Search

The analysis of the wild-type and the mutant forms of cinnamyl alcohol dehyrdogenase isoform 2 (CAD2) when subjected to site-directed mutagenesis (S212D) and overexpression, reveal that the phosphate moiety of NADPH is identified through S212 and the structural characteristics for NADPH specificity. The enzymatic binding positions of the coniferyl alcohol substrate undergo physical interaction with the 2'-phosphate binding region. The single mutation S212D is responsible for reducing the catalytic performance of CAD2 where NADP+ is the coenzyme.

In order to optimize the fullerene synthesis process based on an electric arc with graphite electrodes, an experimental study using a reactor geometry optimized for plasma spectroscopy is performed to correlate the arc properties with the fullerene formation. Emission spectroscopy studies based on the use of the Swan C2(0,0) rotational system emission spectra were carried out to determine the plasma temperature. The self-absorption effect in the d3Πg, v' = 0 → a3Πu, v" = 0 C2 band was used for column density determination of C2 molecules and temperatures under various arc discharge conditions. Discharge parameters (pressure, arc current, electrode gap length) are optimized with respect both to the anode erosion rate and the weight percentage of toluene extractable fullerenes in the soot. Local plasma discharge conditions (temperature and density fields) are evaluated and correlated with the C60 yield. Steep temperature gradients around the arc fringes are shown to provide optimal conditions for C60 production. [ABSTRACT FROM AUTHOR]

Copyright of Chemical Monthly / Monatshefte für Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Chalcones are polyphenols that belong to the flavonoids family, known for their broad pharmacological properties. They have thus attracted the attention of chemists for their obtention and potential activities. In our study, a library of compounds from 2'-hydroxychalcone's family was first synthesized. A one-step mechanochemical synthesis via Claisen-Schmidt condensation reaction under ball mill conditions was studied, first in a model reaction between a 5'-fluoro-2'-hydroxyacetophenone and 3,4-dimethoxybenzaldehyde. The reaction was optimized in terms of catalysts, ratio of reagents, reaction time, and influence of additives. Among all assays, we retained the best one, which gave the highest yield of 96% when operating in the presence of 1 + 1 eq. of substituted benzaldehyde and 2 eq. of KOH under two grinding cycles of 30 min. Thus, this protocol was adopted for the synthesis of the selected library of 2'-hydroxychalcones derivatives. The biological activities of 17 compounds were then assessed against Plasmodium falciparum , Leishmania donovani parasite development, as well as IGR-39 melanoma cell lines by inhibiting their viability and proliferation. Compounds 6 and 11 are the most potent against L. donovani, exhibiting IC 50 values of 2.33 µM and 2.82 µM, respectively, better than the reference drug Miltefosine (3.66 µM). Compound 15 presented the most interesting antimalarial activity against the 3D7 strain, with IC 50 = 3.21 µM. Finally, chalcone 12 gave the best result against IGR-39 melanoma cell lines, with an IC 50 value of 12 µM better than the reference drug Dacarbazine (IC 50 = 25 µM).

The synthesis and antiplasmodial evaluation of new hybrids combining the pharmacophore structures of artemisinin, ciprofloxacin or norfloxacin, and 7-chloroquinoline are reported in this study. The first step for all of the syntheses is the obtainment of key piperazine esters intermediates bearing the drugs ciprofloxacin and norfloxacin. Using these platforms, 18 final compounds were synthesized through a multistep procedure with overall yields ranging between 8 and 20%. All compounds were screened for their antiplasmodial activity against the chloroquine-resistant Plasmodium falciparum FcB1 strain. Compounds 20 , 21 , 22 , and 28 , bearing an artesunate fragment with ciprofloxacin, exhibited IC 50 values in the range of 3.5-5.4 nM and excellent selectivity indices. Among the compounds bearing the artesunate moiety on the norfloxacin, two of them, 23 and 24 , afforded IC 50 values of 1.5 nM and 1.9 nM, respectively. They also showed excellent selectivity indices. The most potent compounds were also evaluated against the CQ-resistant Dd2 strain of Plasmodium falciparum , demonstrating that those compounds incorporating the artesunate fragment were the most potent. Finally, the combination of artesunate with either ciprofloxacin or norfloxacin moieties in a single molecular entity proved to substantially enhance the activity and selectivity when compared to the administration of the unconjugated counterparts artesunate/ciprofloxacin and artesunate/norfloxacin.

Hydrazone compounds represent an important area of research that includes, among others, synthetic approaches and biological studies. A series of 17 hydrazones have been synthesized by mechanochemical means. The fragments chosen were phenolic and furanyl aldehydes coupled with 12 heterocyclic hydrazines or hydrazinamides. All compounds can be obtained quantitatively when operating on a planetary ball mill and a maximum reaction time of 180 min (6 cycles of 30 min each). Complete spectroscopic analyses of hydrazones revealed eight compounds ( 3 - 5 , 8 - 11 , 16 ) present in one geometric form, six compounds ( 1 , 2 , 13 - 15 ) present in two isomeric forms, and three compounds ( 6 , 7 , 12 ) where one rotation is restricted giving rise to two different forms. The single crystal X-ray structure of one of the hydrazones bearing the isoniazid fragment ( 8 ) indicates a crystal lattice consisting of two symmetry-independent molecules with different geometries. All compounds obtained were tested for anti-infectious and antibacterial activities. Four compounds ( 1 , 3 , 5 and 8 ) showed good activity against Mycobacterium tuberculosis , and one ( 7 ) was very potent against Staphylococcus aureus . Most interesting, this series of compounds displayed very promising antileishmanial activity. Among all, compound 9 exhibited an IC 50 value of 0.3 µM on the Leishmania donovani intramacrophage amastigote in vitro model and a good selectivity index, better than miltefosine, making it worth evaluating in vivo.