Mini Reviews in Medicinal Chemistry - Volume 14, Issue 13, 2014

Adenosine (Ado) and some non-adenosine (non-Ado) nucleosides including inosine (Ino), guanosine (Guo) and uridine (Urd) are modulatory molecules in the central nervous system (CNS), regulating different physiological and pathophysiological processes in the brain such as sleep and epilepsy. Indeed, different drugs effective on adenosinergic system (e.g., Ado metabolism inhibitors, agonists and antagonists of Ado receptors) are being used in drug development for the treatment of epileptic disorders. Although (i) endogenous Ino, Guo and Urd showed anticonvulsant/antiepileptic effects (e.g., in quinolinic acid - induced seizures and in different epilepsy models such as hippocampal kindling models), and (ii) there is a need to generate new and more effective antiepileptic drugs for the treatment of drug-resistant epilepsies, our knowledge about antiepileptic influence of non-Ado nucleosides is far from complete. Thus, in this review article, we give a short summary of anticonvulsant/antiepileptic effects and mechanisms evoked by Ino, Guo, and Urd. Finally, we discuss some non-Ado nucleoside derivatives and their structures, which may be candidates as potential antiepileptic agents.

In recent years, the ongoing need for novel pharmaceuticals to be introduced in human medicine has substantially benefited from the widespread research activity on the role of bioactive microbial compounds involved in the regulation of interactions with other organisms. A good example is represented by 3-O-methylfunicone, a benzo-γ-pyrone metabolite at first characterized on account of the antifungal aptitude of the producing strain, which has later become more valuable for its antiproliferative and pro-apoptotic properties resulting in a series of studies on human tumor cell lines. An overview of aspects concerning molecular structure, sources, and biological properties of this compound is offered in the present paper.

Progress in cancer treatment remains challenging because of the great nature of tumor cells to be drug resistant. However, advances in the field of nanotechnology have enabled the delivery of drugs for cancer treatment by passively and actively targeting to tumor cells with nanoparticles. Dramatic improvements in nanotherapeutics, as applied to cancer, have rapidly accelerated clinical investigations. In this review, drug-targeting systems using nanotechnology and approved and clinically investigated nanoparticles for cancer therapy are discussed. In addition, the rationale for a nanotechnological approach to cancer therapy is emphasized because of its promising advances in the treatment of cancer patients.

Despite the efforts in controlling the parasite and infection, and the significant progress achieved in recent years in its treatment, malaria is still prevalent in many regions and out of control in others. The repertoire of alternatives to fight malaria is being expanded, not only by designing new drugs but also by developing improved drug delivery systems able to enhance the antimalarial efficiency of conventional and new drugs. Among the new drugs that have been investigated, several publications report the use of porphyrin derivatives as antimalarials but their efficiency is contradictory. The low activity of porphyrins seems to be associated with low dispersibility and bioavailability. In this respect, Nanotechnology can provide efficient solutions to enhance bioavailability and delivery of conventional and new antimalarials, in order to assure high enough efficiency levels to inactivate the parasite. Thus, in this review we highlight the use of drug delivery systems for conventional and new antimalarials and we propose the encapsulation of porphyrins as a promising alternative for development of anti-malarial formulations.

The biodistributions and in vivo kinetics of chemically prepared neoglycoproteins have been examined previously and are reviewed here. A variety of mono- and oligosaccharides may be conjugated onto a protein surface using chemical methods. The kinetics and organ-specific accumulation profiles of these glycoconjugates, introduced through intravenous injection, have been analyzed using conventional dissection studies as well as noninvasive methods, such as SPECT, PET, or fluorescence imaging. These studies have revealed glycan-dependent protein distribution kinetics that may be useful for pharmacological and diagnostic applications.

Pyrazoles have a representative history in medicinal chemistry. These nucleuses, molecules of synthetic origin, constitute a group of nitrogen heterocyclic compounds. Available literature particularly shows a variety of pyrazoles with antioxidant effect. In this connection, this review describes the advances on the green synthesis of pyrazoles with antioxidant activity, mainly covering the data published over the last seven years (2008-2014).

Pyridazinone derivatives and their related analoges were introduced for gastric antiulcer and antisecretory activities. Selected compounds were applied to ulcer models and showed their antiulcer and anti secretary activities. Some pyridazinone compounds are recently reported as H3R antagonists. Some amine analogs of pyridazinones, pyridazinone– phenethylamines and 4,5-fused pyridazinones showed histamine H3R antagonist activity with significant affinity for rat and human H3R. These pyridazinone analogs also showed excellent selectivity and metabolic stability, with adequate pharmacokinetics.

Micellar structures formed by self-assembling Congo red molecules bind to proteins penetrating into functionrelated unstable packing areas. Here, we have used Congo red - a supramolecular protein ligand to investigate how the intramolecular structural changes that take place in antibodies following antigen binding lead to complement activation. According to our findings, Congo red binding significantly enhances the formation of antigen-antibody complexes. As a result, even low-affinity transiently binding antibodies can participate in immune complexes in the presence of Congo red, although immune complexes formed by these antibodies fail to trigger the complement cascade. This indicates that binding of antibodies to the antigen may not, by itself, fulfill the necessary conditions to generate the signal which triggers effector activity. These findings, together with the results of molecular dynamics simulation studies, enable us to conclude that, apart from the necessary assembling of antibodies, intramolecular structural changes generated by strains which associate high- affinity bivalent antibody fitting to antigen determinants are also required to cross the complement activation threshold.