Chemotherapy of leishmaniasis part XIII: Design and synthesis of novel heteroretinoid-bisbenzylidine ketone hybrids as antileishmanial agents

Anticancer perspectives of monocarbonyl analogs of curcumin: A decade (2014-2024) review

Monocarbonyl analogs of curcumin (MACs) represent structurally modified versions of curcumin. The existing literature indicates that MACs exhibit enhanced anticancer properties compared with curcumin. Numerous research articles in recent years have emphasized the significance of MACs as effective anticancer agents. This review focuses on the latest advances in the anticancer potential of MACs, from 2014 to 2024, including discussions on their mechanism of action, structure-activity relationship (SAR), and in silico molecular docking studies.

Identification of potential antileishmanial 1,3-disubstituted-4-hydroxy-6-methylpyridin-2(1H)-ones, in vitro metabolic stability, cytotoxicity and molecular modeling studies

We report the synthesis and in vitro evaluation of 1,3-disubstituted-4-hydroxy-6-methylpyridin-2(1H)-one derivatives against Leishmania donovani. Amongst the compound library synthesized, molecules 3d, 3f, 3h, 3i, 3l, and 3m demonstrated substantial dose-dependent killing of the promastigotes. Their IC₅₀ values range from 55.0 to 77.0 μg/ml, with 3m (IC₅₀ 55.75 μg/ml) being equipotent with amphotericin B (IC₅₀ 50.0 μg/ml, used as standard). The most active compound 3m, is metabolically stable in rat liver microsomes. Furthermore, the molecules are highly specific against leishmania as shown by their weak antibacterial and antifungal activity. In vitro cytotoxicity studies show the compounds lack any cytotoxicity. Furthermore, molecular modeling studies show plausibility of binding to Leishmania donovani topoisomerase 1 (LdTop1). Structure activity relationships reveal bulky substitutions on the pyridone nitrogen are well-tolerated, and such compounds have better binding affinity. Intramolecular hydrogen bonds confer some rigidity to the molecules, rendering a degree of planarity akin to topotecan. Taken together, we emphasis the merits of molecules possessing the 1,3-disubstituted-4-hydroxy-6-methylpyridin-2(1H)-one skeleton as potential antileishmanial agents warranting further investigation.

In vitro evaluation and in vivo efficacy of nitroimidazole-sulfanyl ethyl derivatives against Leishmania (V.) braziliensis and Leishmania (L.) mexicana

The aim of this study was to synthesize several small molecules of the type 5-nitroimidazole-sulfanyl and evaluate biological properties against the main Leishmania species that cause cutaneous leishmaniasis in Venezuela. Final compounds 4-7 were generated through simple nucleophilic substitution of 1-(2-chloroethyl)-2-methyl-5-nitroimidazole 3 with 2-mercaptoethanol, 1-methyl-2-mercaptoethanol, and 2-thyolacetic acid derivative. Compound 8 was synthesized via a coupling reaction between 7 and (S)-Methyl 2-amino-4-methylpentanoate hydrochloride. The inhibitory concentrations of (3, 4, 7, 8) against Leishmania (L.) mexicana and (V.) braziliensis in promastigotes and experimentally infected macrophages were determined by in vitro activity assays. Compounds 7 and 8 shown high activity against both species of Leishmania and were selected for the in vivo evaluation. Animals were infected with promastigotes of the two species and divided into four groups of ten (10) animals and a control group. Intralesional injection way was used for the treatment. The parasitological diagnostic after treatment was obtained by PCR using species specific oligonucleotides. The two Leishmania species were susceptible to compounds 7 and 8 in vivo assays. The results indicated that both compounds reduce significantly (96%) the size of the lesion and cure 63% of the mice infected with L (L) mexicana or L (V) braziliensis as was determined by PCR. The results are indicating that both compounds may represent an alternative treatment for these two Leishmania species.

Quinoline Based Monocarbonyl Curcumin Analogs as Potential Antifungal and Antioxidant Agents: Synthesis, Bioevaluation and Molecular Docking Study

In search for new fungicidal and free radical scavenging agents, we synthesized a focused library of 2-chloroquinoline based monocarbonyl analogs of curcumin (MACs). The synthesized MACs were evaluated for in vitro antifungal and antioxidant activity. The antifungal activity was evaluated against five different fungal strains such as Candida albicans, Fusarium oxysporum, Aspergillus flavus, Aspergillus niger, and Cryptococcus neoformans, respectively. Most of the synthesized MACs displayed promising antifungal activity compared to the standard drug Miconazole. Furthermore, molecular docking study on a crucial fungal enzyme sterol 14α-demethylase (CYP51) could provide insight into the plausible mechanism of antifungal activity. MACs were also screened for in vitro radical scavenging activity using butylated hydroxytoluene (BHT) as a standard. Almost all MACs exhibited better antioxidant activity compared to BHT.

Recent Advances in the Discovery of Novel Antiprotozoal Agents

Parasitic diseases have serious health, social, and economic impacts, especially in the tropical regions of the world. Diseases caused by protozoan parasites are responsible for considerable mortality and morbidity, affecting more than 500 million people worldwide. Globally, the burden of protozoan diseases is increasing and is been exacerbated because of a lack of effective medication due to the drug resistance and toxicity of current antiprotozoal agents. These limitations have prompted many researchers to search for new drugs against protozoan parasites. In this review, we have compiled the latest information (2012-2017) on the structures and pharmacological activities of newly developed organic compounds against five major protozoan diseases, giardiasis, leishmaniasis, malaria, trichomoniasis, and trypanosomiasis, with the aim of showing recent advances in the discovery of new antiprotozoal drugs.

An overview of molecular hybrids in drug discovery

INTRODUCTION

The hybridization of biologically active molecules is a powerful tool for drug discovery used to target a variety of diseases. It offers the prospect of better drugs for the treatment of a number of illnesses including cancer, malaria, tuberculosis and AIDS. Hybrid drugs can provide combination therapies in a single multi-functional agent and, by doing so, be more specific and powerful than conventional classic treatments. This research field is in great expansion and attracts many researchers worldwide.

AREA COVERED

This review covers the main research published between early 2013 to mid-2015 and takes into account several previous reviews on the subject. Its intention is to showcase the most recent advances reported towards the development of molecular hybrids in drug discovery. Particular attention is given to anticancer hybrids throughout the review.

EXPERT OPINION

Current advances show that molecular hybrids of biologically active molecules can lead to powerful therapeutics. Natural products play a key role in this field. It is also believed that toxin hybrids present a great opportunity for future progress and should be further explored. Furthermore, the synthesis of hybrid organometallics should be systematically studied as it can lead to potent drugs. The crucial requirement for growth still remains the efficacy of synthesis. Hence, the development of efficient synthetic methods allowing rapid access to diverse series of hybrids must be further investigated by researchers.