The Synthesis of Kanamycin Analogs I. α-D-Glucopyranosyl Derivatives of Deoxystreptamine

1973 ◽  
Vol 51 (1) ◽  
pp. 53-66 ◽  
Author(s):  
R. U. Lemieux ◽  
T. L. Nagabhushan ◽  
K. J. Clemetson ◽  
L. C. N. Tucker
Keyword(s):  
Conformational Change ◽  
Ph Change ◽  
Synthetic Compounds ◽  
Effects Of Ph ◽  
Derivatives Of

The procedure developed in this laboratory for the synthesis of α-D-glucopyranosides based on the reaction of dimeric tri-O-acetyl-2-deoxy-2-nitroso-α-D-glucopyranosyl chloride with alcohols was employed to synthesize the three α-D-glucopyranosyl deoxystreptamines and 4,6-di-O-α-D-glucopyranosyl deoxystreptamine. Effects of pH change on the n.m.r. spectra of kanamycins A and B and of the above synthetic compounds are interpreted in terms of a conformational change.

scholarly journals A REVIEW ON ANTI-INFLAMMATORY POTENTIAL OF SUBSTITUTED PYRAZOLINE DERIVATIVES SYNTHESISED FROM CHALCONES

2018 ◽  
Vol 10 (2) ◽  
pp. 9 ◽  
Author(s):  
Muralidharan V. ◽  
Asha Deepti C. ◽  
Raja S.
Keyword(s):  
Inflammatory Activity ◽  
Biological Behaviour ◽  
Synthetic Compounds ◽  
Pyrazoline Ring ◽  
Heterocyclic Derivatives ◽  
Anti Inflammatory ◽  
Novel Drug ◽  
Derivatives Of ◽  
Aromatic Heterocyclic ◽  
Significant Class

The pyrazoline ring is a ubiquitous structural feature of many natural and synthetic compounds with potent anti-inflammatory activity. The creation of novel pyrazoline derivatives and examination of their chemical and biological behaviour have gained additional focus in the current decade. Pyrazolines and its fused heterocyclic derivatives tested with anti-inflammatory activity constitute a significant class of compounds for novel drug evolution. Pyrazoline nucleus when linked with different substituents like alkyl, aromatic, heterocyclic rings and many other groups at different positions on the ring shows considerable to more effective anti-inflammatory activity. This article presents a comprehensive review of the anti-inflammatory activity of some novel derivatives of pyrazoline ring.

Halimium halimifolium: From the Chemical and Functional Characterization to a Nutraceutical Ingredient Design

Planta Medica ◽  
2019 ◽  
Vol 85 (11/12) ◽  
pp. 1024-1033 ◽  
Author(s):  
Khawla Kerbab ◽  
Francesca Sansone ◽  
Lahcene Zaiter ◽  
Tiziana Esposito ◽  
Rita Celano ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Folk Medicine ◽  
Oral Intake ◽  
In Vitro Dissolution ◽  
Bioactive Components ◽  
Ph Change ◽  
Laser Scattering ◽  
Aerial Parts ◽  
Derivatives Of

Abstract Halimium halimifolium (Hh) is a shrub used in Algerian folk medicine to treat gastrointestinal pain. An UHPLC-PDA-ESI/MSn method was developed to identify the metabolic profile of the traditionally used infusion (Hh-A) from the aerial parts. The structures of flavanols were confirmed by NMR analysis after the isolation procedure from a hydrohalcolic extract (Hh-B) that also allowed for the identification of phenolic acids, an aryl butanol glucoside, and different derivatives of quercetin, myricetin, and kaempferol. Tiliroside isomers were the chemical markers of Hh-A and Hh-B (54.33 and 36.00 mg/g, respectively). Hh-A showed a significant scavenging activity both against the radicals 1,1-diphenyl-2-picrylhydrazyl and 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (EC50 = 10.49 µg/mL and TEAC value = 1.98 mM Trolox/mg infusion) and the lipopolysaccharide-induced reactive oxygen species release in A375 and HeLa cells. Moreover, the antihyperglycemic properties, by inhibiting the α-amylase and α-glucosidase enzymes (IC50 = 0.82 mg/mL and 25.01 µg/mL, respectively), were demonstrated. To upgrade the therapeutic effect, a microencapsulation process is proposed as a strategy to optimize stability, handling, and delivery of bioactive components, avoiding the degradation and loss of the biological efficacy after oral intake. Hh-loaded microparticles were designed using cellulose acetate phthalate as the enteric coating material and spray drying as a production process. The results showed a satisfactory process yield (67.9%), encapsulation efficiency (96.7%), and micrometric characteristics of microparticles (laser-scattering, fluorescent, and scanning electron microscopy). In vitro dissolution studies (USPII-pH change method) showed that Hh-loaded microparticles are able to prevent the release and degradation of the bioactive components in the gastric tract, releasing them into the intestinal environment.

Probing effects of pH change on dynamic response of Claudin-2 mediated adhesion using single molecule force spectroscopy

2008 ◽  
Vol 314 (14) ◽  
pp. 2643-2651 ◽  
Author(s):  
Tong Seng Lim ◽  
Sri Ram Krishna Vedula ◽  
Shi Hui ◽  
P. Jaya Kausalya ◽  
Walter Hunziker ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Single Molecule ◽  
Force Spectroscopy ◽  
Ph Change ◽  
Single Molecule Force Spectroscopy ◽  
Effects Of Ph

Protective effect of two synthetic compounds against chlorsulfuron injury in maize ( Zea mays L.)

2007 ◽  
Vol 55 (3) ◽  
pp. 283-292 ◽  
Author(s):  
G. Stoilkova ◽  
P. Yonova
Keyword(s):  
Zea Mays L ◽  
Shoot Length ◽  
Fresh Weight ◽  
Urea Derivative ◽  
Thiourea Derivative ◽  
Synthetic Compounds ◽  
Sulphydryl Group ◽  
Group Treatments ◽  
Maize Plants ◽  
Derivatives Of

Two new synthetic compounds — urea (B-3) and thiourea (B-6) derivatives of 4-methylpiperazinyl — were investigated as possible antidotes for chlorsulfuron in maize. It was established that the thiourea derivative was a more effective herbicide protector than the urea derivative. The shoot length of maize plants treated with 10 −5 M chlorsulfuron was inhibited 60% compared to the untreated plants, whereas pretreatment with 5×10 −4 M B-6 reduced this inhibition to 23%. Moreover, the decrease of 53% in shoot fresh weight caused by herbicide applied alone was countered almost completely by B-6 with only an 11% loss in fresh weight observed. The results of this investigation show that the urea derivative (B-3) appeared to be ineffective in antidoting the injurious effect of chlorsulfuron. Decreases in root length and fresh weight were also offset by B-6. The more favourable protective activity of the thioureido group in B-6 could be due to the formation of an isomer with isothiourea structure, having a sulphydryl group. Treatments with herbicide and B-3 / B-6 alone or in combination had no significant effect on the parameters of the antioxidative defence system tested.

scholarly journals Cocaine alters the accessibility of endogenous cysteines in putative extracellular and intracellular loops of the human dopamine transporter

1998 ◽  
Vol 95 (16) ◽  
pp. 9238-9243 ◽  
Author(s):  
Jasmine V. Ferrer ◽  
Jonathan A. Javitch
Keyword(s):  
Conformational Change ◽  
Dopamine Transporter ◽  
Membrane Preparation ◽  
Cysteine Residues ◽  
Wild Type ◽  
Rate Of Reaction ◽  
Intracellular Loops ◽  
Derivatives Of ◽  
In Cells

Cocaine and other psychostimulants act by blocking the dopamine transporter. Binding of the cocaine analog, [3H]2-β-carbomethoxy-3-β-(4-fluorophenyl) tropane (CFT) to the dopamine transporter is sensitive to polar sulfhydryl-specific derivatives of methanethiosulfonate (MTS). These reagents preferentially react with water-accessible, reduced cysteines. The human dopamine transporter has 13 cysteines. Their topology is not completely determined. We sought to identify those cysteine residues the modification of which affects CFT binding and to determine the topology of these reactive cysteines. We mutated each of the cysteines, one at a time and in various combinations, to residues that preserved binding and transport, and we tested the sensitivity of each of the mutant transporters to the reagents. One construct, X5C, had five mutated cysteines (C90A, C135A, C306A, C319F, and C342A). Using a membrane preparation in which both extracellular and intracellular cysteines could be accessible, we found that CFT binding in X5C, as compared with wild-type transporter, was two orders of magnitude less sensitive to MTS ethylammonium (MTSEA). The wild-type cysteines were substituted back into X5C, one at a time, and these constructs were tested in cells and in membranes. Cys-90 and Cys-306 appear to be extracellular, and Cys-135 and Cys-342 appear to be intracellular. Each of these residues is predicted to be in extramembranous loops. The binding of cocaine increases the rate of reaction of MTSEA and MTS ethyltrimethylammonium with the extracellular Cys-90 and therefore acts by inducing a conformational change. Cocaine decreases the rate of reaction of MTSEA with Cys-135 and Cys-342, acting either directly or indirectly on these intracellular residues.

Effect of pH on flux during ultrafiltration of sweet whey and buttermilk

1995 ◽  
Vol 62 (3) ◽  
pp. 441-449 ◽  
Author(s):  
Harohally G. Ramachandra Rao ◽  
Michael J. Lewis ◽  
Alistair S. Grandison
Keyword(s):  
Concentration Polarization ◽  
Combined Effects ◽  
Ph Change ◽  
Deposit Formation ◽  
Effect Of Ph ◽  
Flux Decline ◽  
Sweet Whey ◽  
Effects Of Ph

SummaryThe flux patterns for sweet whey and buttermilk were strongly influenced by pH. Increasing the pH of buttermilk from 6·6 to 8·0 tended to reduce initial flux values and reduce deposit formation on the membrane as indicated by lower values for the fouling coefficient. Flux was mostly controlled by concentration polarization. Reducing the pH below 6·6 increased the flux but caused more deposit on the membrane as indicated by high fouling coefficient values. Almost the opposite was found for sweet whey. The initial flux increased as pH increased, followed by considerable flux decline, which was linked to greater fouling of the membrane. Reducing the pH reduced the initial flux considerably but also reduced further fouling. These changes are thought to be brought about by the combined effects of pH change on the proteins and minerals, and in particular on calcium.

scholarly journals Bacteria and Mold Spore Heat Resistance in Guava Juice and Its Control by pH and Sodium Benzoate

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Evelyn ◽  
Chairul
Keyword(s):  
Sodium Benzoate ◽  
Thermal Inactivation ◽  
Resistant Bacteria ◽  
Inactivation Kinetics ◽  
Ph Change ◽  
Talaromyces Flavus ◽  
Effects Of Ph ◽  
Mold Spore ◽  
Influence Of Ph ◽  
Kinetics Of

Heat-resistant bacteria and molds can survive the pasteurization conditions used in high-acid fruit juices. The objective of this study was to evaluate the log reductions and thermal inactivation kinetics of spores of Bacillus subtilis bacteria and ascospores of Talaromyces flavus and Eupenicillium javanicum molds under influence of pH and sodium benzoate preservative. The spores were suspended in guava juice, processed at 90-100°C for B. subtilis and at 80-90°C for T. flavus and E. javanicum, and decimal reduction ( D ) values were estimated from the log survivor curves. Next, the effects of pH change (3.5-4.5) and 0.015% sodium benzoate addition on the D values of spores were investigated. Lower D values were obtained at higher temperatures ( D 100 ° C value of 2.32 min vs. D 90 ° C value of 15.33 min for B. subtilis, D 90 ° C value of 2.96 min vs. D 80 ° C value of 59.52 min for T. flavus, and D 90 ° C value of 1.58 min vs. D 80 ° C value of 21.32 min for E. javanicum). The D values decreased further (to 1.8 min at 100°C for B. subtilis, to 2.33 min at 90°C for T. flavus, and to 1.49 min at 90°C for E. javanicum) when the pH of guava juice was decreased from 4.1 to 3.5. Inclusion of sodium benzoate in pH 3.5 juice enhanced the thermal inactivation of spores ( D 100 ° C value decreased to 1.4 min for B. subtilis, to 1.98 min for T. flavus, and to 1.34 min for E. javanicum). To conclude, the combination of low pH and sodium benzoate provided the best method for spore inactivation, which could enhance food safety and extend food’s shelf life.

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