Synthesis and potential antineoplastic activity of dehydroabietylamine imidazole derivatives

Novel drug-drug salt crystals of metformin with ibuprofen or naproxen: Improved solubility, dissolution rate, and synergistic antinociceptive effects

As the monotherapy of available analgesics is usually accompanied by serious side effects or limited efficacy in the management of chronic pain, multimodal analgesia is widely used to achieve improved benefit-to-risk ratios in clinic. Drug-drug salts are extensively researched to optimize the physicochemical properties of active pharmaceutical ingredients (APIs) and achieve clinical benefits compared with individual APIs or their combination. New drug-drug salt crystals metformin-ibuprofen (MET-IBU) and metformin-naproxen (MET-NAP) were prepared from metformin (MET) and two poorly water-soluble anti-inflammatory drugs (IBU and NAP) by the solvent evaporation method. The structures of these crystals were confirmed by single crystal and powder X-ray diffraction, Hirshfeld surface, Fourier transform infrared spectroscopy and thermal analysis. Both MET-IBU and MET-NAP showed significantly improved solubility and intrinsic dissolution rate than the pure IBU or NAP. The stability test indicated that MET-IBU and MET-NAP have excellent physical stability under stressing test (10 days) and accelerated conditions (3 months). Moreover, isobolographic analysis suggested that MET-IBU and MET-NAP exerted potent and synergistic antinociceptive effects in λ-Carrageenan-induced inflammatory pain in mice, and both of them had an advantage in rapid pain relief. These results demonstrated the potential of MET-IBU and MET-NAP to achieve synergistic antinociceptive effects by developing drug-drug salt crystals.

Discovery of Dehydroabietylamine Derivatives as Antibacterial and Antifungal Agents

A diverse array of biologically active derivatives was derived by modifying the chemically active sites of dehydroabietylamine. Herein, we describe the synthesis of a new series of C-19-arylated dehydroabietylamine derivatives using a palladium-catalyzed C(sp3)-H activation reaction. Five analogues (3b, 3d, 3h, 3n, and 4a) exhibited antibacterial activity against Escherichia coli. Compound 4a exhibited strong inhibitory activity against DNA Topo II and Topo IV. Molecular docking modeling indicated that it can bind effectively to the target through interactions with amino acid residues. The synthesized compounds were tested in vitro for their antifungal activity against six common phytopathogenic fungi. The mechanism of action of compound 4c against Rhizoctorzia solani was investigated, revealing that it disrupts the morphology of the mycelium and enhances cell membrane permeability.

Syntheses and high selective cytotoxicity of dehydroabietylamine C-ring nitration derivatives

To find more effective anticancer agents, a series of novel dehydroabietylamine (DA) derivatives were synthesized, focusing on C-ring nitro modifications and C-18 imide introduction. Their cytotoxic activities against human tumor cell line HeLa (cervix), MCF-7 (breast), A549 (lung), HepG2 (liver), and nonmalignant cell line HUVEC (umbilical vein) in vitro were screened. The C-18 imide heterocyclic compounds 1, 2, and C-ring 14-nitro substituted 14 exhibited moderate to good cytotoxic activities and significant selectivity towards malignant cell lines. More importantly, they were significantly less cytotoxic to nonmalignant cells (HUVEC) than the parent compound and positive control doxorubicin hydrochloride (DOX). Meantime the mechanism of cytotoxicity of DA derivatives was studied. Annexin V-FITC/PI double-staining analysis suggested that cytotoxicity of compounds 2 and 14 was associated with early apoptosis induction. The interaction between compounds and DNA (herring sperm DNA) was studied using absorption spectral analysis and ethidium bromide (EB) fluorescence displacement experiments, the results exhibited that the binding of the compound to DNA was in the intercalative mode. The structure-activity relationship discussion implied that introduction of the nitro-group, especially the 14-nitro group, can significantly improve the cytotoxicity of dehydroabietylimide compounds. The relatively high cytotoxicity and significant high selectivity of compounds 2 and 14 indicated that they were particularly noteworthy. NO released amounts indicated that the amounts of NO released by the compounds bearing nitro-group were quite well associated positive correlation with their cytotoxic activity, which provide a new strategy for structure design of DA anticancer agents in the future.

Palladium-catalyzed cascade Heck-type cyclization and reductive aminocarbonylation for the synthesis of functionalized amides

A palladium-catalyzed Heck/carbonylative cyclization process has been explored for the synthesis of functionalized amides. By using nitroarenes as readily accessible nitrogen sources, a variety of amide products were obtained in moderate to excellent yields with good functional group compatibility. Furthermore, a late-stage modification of a natural molecule is also achieved by this protocol.

Recent development of imidazole derivatives as potential anticancer agents

Cancer, one of the key health problems globally, is a group of related diseases that share a number of characteristics primarily the uncontrolled growth and invasive to surrounding tissues. Chemotherapy is one of the ways for the treatment of cancer which uses one or more anticancer agents as per chemotherapy regimen. Limitations of most anticancer drugs due to a variety of reasons such as serious side effects, drug resistance, lack of sensitivity and efficacy etc. generate the necessity towards the designing of novel anticancer lead molecules. In this regard, the synthesis of biologically active heterocyclic molecules is an appealing research area. Among heterocyclic compounds, nitrogen containing heterocyclic molecules has fascinated tremendous consideration due to broad range of pharmaceutical activity. Imidazoles, extensively present in natural products as well as synthetic molecules, have two nitrogen atoms, and are five membered heterocyclic rings. Because of their countless physiological and pharmacological characteristics, medicinal chemists are enthused to design and synthesize new imidazole derivatives with improved pharmacodynamic and pharmacokinetic properties. The aim of this present chapter is to discuss the synthesis, chemistry, pharmacological activity, and scope of imidazole-based molecules in anticancer drug development. Finally, we have discussed the current challenges and future perspectives of imidazole-based derivatives in anticancer drug development.

Imidazole as a Promising Medicinal Scaffold: Current Status and Future Direction

Various imidazole-containing compounds have been tested for their medical usefulness in clinical trials for several disease conditions. The rapid expansion of imidazole-based medicinal chemistry suggests the promising and potential therapeutic values of imidazole-derived compounds for treating incurable diseases. Imidazole core scaffold contains three carbon atoms, and two nitrogen with electronic-rich characteristics that are responsible for readily binding with a variety of enzymes, proteins, and receptors compared to the other heterocyclic rings. Herein, we provide a thorough overview of the current research status of imidazole-based compounds with a wide variety of biological activities including anti-cancer, anti-microbial, anti-inflammatory and their potential mechanisms including topoisomerase IIR catalytic inhibition, focal adhesion kinase (FAK) inhibition, c-MYC G-quadruplex DNA stabilization, and aurora kinase inhibition. Additionally, a great interest was reported in the discovery of novel imidazole compounds with anti-microbial properties that break DNA double-strand helix and inhibit protein kinase. Moreover, anti-inflammatory mechanisms of imidazole derivatives include inhibition of COX-2 enzyme, inhibit neutrophils degranulation, and generation of reactive oxygen species. This systemic review helps to design and discover more potent and efficacious imidazole compounds based on the reported derivatives, their ADME profiles, and bioavailability scores that together aid to advance this class of compounds.

Imidazoles as Potential Anticancer Agents: An Update on Recent Studies

Nitrogen-containing heterocyclic rings are common structural components of marketed drugs. Among these heterocycles, imidazole/fused imidazole rings are present in a wide range of bioactive compounds. The unique properties of such structures, including high polarity and the ability to participate in hydrogen bonding and coordination chemistry, allow them to interact with a wide range of biomolecules, and imidazole-/fused imidazole-containing compounds are reported to have a broad spectrum of biological activities. This review summarizes recent reports of imidazole/fused imidazole derivatives as anticancer agents appearing in the peer-reviewed literature from 2018 through 2020. Such molecules have been shown to modulate various targets, including microtubules, tyrosine and serine-threonine kinases, histone deacetylases, p53-Murine Double Minute 2 (MDM2) protein, poly (ADP-ribose) polymerase (PARP), G-quadraplexes, and other targets. Imidazole-containing compounds that display anticancer activity by unknown/undefined mechanisms are also described, as well as key features of structure-activity relationships. This review is intended to provide an overview of recent advances in imidazole-based anticancer drug discovery and development, as well as inspire the design and synthesis of new anticancer molecules.

BioAIEgens derived from rosin: how does molecular motion affect their photophysical processes in solid state?

The exploration of artificial luminogens with bright emission has been fully developed with the advancement of synthetic chemistry. However, many of them face problems like weakened emission in the aggregated state as well as poor renewability and sustainability. Therefore, the development of renewable and sustainable luminogens with anti-quenching function in the solid state, as well as to unveil the key factors that influence their luminescence behavior become highly significant. Herein, a new class of natural rosin-derived luminogens with aggregation-induced emission property (AIEgens) have been facilely obtained with good biocompatibility and targeted organelle imaging capability as well as photochromic behavior in the solid state. Mechanistic study indicates that the introduction of the alicyclic moiety helps suppress the excited-state molecular motion to enhance the solid-state emission. The current work fundamentally elucidates the role of alicyclic moiety in luminogen design and practically demonstrates a new source to large-scalely obtain biocompatible AIEgens.

Synthesis and high antiproliferative activity of dehydroabietylamine pyridine derivatives in vitro and in vivo

Several bioactive dehydroabietylamine Schiff-bases (L1-L4), amides (L5-L11) and complex CuL3(NO3)2, Cu(L5)3, Co(L6)2Cl2 had been synthesized successfully for developing more efficient but lower toxic antiproliferative compounds. Their antiproliferative activities to Hela (cervix), HepG2 (liver), MCF-7 (breast), A549 (lung) and HUVEC (umbilical vein, normal cell) were investigated in vitro. The toxicity of all compounds was less than dehydroabietylamine (L0). For HepG2 cells, L1, L2 and L3 had higher anti-HepG2 activity, especially L1 (0.52 µM) had highest anti-HepG2 activity but low toxicity. For MCF-7 cells, L1, L2, L3 and L4 had higher anti-MCF-7 activity, especially L3(0.49 µM) had highest anti-MCF-7 activity but low toxicity. For A549 cells, L2 and L3 had higher anti-A549 activity. Furthermore, L1 and L3 may be the great promise antiproliferative drugs with nontoxic side effects, due to the high anti-HepG2 and anti-MCF-7 inhibition rate in vivo, 65% and 61%, respectively. L1, L2 and L3 could induce apoptosis through intercalating into DNA.

Synthesis of novel, DNA binding heterocyclic dehydroabietylamine derivatives as potential antiproliferative and apoptosis-inducing agents

Several dehydroabietylamine derivatives containing heterocyclic moieties such as thiophene and pyrazine ring were successfully synthesized. The antiproliferative activities of these thiophene-based Schiff-bases, thiophene amides, and pyrazine amides were investigated in vitro against Hela (cervix), MCF-7 (breast), A549 (lung), HepG2 (liver), and HUVEC (umbilical vein) cells by MTT assay. The toxicity of L1-L10 (IC50 = 5.92- >100 μM) was lower than L0 (1.27 μM) and DOX (4.40 μM) in every case. Compound L1 had higher anti-HepG2 (0.66 μM), anti-MCF-7 (5.33 μM), and anti-A549 (2.11 μM) and compound L3 had higher anti-HepG2 (1.63 μM) and anti-MCF-7 (2.65 μM) activities. Both of these compounds were recognized with high efficiency in apoptosis induction in HepG2 cells and intercalated binding modes with DNA. Moreover, with average IC50 values of 0.66 and 5.98 μM, L1 was nine times more effective at suppressing cultured HepG2 cells viability than normal cells (SI = 9). The relative tumor proliferation rate (T/C) was 38.6%, the tumor inhibition rate was up to 61.2%, which indicated that L1 had no significant toxicity but high anti-HepG2 activity in vivo. Thus, it may be a potential antiproliferation drug with nontoxic side effects.

Synthesis, antitumor and DNA cleavage activities of a novel class of dehydroabietylamine derivatives

Previous studies have reported higher biological activity of dehydrorosinamine derivatives. In order to further synthesize novel compounds with higher biological activity, a series of novel compounds containing benzo-azepine structures were synthesized from dehydroabietylamine in good yields in this study. The structures of synthesized compounds were identified by infra red (IR), ¹H-NMR, ¹³C-NMR, and mass spectra (MS) analysis. The antitumor activities of the target compounds against L02 and HepG2 cells were studied. Furthermore, the dehydroabietylamine derivatives were studied on plasmid DNA cleavage activities. The results showed that the synthesized target compound exhibit antitumor and DNA cleavage activities against plasmid DNA (Escherichia coli). Our results further demonstrate the relationship between the chemical structure and biological function of the synthesized compounds.

New chalcone-type compounds and 2-pyrazoline derivatives: synthesis and caspase-dependent anticancer activity

Aim: There is a continuous and urgent need for new anticancer agents with novel structures and target selectivity. Methods & results: The anticancer activity of the prepared compounds was assessed against human lung (A549) and stomach (AGS) cancer cell lines and evaluated in the noncancer human lung fibroblast (MRC-5) cell line. 2-Pyrazolines were devoid of toxicity in all cell lines used, chalcones bearing a β-(benz)imidazole moiety being toxic toward AGS cell line. Mechanistic studies showed that these compounds trigger loss of cell viability and mitochondrial membrane potential, while eliciting morphological traits compatible with regulated cell death, which was ultimately shown to derive from caspase activation, specifically caspase-3. Conclusion: Chalcones 1-3 have been identified as new and promising anticancer agents toward the AGS cell line.