An overview of azoles targeting sterol 14α-demethylase for antileishmanial therapy

The azole antifungal drugs are an important class of chemotherapeutic agents with broad-spectrum of activity against yeasts and filamentous fungi, act in the ergosterol biosynthetic pathway through inhibition of the cytochrome P450-dependent enzyme sterol 14α-demethylase. Azole antifungals have also been repurposed for treatment of tropical protozoan infections including human leishmaniasis. Recent advances in molecular biology and computational chemistry areas have increased our knowledge about sterol biochemical pathway in Leishmania parasites. Based on the importance of sterol biosynthetic pathway in Leishmania parasites, we reviewed all studies reported on azoles for potential antileishmanial therapy along their structural and biological aspects. This review may help medicinal chemists for design of new azole-derived antileishmanial drugs.

In vitro antileishmanial activity of novel azoles (3-imidazolylflavanones) against promastigote and amastigote stages of Leishmania major

Leishmaniasis is a protozoan infectious disease widely distributed all around the world. First line drugs including antimoniales are insufficient due to resistance in endemic areas and high toxicity. Azole antifungals like ketoconazole (KCZ) are also used as antileishmanial agents for several decades. In the present study, we evaluated in vitro antileishmanial effects of new azole antifungals namely 3-imidazolylflavanones (IFs) and their oximes (IFOs) against Leishmania major (L. major) parasites. The obtained results showed remarkable effect of our compounds on promastigote and amastigote stages of L. major. In particular, the 4-chloro analog of flavanone (IF-2) and 3-chloro substituted flavanone oxime (IFO-3) with IC₅₀ values ≤8.9μg/mL were 8-fold more potent than KCZ (IC₅₀=72μg/mL) against promastigote form of L. major. In amastigote stage, the compounds IF-2 and IFO-2 decreased the mean number of infected macrophages (MIR) more than KCZ (p<0.005). In addition, compounds IF-1, IF-2, IF-4, IFO-2, IFO-3 and IFO-5 decreased the mean number of amastigotes per macrophages (MNAPM) significantly more than KCZ (p<0.005). All compounds decreased both MIR and MNAPM significantly more than control (p<0.001). Compounds IF-2 and IFO-2 with parasite survival of 7.70% and 20% had the highest inhibition on intracellular amastigotes. Although most of compounds displayed acceptable selectivity index, compound IF-2 had the highest CC₅₀ value (115.4μg/mL) and SI (383.3). We concluded that our new synthetic azoles displaying potent activity against L. major could be considered as new hits for drug development in the field of antileishmanial therapy.

New tacrine-derived AChE/BuChE inhibitors: Synthesis and biological evaluation of 5-amino-2-phenyl-4H-pyrano[2,3-b]quinoline-3-carboxylates

A series of poly-functionalized tacrine-derived compounds namely 5-amino-2-phenyl-4H-pyrano[2,3-b]quinoline-3-carboxylates were designed and synthesized as cholinesterases inhibitors. The in vitro inhibition assay against AChE and BuChE demonstrated that most of compounds had potent AChE inhibitory with reserving potential of BuChE inhibition. Among them, compound 6i bearing a 4-(3-bromophenyl) moiety showed the most potent activity against AChE/BuChE (IC₅₀s values of 0.069 and 1.35 μM, respectively). The anti-AChE activity of 6i was five times more than that of tacrine. The SAR study revealed that chloro/bromo substituent at ortho or meta position of the 4-phenyl ring can improve the anticholinesterase activity.

Management of multi-drug resistant Helicobacter pylori infection by supplementary, complementary and alternative medicine; a review

Helicobacter pylori is recognized as the most common bacterial pathogens colonizing the gastric epithelium of nearly half of the world's population. This bacterium is the main etiological cause of gastroduodenal ulcers, and more importantly as the substantial risk factor for development of gastric cancer. The emergence and rapid increase in the prevalence of multi-drug resistant phenotypes have posed major pitfalls in effectiveness of various treatment regimens and eradication strategies against H. pylori infections. Several natural products and supplementary food components have been reported to have established anti-H. pylori activity. Herein, we review the application and efficacy of some specific natural products and foodstuffs such as milk, bee products (honey and propolis), fish oil, vitamins C and E, and also a nickel free-diet used as anti-H. pylori alternative treatment regimens.

β-Ionone and its analogs as promising anticancer agents

β-Ionone is an end-ring analog of β-carotenoids which widely distributed in fruit and vegetables. Recent studies have demonstrated anti-proliferative, anti-metastatic and apoptosis induction properties of β-ionone in vitro and in vivo. Also, the studies have focused on investigating the β-ionone action on different types of malignant cells and the possible mechanisms of action. Moreover, the quest of new synthetic β-ionone-based compounds possessing anti-proliferative, anti-metastatic and apoptosis induction activities may enable the discovery of compounds which can be used in combination regimes thus overcoming tumor resistance to conventional anticancer agents. These new agents will also be useful for targeting distinct signaling pathways, to activate selectively mechanisms for apoptosis in cancer cells but devoid of undesirable side effects. In this paper, we reviewed the potentialities of β-ionone and related compounds in cancer prevention and chemotherapy.

Quinoline-based imidazole-fused heterocycles as new inhibitors of 15-lipoxygenase

A series of 2-chloro-quinoline-based imidazopyridines 6a-l and imidazothiazoles 6m-o bearing a bulky alkylamine side chain were synthesized as soybean 15-LOX inhibitors. The target compounds 6a-o were prepared via one-pot reaction of 2-chloroquinoline-3-carbaldehyde (3), heteroaromatic amidine 4, and alkyl isocyanides 5, in the presence of NH4Cl. All compounds showed significant anti-15-LOX activity (IC50 values ≤40 μM). Among the title compounds, the imidazo[2,1-b]thiazole derivative 6n bearing a tert-butylamine moiety showed the highest activity against soybean 15-LOX enzyme.

Recent advances of cytotoxic chalconoids targeting tubulin polymerization: Synthesis and biological activity

Since microtubules have an important role in mitosis and other vital cellular functions, tubulin-targeting chemotherapy has been received growing attention in anticancer drug design and development. It was found that a number of naturally occurring compounds including distinct chalcones exert their effect by inhibition of tubulin polymerization. After the identification of tubulin polymerization as potential target for chalcone-type compounds, extensive researches have been made to design and synthesis of new anti-tubulin chalconoids. Although diverse chalcones have found to be potent anticancer agents but in the present review, we focused on the recently reported tubulin polymerization inhibitors from chalcone origin and related synthetic compounds, and their detailed synthetic methods and biological activities.

The importance of triazole scaffold in the development of anticonvulsant agents

Epilepsy is one of the most important neurological disorders with high prevalence worldwide. Many epileptic patients are not completely treated with available drugs and need multiple therapies. Also, many antiepileptic drugs have shown unwanted side effects and drug interactions. Therefore there are continuing interests to find new anticonvulsant drugs. Triazole ring has been found in the structure of many compounds with diverse biological effects. Due to the success of several triazole-containing drugs that entered the pharmaceutical market as CNS-active drugs, this class of heterocyclic compounds has great importance for discovery and development of new anticonvulsant drugs. In this article, we have tried to summarize the latest efforts which have been made in the design and development of triazole-derived anticonvulsant agents.

A new boronic acid fluorescent sensor based on fluorene for monosaccharides at physiological pH

Fluorescent boronic acids are very useful fluorescent sensor for detection of biologically important saccharides. Herein we synthesized a new fluorene-based fluorescent boronic acid that shows significant fluorescence changes upon addition of saccharides at physiological pH. Upon addition of fructose, sorbitol, glucose, galactose, ribose, and maltose at different concentration to the solution of 7-(dimethylamino)-9,9-dimethyl-9H-fluoren-2-yl-2-boronic acid (7-DMAFBA, 1), significant decreases in fluorescent intensity were observed. It was found that this boronic acid has high affinity (K(a)=3582.88 M(-1)) and selectivity for fructose over glucose at pH=7.4. The sensor 1 showed a linear response toward d-fructose in the concentrations ranging from 2.5×10(-5) to 4×10(-4) mol L(-1) with the detection limit of 1.3×10(-5) mol L(-1).