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Chem Pharm Bull [journal]
- Thotneosides A, B and C: Potent Antioxidants from Nepalese Crude Drug, Leaves of Aconogonon molle. [JOURNAL ARTICLE]
- Chem Pharm Bull (Tokyo) 2013 Nov 30.
Three new glycosides: thotneoside A (quercetin 3-O-(6"-O-phenylacetyl)-β-D-galactopyranoside) (1), thotneoside B (quercetin 3-O-(6"-O-phenylacetyl)-β-D-glucopyranoside) (2) and thotneoside C (3-methyl-2-butenoic acid 1-O-b-D-glucopyranoside) (3), together with nine known compounds; quercetin (4), quercetin 3-O-b-D-galactopyranoside (5), quercetin 3-O-(6"-O-galloyl)-β-D-galactopyranoside (6), quercetin 3-O-β-D-galacturonopyranoside (7), quercetin 3-O-β-D-glucuronopyranoside (8), quercetin 3-O-α-L-rhamnopyranoside (9), rutin (10), quercetin 3-O-α-L-arabinopyranoside (11) and 2,4,6-trihydroxyacetophenone 2-O-β-D-glucopyranoside (12) have been isolated from the shade dried leaves of Aconogonon molle, commonly known as "Thotne" in Nepal. The structures were elucidated on the basis of chemical and spectroscopic methods. All of these compounds were isolated for the first time from A. molle and their in vitro antioxidant activity was evaluated by DPPH free radical scavenging assay. Quercetin (4) and its glycosides (1-2, 5-11) showed significant free radical scavenging activity.
- Facile preparation of dehydrodigallic Acid and its derivative for the synthesis of ellagitannins. [Journal Article]
- Chem Pharm Bull (Tokyo) 2013; 61(12):1308-14.
A facile method for the synthesis of dehydrodigallic acid, which is a fundamental structure of ellagitannins, was developed. A classical Ullmann condition was effective for the formation of the highly hindered biaryl ether structure, and we clarified that the suitable protection of the phenolic hydroxy groups was crucial in this reaction. In this way, the synthesis of dehydrodigallic acid and its derivative was successfully performed. The described method would provide a synthetic utility toward ellagitannins.
- Synthesis and Antioxidant Activity of Styrylsulfonylmethyl 1,3,4-Oxadiazoles, Pyrazolyl/Isoxazolyl-1,3,4-oxadiazoles. [Journal Article]
- Chem Pharm Bull (Tokyo) 2013; 61(12):1291-7.
A new class of mono and bis heterocycles-styrylsulfonylmethyl 1,3,4-oxadiazoles, pyrazolyl/isoxazolyl-1,3,4-oxadiazoles were prepared and studied their antioxidant activity. The compound methyl substituted 2-(p-methylphenylamino-sulfonylmethyl)-5-[Z-(p-methylstyrylsulfonylmethyl)]-1,3,4-oxadiazole displayed slightly higher antioxidant activity than the standard ascorbic acid.
- Iontophoretic Transdermal Delivery of Glycyrrhizin: Effects of pH, Drug Concentration, Co-ions, Current Intensity, and Chemical Enhancers. [Journal Article]
- Chem Pharm Bull (Tokyo) 2013; 61(12):1275-81.
The aim of the present study was to evaluate the feasibility of transdermal delivery of glycyrrhizin, an agent used in the treatment of chronic hepatitis C, by cathodal iontophoresis using Ag/AgCl electrodes in vitro. The effects of donor pH (pH 4-7), concentration of drug (0.025-0.2% (w/v)), concentration of external chloride ions (Cl(-)) (0-133 mM), current strength (0-0.5 mA/cm(2)), and permeation enhancers (urea and Tween 80) on the skin permeability of glycyrrhizin were examined in in vitro skin permeation studies using porcine ear skin as the membrane. The cumulative amount of permeated glycyrrhizin and the steady-state skin permeation flux of glycyrrhizin across porcine skin increased in a pH-dependent manner. The skin permeability of glycyrrhizin was independent of the concentration of drug and competed only with a high external Cl(-) concentration. The skin permeation flux of glycyrrhizin increased with the current (R(2)=0.8955). The combination of iontophoresis and enhancers provided an additive or synergistic effect, and a skin permeation flux of about 60 µg/h/cm(2) was achieved. The plasma concentration of glycyrrhizin in humans, extrapolated from the in vitro steady-state permeation flux across porcine skin, was within the therapeutic level. These results suggest that cathodal iontophoresis can be used as a transdermal drug delivery system for glycyrrhizin using reasonable patch sizes and acceptable levels of current intensity.
- Determination of selected nitropolycyclic aromatic hydrocarbons in water samples. [Journal Article]
- Chem Pharm Bull (Tokyo) 2013; 61(12):1269-74.
A new method for the analysis of selected nitropolycyclic aromatic hydrocarbons (NPAHs) at ultra-trace levels in water samples is proposed. Particulate NPAHs were collected on a GC glass fiber filter. Soluble NPAHs were collected on a C18 Empore disk. After simple clean-up and concentration of NPAHs in both phases, the NPAHs were analyzed using HPLC equipped with clean-up, reducer, concentration and chemiluminescence detection units. The proposed method showed good linear calibration curves with correlation coefficients (r(2)) ranging from 0.9954 to 0.9998. The limits of detection ranged from 0.013 to 0.15 nmol/L (soluble NPAHs) and from 0.01 to 0.13 nmol/L (particulate NPAHs) for 5 NPAHs [(9-nitroanthracene, 1-nitropyrene, 6-nitrochrysene (6-NC), 7-nitrobenz[a]anthracene and 6-nitrobenzo[a]pyrene] having 3 to 5 rings analyzed, when 1.5 L of water sample was used. The repeatability for soluble NPAHs ranged between 4.2 and 6.8% (n=5), while for particulate NPAHs, it varied between 2.2 and 2.8% (n=5). The proposed method successfully determined the above NPAHs expect 6-NC in river water samples, suggesting that this method is suitable for the ultra-trace analysis of NPAHs in water samples.
- Synthesis and Structure-Activity Relationships of Novel Zwitterionic Compounds as Peroxisome Proliferator Activated Receptor α/γ Dual Agonists with Improved Physicochemical Properties. [Journal Article]
- Chem Pharm Bull (Tokyo) 2013; 61(12):1248-63.
We describe herein the design, syntheses and structure-activity relationships (SAR) of novel zwitterionic compounds as non-thiazolidinedion (TZD) based peroxisome proliferator activated receptor (PPAR) α/γ dual agonists. In the previous report, we obtained compound 1 showing potent PPARα/γ dual agonistic activities, together with a great glucose lowering effect in the db/db mice. However, this compound possessed fatal issues such as potent cytochrome P450 (CYP)3A4 direct inhibitory activity. Thus, we carried out the medicinal optimization to improve these while maintaining the potent PPAR agonistic activity. As a result, the issues were addressed by changing the furan ring to a low lipophilic 1,3,4-oxadiazole ring. Additionally, these oxadiazole derivatives exhibited a significant decrease in plasma glucose and plasma triglyceride levels without marked weight gain.
- Synthesis and Structure-Activity Relationship of Naphtho[1,2-b]furan-2-carboxamide Derivatives as Melanin Concentrating Hormone Receptor 1 Antagonists. [Journal Article]
- Chem Pharm Bull (Tokyo) 2013; 61(12):1239-47.
The discovery that novel naphtho[1,2-b]furan-2-carboxamides containing linked piperidinylphenylacetamide groups serve as melanin concentrating hormone receptor 1 (MCH-R1) antagonists is described. An extensive structure-activity relationship (SAR) study, probing members of this family that contain a variety of aryl and heteroaryl groups at C-5 of the naphtho[1,2-b]furan-2-carboxamide skeleton and having different chain linker lengths, led to the identification of the 5-(4-pyridinyl) substituted analog 10b as a highly potent MCH-R1 antagonist with an IC50 value of 3 nM. This substance also displays good metabolic stability and it does not significantly inhibit cytochrome P450 (CYP450) enzymes. However, 10b has unacceptable oral bioavailability.
- Impact of physicochemical profiling for rational approach on drug discovery. [Journal Article]
- Chem Pharm Bull (Tokyo) 2013; 61(12):1228-38.
Solid-state characterization plays a vital role in lead optimization and candidate selection with the appropriate physicochemical properties for proper oral dosage formulation. Aqueous solubility is an important parameter in the successful development of oral dosage formulation since poor aqueous solubility limits absorption. In this study, we summarized an efficient approach using a small amount of sample for solid-state characterization, including thermodynamic solubility, which is defined as physicochemical profiling. By using the physicochemical profiling results of 75 anti-cancer drugs and clinical candidates, we examined the relationship between thermodynamic solubility and molecular structural parameters and assessed the effects of thermodynamic solubility on pharmacokinetic profile for rational soluble drug design. The Log DpH 7.4, aromatic ring count, and hydrogen bond count were good indicators for predicting sparingly soluble compounds that increase the lattice energy because of π-π stacking and hydrogen bonds, resulting in lowered thermodynamic solubility. The level of thermodynamic solubility in simulated intestinal fluid (pH 6.8) in the presence and absence of bile acid, which is required for minimal acceptable bioavailability (>30%), was 1 µg/mL and 10 µg/mL, respectively. Physicochemical profiling, which includes thermodynamic solubility considering its solid-state properties, contributes to rational lead optimization and efficient candidate selection for drug development.
- Continuous wavelet transforms for the simultaneous quantitative analysis and dissolution testing of Lamivudine-Zidovudine tablets. [Journal Article]
- Chem Pharm Bull (Tokyo) 2013; 61(12):1220-7.
Dissolution testing has a very vital importance for a quality control test and prediction of the in vivo behavior of the oral dosage formulation. This requires the use of a powerful analytical method to get reliable, accurate and precise results for the dissolution experiments. In this context, new signal processing approaches, continuous wavelet transforms (CWTs) were improved for the simultaneous quantitative estimation and dissolution testing of lamivudine (LAM) and zidovudine (ZID) in a tablet dosage form. The CWT approaches are based on the application of the continuous wavelet functions to the absorption spectra-data vectors of LAM and ZID in the wavelet domain. After applying many wavelet functions, the families consisting of Mexican hat wavelet with the scaling factor a=256, Symlets wavelet with the scaling factor a=512 and the order of 5 and Daubechies wavelet at the scale factor a=450 and the order of 10 were found to be suitable for the quantitative determination of the mentioned drugs. These wavelet applications were named as mexh-CWT, sym5-CWT and db10-CWT methods. Calibration graphs for LAM and ZID in the working range of 2.0-50.0 µg/mL and 2.0-60.0 µg/mL were obtained measuring the mexh-CWT, sym5-CWT and db10-CWT amplitudes at the wavelength points corresponding to zero crossing points. The validity and applicability of the improved mexh-CWT, sym5-CWT and db10-CWT approaches was carried out by the analysis of the synthetic mixtures containing the analyzed drugs. Simultaneous determination of LAM and ZID in tablets was accomplished by the proposed CWT methods and their dissolution profiles were graphically explored.
- Quantum chemical study for radical-induced DNA effects and damage. [Journal Article]
- Chem Pharm Bull (Tokyo) 2013; 61(12):1214-9.
Differences in molecular interaction between bases (adenine (A), guanine (G), and cytosine (C)) and the methyl (Me)-radical were investigated by perturbation analysis using the quantum chemical method. Part of the source of damage to the DNA was elucidated at the molecular level. In the reaction of each of the saccharide derivatives (dA, dG, and dC) with Me-radical, the reactivity of dG (≈dA) is more than about 10 times larger than that of dC. Therefore, it is expected that the base G (and A) was more than about 10 times than the base C in radical-reactivity of the base. For the reaction of dA and dG with the radical, the C(8) site of the partial purine ring of dA and dG, and the C(5) site of the pyrimidine ring of dC were the main reaction sites for methylation. In the reaction of DNA composed of hydrogen-bonded base pairs G-C and A-T with the radical, the purine ring in the constituent base G reacted preferentially with the radical to yield 8-methyl-guanines.