalian cells. Tryptophan fluorescence studies indicated that the bacterial cell selectivity of TPk is closely correlated with a preferential interaction with negatively charged phospholipids. Interestingly, TPk was much less effective at depolarizing of the membrane potential of Staphylococus aureus and Escherichia coli spheroplasts and causing the leakage of a fluorescent dye entrapped within negatively charged vesicles. Furthermore, confocal laser-scanning microscopy showed that TPk effectively penetrated the membrane of both E. coli and S. aureus and accumulated in the cytoplasm, whereas TP and TPf did not penetrate the cell membrane but remained outside or on the cell membrane. These results suggest that the bactericidal action of TPk is due to inhibition of the intracellular components after penetration of the bacterial cell membrane. In addition, TPK with Lys substitution effectively depolarized the membrane potential of S. aureus and E. coli spheroplasts. TPK induced rapid and effective dye leakage from bacterial membrane-mimicking liposomes and did not penetrate the bacterial cell membranes. These results suggested that the ability of TPk to penetrate the bacterial cell membranes appears to involve the dual effects that are related to the increase in the positive charge and the peptide's backbone change by peptoid residue substitution. Collectively, our results showed that Pro --> Nlys substitution in Pro-containing beta-turn antimicrobial peptides is a promising strategy for the design of new short bacterial cell-selective antimicrobial peptides with intracellular mechanisms of action.