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101.
Tran Van Chien Nguyen The Anh Nguyen Tuan Thanh Tran Thi Phuong Thao Tran Van Loc Tran Van Sung 《Natural product research》2019,33(2):212-218
Two new prenylisoflavones, 3′,4′,5-trihydroxy-8-prenyl-dihydrofuran[2″,3″:7,6]isoflavone (1) and 4′,5-dihydroxy-8-prenyl-dihydrofuran[2″,3″:7,6]isoflavone (2), along with five known prenylisoflavones (3–7), benzylalcohol-4-O-β-d-glucoside (8) and two cinnamic acid esters (9, 10) were isolated from the leaves of Maclura cochinchinensis (Cudrania cochinchinensis). Their structures were elucidated by analysis of NMR (1H-, 13C-NMR, HSQC, HMBC), MS spectra and comparison with the published data. Compounds 4–10 were the first time isolated from this species. Prenylisoflavones 1–4 and 6–7 were evaluated for their in vitro cytotoxic activity on KB and HepG2 cancer cell lines. Compound 4 showed cytotoxic activity against both cancer cell lines with IC50 values of 26.99 and 19.95 μM, respectively. The other compounds were considered as inactive. 相似文献
102.
Le PM Martin MT Van Hung N Guénard D Sévenet T Platzer N 《Magnetic resonance in chemistry : MRC》2005,43(4):283-293
Extracts of fruits and leaves of Connarus paniculatus afford six quinolizidine alkaloids which were identified as piptanthine, 18-epipiptanthine, ormosanine, homoormosanine, podopetaline (monohydrochloride) and homopodopetaline on the basis of high-field NMR studies. 1D and 2D NMR experiments provide complete assignments of the (1)H and (13)C spectra. In conjunction with detection of nuclear Overhauser effects (NOESY), these results allow detailed structure characterization including determination of relative configurations for the chiral sites and conformational analysis. Exchange phenomena involving nitrogen inversion were detected. 相似文献
103.
A continuum of solutions in a Fréchet space of a nonlinear functional integral equation in N variables 下载免费PDF全文
In this paper, we investigate the set of solutions of a nonlinear functional integral equation in N variables in a Fréchet space. Applying a fixed point theorem of Krasnosel'skii type and a structure theorem of Krasnosel'skii and Perov, a sufficient condition is established such that the set of solutions is a continuum, that is, nonempty, compact and connected. Furthermore, based on Aronszajn type results and a theorem proved by Vidossich, we show that this solutions set is also a compact . This is also true with solutions set of a nonlinear Volterra–Hammerstein integral equation. 相似文献
104.
Immobilization of the Gas Signaling Molecule H2S by Radioisotopes: Detection,Quantification, and In Vivo Imaging 下载免费PDF全文
Woonghee Lee Min Hwan Kim Phuong Tu Huynh Heesu Ahn Dr. Nikunj Bhatt Dr. Yong Jin Lee Dr. Jung Young Kim Prof. Kwon Moo Park Prof. Isao Ishii Prof. Shin‐Geol Kang Prof. Jeongsoo Yoo 《Angewandte Chemie (International ed. in English)》2016,55(32):9365-9370
Hydrogen sulfide (H2S) has multifunctional roles as a gas signaling molecule in living systems. However, the efficient detection and imaging of H2S in live animals is very challenging. Herein, we report the first radioisotope‐based immobilization technique for the detection, quantification, and in vivo imaging of endogenous H2S. Macrocyclic 64Cu complexes that instantly reacted with gaseous H2S to form insoluble 64CuS in a highly sensitive and selective manner were prepared. The H2S concentration in biological samples was measured by a thin‐layer radiochromatography method. When 64Cu–cyclen was injected into mice, an elevated H2S concentration in the inflamed paw was clearly visualized and quantified by Cerenkov luminescence and positron emission tomography (PET) imaging. PET imaging was also able to pinpoint increased H2S levels in a millimeter‐sized infarcted lesion of the rat heart. 相似文献
105.
In this paper we consider a nonlinear Love equation associated with Dirichlet conditions. First, under suitable conditions, the existence of a unique local weak solution is proved. Next, a blow up result for solutions with negative initial energy is also established. Finally, a sufficient condition guaranteeing the global existence and exponential decay of weak solutions is given. The proofs are based on the linearization method, the Galerkin method associated with a priori estimates, weak convergence, compactness techniques and the construction of a suitable Lyapunov functional. To our knowledge, there has been no decay or blow up result for equations of Love waves or Love type waves before. 相似文献
106.
Jang J Na M Thuong PT Njamen D Mbafor JT Fomum ZT Woo ER Oh WK 《Chemical & pharmaceutical bulletin》2008,56(1):85-88
Phytochemical study on an EtOAc-soluble extract of the root bark of Erythrina mildbraedii resulted in the isolation of six prenylated flavonoids 1-6. Based on physicochemical and spectroscopic analyses, their structures were determined to be new natural products licoflavanone-4'-O-methyl ether (1), 2',7-dihydroxy-4'-methoxy-5'-(3-methylbut-2-enyl)isoflavone (2), and (3R)-2',7-dihydroxy-3'-(3-methylbut-2-enyl)-2',2'-dimethylpyrano[5',6' :4',5']isoflavan (3), along with three known compounds erythrinin B (4), abyssinin II (5), and parvisoflavone B (6). All the isolates, except for compound 4, inhibited PTP1B activity in vitro with IC(50) values ranging from 5.3 to 42.6 microM. This result further suggests that the prenyl group on the B ring of flavonoids plays an important role in suppressing the enzyme PTP1B. 相似文献
107.
Dang Ngoc Quang Tran Cong So Nguyen Thi Phuong Thanh Le Thi Phuong Hoa Pham Huu Dien Truong Minh Luong 《Natural product research》2018,32(7):767-772
A new chalcone named as balanochalcone (1) together with eight known compounds, methyl caffeate (2), β-hydroxydihydrochalcone (3), methyl gallate (4), dimethyl-6,9,10-trihydroxybenzo[kl]xanthene-1,2-dicarboxylate (5), p-coumaric acid (6), quercetin (7), scopoletin (8) and pinoresinol (9) have been isolated from the ethyl acetate extract of Vietnamese Balanophora laxiflora Hemsl. Their structures were characterised by IR, UV, HR-ESI-MS, 1D and 2D NMR and CD spectroscopies. Compounds 2 and 5 showed moderate cytotoxicity against four cancer cell lines, KB (a human epidermal carcinoma), MCF7 (human breast carcinoma), SK-LU-1 (human lung carcinoma) and HepG2 (hepatocellular carcinoma). In addition, compounds 1 and 5 showed moderate antioxidant activity. 相似文献
108.
Nguyen Van Bon Wang San-Lang Nguyen Anh Dzung Vo Thi Phuong Khanh Zhang Li-Jie Nguyen Quang Vinh Kuo Yao-Haur 《Research on Chemical Intermediates》2018,44(2):1411-1424
Research on Chemical Intermediates - Euonymus laxiflorus Champ. (ELC) has been reported to possess potential antidiabetic activity. The aim of this study is to isolate and identify the active... 相似文献
109.
Catalina Biglione Thi Mai Phuong Neumann-Tran Sidra Kanwal Daniel Klinger 《Journal of polymer science. Part A, Polymer chemistry》2021,59(22):2665-2703
Polymeric micro- and nanogels are defined by their water-swollen hydrophilic networks that can often impart outstanding biocompatibility and high-colloidal stability. Unfortunately, this highly hydrophilic nature limits their potential in areas where hydrophobic or amphiphilic interactions are required, for example, the delivery of hydrophobic cargoes or tailored interactions with amphipathic (bio-)surfaces. To overcome this limitation, amphiphilic micro−/nanogels are emerging as new colloidal materials that combine properties from hydrogel networks with hydrophobic segments, known from solid hydrophobic polymer particles or micellar cores. The ability to accurately adjust the balance of hydrophobic and hydrophilic components in such amphiphilic colloidal systems enables new tailored properties. This opens up new applications ranging from the controlled and sustained delivery of hydrophobic drugs, over carriers for catalytic moieties, to their assembly at hydrophilic/hydrophobic interfaces, for example, as advanced stabilizers in Pickering emulsions. While promising, the synthetic realization of such amphiphilic materials remains challenging since hydrophobic and hydrophilic moieties need to be combined in a single colloidal system. As a result, adjusting the micro−/nanogel amphiphilicity often changes the colloidal features too. To overcome these limitations, various strategies have been reported. The aim of this review is to give a brief overview of important synthetic tools, considering both advantages and disadvantages, thus critically evaluating their potential in different research fields. 相似文献
110.
Triphenylamine–Thienothiophene Organic Charge‐Transport Molecular Materials: Effect of Substitution Pattern on their Thermal,Photoelectrochemical, and Photovoltaic Properties 下载免费PDF全文
Thi Huong Le Dr. Quang‐Duy Dao Dr. Mai‐Phuong Nghiêm Prof. Sébastien Péralta Dr. Regis Guillot Prof. Quoc Nghi Pham Prof. Akihiko Fujii Prof. Masanori Ozaki Prof. Fabrice Goubard Prof. Thanh‐Tuân Bui 《化学:亚洲杂志》2018,13(10):1302-1311
Two readily accessible thienothiophene–triphenylamine charge‐transport materials have been synthesized by simply varying the substitution pattern of the triphenylamine groups on a central thienothiophene π‐linker. The impact of the substitution pattern on the thermal, photoelectrochemical, and photovoltaic properties of these materials was evaluated and, based on theoretical and experimental studies, we found that the isomer in which the triphenylamine groups were located at the 2,5‐positions of the thienothiophene core ( TT‐2,5‐TPA ) had better π‐conjugation than the 3,6‐isomer ( TT‐3,6‐TPA ). Whilst the thermal, morphological, and hydrophobic properties of the two materials were similar, their optoelectrochemical and photovoltaic properties were noticeably impacted. When applied as hole‐transport materials in hybrid perovskite solar cells, the 2,5‐isomer exhibited a power‐conversion efficiency of 13.6 %, much higher than that of its 3,6‐counterpart (0.7 %) under the same standard conditions. 相似文献