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71.
Chalermpong Saenjum Thanawat Pattananandecha Kouichi Nakagawa 《Molecules (Basel, Switzerland)》2021,26(12)
In this study, we investigated the antioxidant and anti-inflammatory phytochemicals and paramagnetic species in dragon fruit using high-performance liquid chromatography (HPLC) and electron paramagnetic resonance (EPR). HPLC analysis demonstrated that dragon fruit is enriched with bioactive phytochemicals, with significant variations between each part of the fruit. Anthocyanins namely, cyanidin 3-glucoside, delphinidin 3-glucoside, and pelargonidin 3-glucoside were detected in the dragon fruit peel and fresh red pulp. Epicatechin gallate, epigallocatechin, caffeine, and gallic acid were found in the dragon fruit seed. Additionally, 25–100 mg × L−1 of dragon fruit pulp and peel extracts containing enrichment of cyanidin 3-glucoside were found to inhibit the production of reactive oxygen species (ROS), reactive nitrogen species (RNS), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) in cell-based studies without exerted cytotoxicity. EPR primarily detected two paramagnetic species in the red samples. These two different radical species were assigned as stable radicals and Mn2+ (paramagnetic species) based on the g-values and hyperfine components. In addition, the broad EPR line width of the white peel can be correlated to a unique moiety in dragon fruit. Our EPR and HPLC results provide new insight regarding the phytochemicals and related stable intermediates found in various parts of dragon fruit. Thus, we suggest here that there is the potential to use dragon fruit peel, which contains anthocyanins, as a natural active pharmaceutical ingredient. 相似文献
72.
NMR and DFT studies on persistent carbocations derived from benzo[kl]xanthene,dibenzo[d,d′]benzo[1,2‐b:4,3‐b′]difuran,and dibenzo[d,d′]benzo[1,2‐b:4,5‐b′]difuran in superacidic media 下载免费PDF全文
Takao Okazaki Madoka Nakagawa Takeshi Futemma Toshikazu Kitagawa 《Journal of Physical Organic Chemistry》2016,29(2):107-111
Persistent carbocations generated by the protonation of hetero‐polycyclic aromatic compounds with oxygen atom(s) were studied by experimental NMR and density function theory calculations. Benzo[kl]xanthene ( 1 ), dibenzo[d,d′]benzo[1,2‐b:4,3‐b′]difuran ( 2 ), and dibenzo[d,d′]benzo[1,2‐b:4,5‐b′]difuran ( 3 ) were synthesized by the annulation of arenediazonium salts. Compound 1 in FSO3H‐SbF5 (4:1)/SO2ClF and 3 in FSO3H‐SbF5 (1:1)/SO2ClF ionized to 1aH+ with protonation at C(4) and to 3aH+ with protonation at C(6), and these cations were successfully observed by NMR at low temperatures. The density function theory calculations indicated that 1aH+ and 3aH+ were the most stable protonated carbocations and that 2 should ionize to 2aH+ with protonation at C(6). According to the changes in 13C chemical shifts (Δδ13C), the positive charge was delocalized into the naphthalene unit for 1aH+ , into one benzo[b,d]furan unit for 2aH+ , and into one benzo[b,d]furan unit for 3aH+ . Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
73.
Small-angle x-ray scattering and dielectric spectroscopy investigation on the solutions of recombinant human serum albumin and its heme hybrid revealed that heme incorporation induces a specific long-range attractive potential between protein molecules. This is evidenced by the enhanced forward intensity upon heme binding, despite no hindrance to rotatory Brownian motion, unbiased colloid osmotic pressure, and discontiguous nearest-neighbor distance, confirming monodispersity of the proteins. The heme-induced potential may play a trigger role in recognition of the ligand-filled human serum albumins in the circulatory system. 相似文献
74.
Dr. Yuki Kishimoto Dr. Osamu Nakagawa Akane Fujii Dr. Kotaro Yoshioka Dr. Tetsuya Nagata Prof. Dr. Takanori Yokota Prof. Dr. Yoshiyuki Hari Prof. Dr. Satoshi Obika 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(7):2427-2438
Artificial nucleic acids are widely used in various technologies, such as nucleic acid therapeutics and DNA nanotechnologies requiring excellent duplex-forming abilities and enhanced nuclease resistance. 2′-O,4′-C-Methylene-bridged nucleic acid/locked nucleic acid (2′,4′-BNA/LNA) with 1,3-diaza-2-oxophenoxazine (BNAP ( BH )) was previously reported. Herein, a novel BH analogue, 2′,4′-BNA/LNA with 9-(2-aminoethoxy)-1,3-diaza-2-oxophenoxazine (G-clamp), named BNAP-AEO ( BAEO ), was designed. The BAEO nucleoside was successfully synthesized and incorporated into oligodeoxynucleotides (ODNs). ODNs containing BAEO possessed up to 104-, 152-, and 11-fold higher binding affinities for complementary (c) RNA than those of ODNs containing 2′-deoxycytidine ( C ), 2′,4′-BNA/LNA with 5-methylcytosine ( L ), or 2′-deoxyribonucleoside with G-clamp ( PAEO ), respectively. Moreover, duplexes formed by ODN bearing BAEO with cDNA and cRNA were thermally stable, even under molecular crowding conditions induced by the addition of polyethylene glycol. Furthermore, ODN bearing BAEO was more resistant to 3′-exonuclease than ODNs with phosphorothioate linkages. 相似文献
75.
76.
Quantitative Detection for Porphyromonas gingivalis in Tooth Pocket and Saliva by Portable Electrochemical DNA Sensor Linked with PCR 下载免费PDF全文
Keiichiro Yamanaka Shinichi Sekine Takahiro Uenoyama Masahiro Wada Tomohiko Ikeuchi Masato Saito Yoshinori Yamaguchi Eiichi Tamiya 《Electroanalysis》2014,26(12):2686-2692
Here, a quantitative electrochemical analysis of periodontal bacteria in gingival crevicular fluid (GCF) and saliva by direct polymerase chain reaction (PCR) is presented. The electrochemical measurement was performed by mixing with PCR products and electrochemical indicator (bisbenzimidazole trihydrochloride). The peak current of indicator is reduced due to slower diffusion when the dye intercalates into the amplified DNA, and the degree of reduction in the peak current is correlates with the quantity of amplified DNA. Therefore, a quantitative analysis is possible by using our electrochemical method at the end point of PCR. In the GCF testing, The number of Porphyromonas gingivalis (Pg) detected by our electrochemical method at the end point of PCR were almost same compared with that were calculated by the conventional method of quantitative real? time PCR. In the saliva testing, the relationship between number of Pg in saliva and average pocket depth, and age‐dependence were also clearly observed. Since the saliva sample is obtained in a non‐invasive manner, this method is useful for the primary screening of periodontal disease. Moreover, our detection method is simple and uses a hand‐held potentiostat making it suitable for development of an on‐site periodontal diagnosis system. 相似文献
77.
Takayuki Suzuki Tomohiko Kitsukawa Yasushi Hirata Satomi Tanaka Naoya Iwasaki 《先进技术聚合物》2014,25(1):123-129
The copolymer of hydroxypropyl methacrylate (HPMA) and photochromic spiropyran methacrylate (SPMA) has been synthesized. The films of the copolymer (P(HPMA‐SPMA)) in a hydrated state showed reversible swelling–shrinking behavior in response to photoreversible isomerization and metal complexation of SPMA units in spite of covalently noncross‐linked copolymers. In addition, the protonated open form of the SPMA units of the copolymer was possibly stabilized thermodynamically by the HPMA units from ultraviolet–visible absorption measurement of the hydrated P(HPMA‐SPMA) film. On the other hand, the difference in color of the hydrated films between P(HPMA‐AABMA) and P(NIPMA‐AABMA), which was a copolymer of N‐isopropyl methacryl amide (NIPMA) and azobenzene methacrylate (AABMA) as a pH indicator, was suggestive of the interference of the proximal hydroxyl groups of the immobilized HPMA units with protonation of the AABMA units. The HPMA units of the copolymers also contributed to improvement of thermodynamic stability of the metal complexes with the SPMA units. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
78.
Design of Ratiometric Fluorescent Probes Based on Arene–Metal‐Ion Interactions and Their Application to CdII and Hydrogen Sulfide Imaging in Living Cells 下载免费PDF全文
Ippei Takashima Miyuki Kinoshita Ryosuke Kawagoe Saika Nakagawa Prof. Dr. Manabu Sugimoto Prof. Dr. Itaru Hamachi Prof. Dr. Akio Ojida 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(8):2184-2192
Non‐coordinative interactions between a metal ion and the aromatic ring of a fluorophore can act as a versatile sensing mechanism for the detection of metal ions with a large emission change of fluorophores. We report the design of fluorescent probes based on arene–metal‐ion interactions and their biological applications. This study found that various probes having different fluorophores and metal binding units displayed significant emission redshift upon complexation with metal ions, such as AgI, CdII, HgII, and PbII. X‐ray crystallography of the complexes confirmed that the metal ions were held in close proximity to the fluorophore to form an arene–metal‐ion interaction. Electronic structure calculations based on TDDFT offered a theoretical basis for the sensing mechanism, thus showing that metal ions electrostatically modulate the energy levels of the molecular orbitals of the fluorophore. A fluorescent probe was successfully applied to the ratiometric detection of the uptake of CdII ions and hydrogen sulfide (H2S) in living cells. These results highlight the utility of interactions between arene groups and metal ions in biological analyses. 相似文献
79.
Koji Takagi Tsuyoshi Nakagawa Hidenobu Takao 《Journal of polymer science. Part A, Polymer chemistry》2010,48(1):91-98
Two arylenevinylene compounds bearing the cyano group at α‐position ( 6 ) and β‐position ( 9 ) from the dialkoxylphenylene unit were synthesized, in which the molecular termini were functionalized with 3‐bromocarbazole. The Suzuki coupling copolymerization of these compounds with 1,4‐bis[(3′‐bromocarbazole‐9′‐yl)methylene]‐2,5‐didecyloxybenzene and 9,9‐dihexylfluorene‐2,7‐bis(boronic acid) was carried out to obtain copolymers ( cp67 and cp97 ) containing the cyano‐substituted arylenevinylene fluorophore of 7 mol %. Model compounds ( 6 ′ and 9 ′) corresponding to the arylenevinylene fluorophore were also prepared. The UV spectra of copolymers resembled that of homopolymer hp with no arylenevinylene segment in both CHCl3 solution and thin film. The emission maxima of copolymers in CHCl3 (394 nm) agreed with that of homopolymer indicating that the emission bands originated from the carbazole‐fluorene‐carbazole segment. The emission maximum wavelength of copolymer cp67 in thin film (477 nm) indicated fluorescence from the cyano‐substituted arylenevinylene fluorophore because of the occurrence of fluorescence resonance electron transfer. In contrast, copolymer cp97 showed fluorescence at 528 nm to suggest the formation of a new emissive species such as a charge‐transfer complex (exciplex). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 91–98, 2010 相似文献
80.
Yoshiyuki Koyano Norio Takenaka Yukinori Nakagawa Masataka Nagaoka 《Journal of computational chemistry》2010,31(14):2628-2641