Structure–activity relationships in platelet-activating factor. Part 14: Synthesis and biological evaluation of piperazine derivatives with dual anti-PAF and anti-HIV-1 activity

Piperazine, a Key Substructure for Antidepressants: Its Role in Developments and Structure-Activity Relationships

Depression is the single largest contributor to global disability with a huge economic and social burden on the world. There are a number of antidepressant drugs on the market, but treatment-resistant depression and relapse of depression in a large number of patients have increased problems for clinicians. One peculiarity observed in most of the marketed antidepressants is the presence of a piperazine substructure. Although piperazine is also used in the optimization of other pharmacological agents, it is almost extensively used for the development of novel antidepressants. One common understanding is that this is due to its favorable CNS pharmacokinetic profile; however, in the case of antidepressants, piperazine plays a much bigger role and is involved in specific binding conformations of these agents. Therefore, in this review, a critical analysis of the significance of the piperazine moiety in the development of antidepressants has been performed. An overview of current developments in the designing and synthesis of piperazine-based antidepressants (2015 onwards) along with SAR studies is also provided. The various piperazine-based therapeutic agents in early- or late-phase human testing for depression are also discussed. The preclinical compounds discussed in this review will help researchers understand how piperazine actually influences the design and development of novel antidepressant compounds. The SAR studies discussed will provide crucial clues about the structural features and optimizations required to enhance the efficacy and potency of piperazine-based antidepressants.

Syntheses and characterization of monobasic tridentate Cu(ii) Schiff-base complexes for efficient oxidation of 3,5-di-tert-butylcatechol and oxidative bromination of organic substrates

Enhanced bifunctional catalytic activities are shown by monobasic tridentate Cu(ii) Schiff-base complexes.

In vivo effect of two first-line ART regimens on inflammatory mediators in male HIV patients

BACKGROUND

Persistent immune activation and inflammation are lying behind HIV-infection even in the setting of ART mediated viral suppression. The purpose of this study is to define the in vivo effect of two first-line ART regimens on certain inflammatory mediators in male HIV patients.

METHODS

Male, naive, HIV-infected volunteers were assigned either to tenofovir-DF/emtricitabine/efavirenz (Group_T) or abacavir/lamivudine/efavirenz (Group_A). Platelet Activating Factor (PAF) levels and metabolic enzymes together with HIV-implicated cytokines (IL-1beta, IL-6, IL-8, IL-10, IL-12p70, TNFa) and VEGF were determined for a 12-month period. Differences within each group were determined by non-parametric Friedman and Wilcoxon test, while the differences between the groups were checked by ANOVA repeated measures.

RESULTS

Both ART regimens present pronounced effect on inflammatory mediators, resulting in decreased PAF levels and Lipoprotein-associated phospholipase A2 (Lp-PLA2) activity for tenofovir-containing regimen and same as baseline PAF levels with a peak though at the 3rd month as well as elevated Lp-PLA2 activity for abacavir-containing regimen.

CONCLUSIONS

Studies regarding the effect of first-line ART regimens on inflammation may be beneficial in preventing chronic morbidities during HIV-treatment. From this point of view, the present study suggests an anti-inflammatory effect of tenofovir-containing ART, while the temporary increase of PAF levels in abacavir-containing ART may be the link between the reported cardiovascular risk and abacavir administration.

Advances in brain targeting and drug delivery of anti-HIV therapeutic agents

INTRODUCTION

Human immunodeficiency virus (HIV) is a neurotropic virus that enters the central nervous system (CNS) early in the course of infection. Although antiretroviral drugs are able to eliminate the majority of the HIV virus in the bloodstream, however, no specific treatment currently exist for CNS infections related to HIV. This is mainly attributed to the poor penetrability of antiretroviral therapy across the blood-brain barrier (BBB), and the protective nature of the BBB. Therefore, in order to increase the efficacy of anti-HIV drugs, novel drug delivery methodologies that can exhibit activity in the CNS are most needed and warranted.

AREAS COVERED

In this review article, the authors discussed the challenges with delivering drugs to the brain especially under HIV infection pathophysiology status. Also, they discussed the approaches currently being investigated to enhance brain targeting of anti-HIV drugs. A literature search was performed to cover advances in major approaches used to enhance drug delivery to the brain.

EXPERT OPINION

If drugs could reach the CNS in sufficient quantity by the methodologies discussed, mainly through intranasal administration and the utilization of nanotechnology, this could generate interest in previously abandoned therapeutic agents and enable an entirely novel approach to CNS drug delivery.

Acute oral toxicity evaluations of some zinc(II) complexes derived from 1-(2-salicylaldiminoethyl)piperazine Schiff bases in rats

The current study described the synthesis and the in vivo acute oral toxicity evaluations in Sprague Dawley rats. The compounds were characterized by elemental analyses, LC-MS, FTIR, ¹H NMR, ¹³C NMR and UV-visible spectroscopy. In the acute toxicity study, a single administration of the compounds was performed orally to the rats at the single doses of 2000 mg/kg and they were then monitored for possible side effects, mortality or behavioral changes up to 14 days. The serum level of aspartate (AST), alanine aminotransferases (ALT), alkaline phosphate (ALP), triglyceride, high density lipoprotein (HDL), immunoglobulins (GAM) and the C-reactive proteins did not significantly change. The hematological indices white blood cells (WBC), haematocrit (HCT), red blood cells (RBC), mean corpuscular volume (MCV), mean corpuscular haemoglobin concentration (MCHC), and mean corpuscular hemoglobin (MCH) were within the normal range. The renal function indices examined were also within the reference range. Generally, the compounds exhibited low toxic effects as required for further in vivo therapeutic studies.

Synthesis of new heterometallic macromolecules: their DNA binding, cleavage activity and in vitro model electrochemotherapy study

The homodinuclear C(16)H(30)N(8)O(5)Sn(2)Cl(4) (1), heterotetranuclear C(16)H(38)N(8)O(9)Sn(2)Cu(2)Cl(8) (2) and C(16)H(38)N(8)O(9)Sn(2)Mn(2)Cl(8) (3) macrocyclic complexes were synthesized and characterized by elemental analysis, spectroscopic techniques and molar conductance measurements. The interaction studies of 1-3 with calf thymus DNA (CT-DNA) were carried out by UV-vis titration, fluorescence, cyclic voltammetry and viscosity measurements. These results were further authenticated by carrying out interaction studies of 1-3 with plasmid pBR322 DNA employing gel electrophoresis. To overcome the dose resistance, auto toxicity of the drugs, a model study based on electrochemotherapy (ECT) was carried out and the results were compared in the presence and in the absence of the applied electrical potential.

Synthesis of new piperazine derived Cu(II)/Zn(II) metal complexes, their DNA binding studies, electrochemistry and anti-microbial activity: validation for specific recognition of Zn(II) complex to DNA helix by interaction with thymine base

New 3,4:9,10-dibenzo-2,11-dihydroxy-1,12-bispiperazine-5,8-dioxododecane complexes [C(24)H(36)N(4)O(6)Cu] (1), [C(24)H(32)N(4)O(4)Zn] (2) have been synthesized and characterized by elemental analysis, IR, NMR, Mass, EPR, UV-vis spectroscopy and molar conductance measurements. The complexes are non-ionic in nature and possess octahedral geometry around Cu(2+), Zn(2+) central metal ions. The binding studies of 1 and 2 with calf thymus DNA (CT-DNA) were investigated by UV-vis, fluorescence, cyclic voltammetery and viscosity measurements. The calculated binding constant K(b) for 1 and 2 obtained from UV-vis absorption studies was 7.6x10(3)M(-1), 80.8x10(4)M(-1), respectively. The intrinsic binding constants were also estimated to be 7.0x10(4)M(-1) and 7.53x10(5)M(-1) for 1 and 2, respectively by using emission titrations. These experimental results suggest that complexes are groove binders and interact to CT-DNA with different affinities. Both the complexes in presence and absence of CT-DNA show quasireversible wave corresponding to Cu(II)/Cu(I) and Zn(II)/Zn(I) redox couple. The changes in E(1/2), DeltaE, I(pa)/I(pc) ascertain the interaction of 1 and 2 with CT-DNA. Further, decrease in viscosity of CT-DNA with increasing concentration of complexes was observed. In vitro, antimicrobial activity against fungi A. brassicicola, A. niger and bacteria E. coli, P. aeruginosa of complexes were carried out, which indicate that complex 2 is more active against both fungal and bacterial strains as shown by % inhibition data.

SOLUBLE CD40 LIGAND IN DEMENTIA

Some 15-20% of the population over the age of 65 years suffer from dementia, currently one of the leading causes of death behind cardiovascular diseases, cancer and cerebrovascular diseases. The major forms of dementia share in common overactivation of the CD40-CD40-L complex, leading to high levels of proinflammatory cytokine production by immune cells of the central nervous system (CNS), including microglia and astrocytes. Consequently, both neuronal survival and signaling are negatively affected, leading to the characteristic progressive loss of higher cortical functions. We have reviewed the literature concerning the involvement of this complex in the pathology of three major forms of dementia: Alzheimer's-type, HIV-associated and vascular dementia. This is followed by a discussion of current preclinical and clinical therapies that may influence this interaction, and thus point the way toward a future neuroimmunological approach to inhibiting the effects of CD40-CD40-L in neuropsychiatric disease.