Curcuminoid Chalcones: Synthesis and Biological Activity against the Human Colon Carcinoma (Caco-2) Cell Line.

BACKGROUND: There are many current scientific reports on the synthesis of various derivatives modelled on the structure of known small-molecular and natural bioactive compounds. Curcuminoid chalcones are an innovative class of compounds with significant therapeutic potential against various diseases and they perfectly fit into the current trends in the search for new biologically active substances. AIM: The aim of this study was to design and synthesise a series of curcuminoid chalcones. OBJECTIVE: The objective of this scientific paper was to synthesise twelve curcuminoid chalcones and confirm their structures using spectral methods. Additionally, the biological activity of three of the synthesised compounds was evaluated using various assays, and their anticancer properties and toxicity were studied. METHODS: The proposed derivatives were obtained via the Claisen-Schmidt reaction of selected acetophenones and aldehydes in various conditions using both classical methods: the solutions and solvent-free microwave (MW) or ultrasound (US) variants. The most optimal synthetic method for the selected curcuminoid chalcones was the classical Claisen-Schmidt condensation in an alkaline (NaOH) medium. Spectral methods were used to confirm the structures of the compounds. The resazurin reduction assay, caspase-3 activity assay, and RT-qPCR method were performed, followed by measurements of the intracellular reactive oxygen species (ROS) level and the lactate dehydrogenase (LDH) release level. RESULTS: Twelve designed curcuminoid chalcones were successfully synthesized and structurally confirmed by NMR, MS, and IR spectroscopy. Examination of the anticancer activity was carried out for the three most interesting chalcone products. CONCLUSION: The results suggested that compound 3a increased the metabolism and/or proliferation of the human colon carcinoma (Caco-2) cell line, while compounds 3b and 3f showed significant toxicity against the Caco-2 cell line. Overall, the preliminary results suggested that compound 3b exhibited the most favorable anticancer activity.

Curcuminoid Chalcones: Synthesis, Stability, and New Neuroprotective and Sonosensitising Activities.

The primary purpose of this work was to design and obtain a series of curcuminoid chalcone-NSAID hybrid derivatives. The ester-type hybrid compounds with ibuprofen (i), ketoprofen (ii), and naproxen (iii) were obtained in two ways, using the Claisen-Schmidt reaction and the Steglich esterification reaction. The designed molecules were successfully synthesised, and FT-IR, MS, and NMR spectroscopy confirmed their structures. Moreover, the cytotoxic effect of the sonodynamic therapy and the anti-inflammatory, antioxidant, and anticholinergic properties of some curcuminoid chalcones and curcuminoid chalcones hybrids were evaluated. The curcuminoid chalcone derivatives showed promising neuroprotective activity as sonosensitisers for sonodynamic therapy in the studied cell lines. Additionally, the stability of the ester-type hybrid compounds with promising activity was determined. The RP-HPLC method was used to observe the degradation of the tested compounds. Studies have shown that structural isomers of ester-type hybrid compounds (3ai, 3bi) are characterised by a similar susceptibility to degradation factors, i.e., they are extremely unstable in alkaline environments, very unstable in acidic environments, unstable in neutral environments, practically stable in oxidising environments, and photolabile in solutions and in the solid phase. These compounds maintain adequate stability in environment at pH 1.2 and 6.8, which may make them good candidates for developing formulations for oral administration.

Curcumin-Triterpene Type Hybrid as Effective Sonosensitizers for Sonodynamic Therapy in Oral Squamous Cell Carcinoma.

Sonodynamic therapy (SDT) is a non-invasive therapeutic modality in cancer treatment that combines low-intensity ultrasound (US) and sonosensitizers. Tumor cells are destroyed through the synergistic effects of ultrasound and a chemical sonosensitizer. This study focused on the synthesis and in vitro evaluation of the sonodynamic effect of natural curcumin, triterpene oleanolic acid, and their semi-synthetic derivatives on tongue cancer SCC-25 and hypopharyngeal FaDu cell lines. The combination of the tested compounds with sonication showed a synergistic increase in cytotoxicity. In the group of oleanolic acid derivatives, oleanoyl hydrogen succinate (6) showed the strongest cytotoxic effect both in the SCC-25 and FaDu cell lines. Comparing curcumin (4) and its pyrazole derivative (5), curcumin showed a better cytotoxic effect on SCC-25 cells, while curcumin pyrazole was more potent on FaDu cells. The highest sonotherapeutic activity, compared to its individual components, was demonstrated by a structural linker mode hybrid containing both curcumin pyrazole-oleanoyl hydrogen succinate units within one complex molecule (7). This study can be beneficial in the context of new perspectives in the search for effective sonosensitizers among derivatives of natural organic compounds.

Synthesis, Cytotoxicity and Molecular Docking of New Hybrid Compounds by Combination of Curcumin with Oleanolic Acid.

Curcumin and oleanolic acid are natural compounds with high potential in medicinal chemistry. These products have been widely studied for their pharmacological properties and have been structurally modified to improve their bioavailability and therapeutic value. In the present study, we discuss how these compounds are utilized to develop bioactive hybrid compounds that are intended to target cancer cells. Using a bifunctional linker, succinic acid, to combine curcumin and triterpenoic oleanolic acid, several hybrid compounds were prepared. Their cytotoxicity against different cancer cell lines was evaluated and compared with the activity of curcumin (the IC50 value (24 h), for MCF7, HeLaWT and HT-29 cancer cells for KS5, KS6 and KS8 compounds was in the range of 20.6-94.4 µM, in comparison to curcumin 15.6-57.2 µM). Additionally, in silico studies were also performed. The computations determined the activity of the tested compounds towards proteins selected due to their similar binding modes and the nature of hydrogen bonds formed within the cavity of ligand-protein complexes. Overall, the curcumin-triterpene hybrids represent an important class of compounds for the development of effective anticancer agents also without the diketone moiety in the curcumin molecule. Moreover, some structural modifications in keto-enol moiety have led to obtaining more information about different chemical and biological activities. Results obtained may be of interest for further research into combinations of curcumin and oleanolic acid derivatives.

Structure and Activity of Pentacyclic Triterpenes Codrugs. A Review.

Triterpenes are a wide and important group of compounds that have several promising pharmacological properties, such as hepatoprotective, anti-inflammatory, anti-HIV, antioxidant, or anticancer activities. Such potent substances can be successfully incorporated in more complex chemical systems e.g. codrugs or pro-drugs that have a better pharmacological profile. The codrug is connected with a drug formation pathway to chemically cohere at least two drug molecules to improve positive therapeutic efficiency or decrease side effects. The codrug can be cleaved in the organism to generate effective compounds previously used as substrates. This article presents an overview of codrugs that consist of pentacyclic triterpene moiety that is chosen as a basic codrug moiety due to their wide range of vital activities and another drug molecule fragment. It was found that triterpenoid codrugs are characterized by a wide range of biological activities. However, most of them have anticancer potency.

Microwave (MW), Ultrasound (US) and Combined Synergic MW-US Strategies for Rapid Functionalization of Pharmaceutical Use Phenols.

Increasingly stringent regulations aimed at protection of the natural environment have stimulated the search for new synthetic methodologies in organic and medicinal chemistry having no or minimum harmful effect. An interesting approach is the use of alternative activation factors, microwaves (MW) or ultrasounds (US) and also their cross-combination, which has been tested in the fast and efficient creation of new structures. At present, an easy and green hybrid strategy ("Lego" chemistry) is generally recommended for the design of new substances from different chemistry building blocks. Often, selected biologically active components with specific chemical reactivities are integrated by a suitably designed homo- or heterodifunctional linker that modifies the functionality of the starting structure, allowing easy covalent linkage to another molecule. In this study, a fast introduction of heterodifunctional halogenoacidic linker to selected mono-, di- and triphenolic active substances, allowing their functionalization, was investigated. Nucleophilic substitution reaction was chosen to produce final ethers with the reactive carboxylic group from phenols. The functionalization was performed using various green factors initiating and supporting the chemical reactions (MW, US, MW-US). The benefits of the three green supporting methods and different conditions of reactions were analyzed and compared with the results of the reaction performed by conventional methods.

Multidirectional Efficacy of Biologically Active Nitro Compounds Included in Medicines.

The current concept in searching for new bioactive products, including mainly original active substances with potential application in pharmacy and medicine, is based on compounds with a previously determined structure, well-known properties, and biological activity profile. Nowadays, many commonly used drugs originated from natural sources. Moreover, some natural materials have become the source of leading structures for processing further chemical modifications. Many organic compounds with great therapeutic significance have the nitro group in their structure. Very often, nitro compounds are active substances in many well-known preparations belonging to different groups of medicines that are classified according to their pharmacological potencies. Moreover, the nitro group is part of the chemical structure of veterinary drugs. In this review, we describe many bioactive substances with the nitro group, divided into ten categories, including substances with exciting activity and that are currently undergoing clinical trials.

Molecular Consortia-Various Structural and Synthetic Concepts for More Effective Therapeutics Synthesis.

The design and discovery of novel drug candidates are the initial and most probably the crucial steps in the drug development process. One of the tasks of medicinal chemistry is to produce new molecules that have a desired biological effect. However, even today the search for new pharmaceuticals is a very complicated process that is hard to rationalize. Literature provides many scientific reports on future prospects of design of potentially useful drugs. Many trends have been proposed for the design of new drugs containing different structures (dimers, heterodimers, heteromers, adducts, associates, complexes, biooligomers, dendrimers, dual-, bivalent-, multifunction drugs and codrugs, identical or non-identical twin drugs, mixed or combo drugs, supramolecular particles and various nanoindividuals. Recently much attention has been paid to different strategies of molecular hybridization. In this paper, various molecular combinations were described e.g., drug-drug or drug-non-drug combinations which are expressed in a schematic multi-factor form called a molecular matrix, consisting of four factors: association mode, connection method, and the number of elements and linkers. One of the most popular trends is to create small-small molecule combinations such as different hybrids, codrugs, drug-drug conjugates (DDCs) and small-large molecule combinations such as antibody-drug conjugates (ADCs), polymer-drug conjugates (PDCs) or different prodrugs and macromolecular therapeutics. A review of the structural possibilities of active framework combinations indicates that a wide range of potentially effective novel-type compounds can be formed. What is particularly important is that new therapeutics can be obtained in fast, efficient, and selective methods using current trends in chemical synthesis and the design of drugs such as the "Lego" concept or rational green approach.

Hybrid Compounds Strategy in the Synthesis of Oleanolic Acid Skeleton-NSAID Derivatives.

The current study focuses on the synthesis of several hybrid individuals combining a natural oleanolic acid skeleton and synthetic nonsteroidal anti-inflammatory drug moieties (NSAIDs). It studied structural modifications of the oleanolic acid structure by use of the direct reactivity of hydroxyl or hydroxyimino groups at position C-3 of the triterpenoid skeleton with the carboxylic function of anti-inflammatory drugs leading to new perspective compounds with high potential pharmacological activities. Novel ester- and iminoester-type derivatives of oleanolic unit with the different NSAIDs, such as ibuprofen, aspirin, naproxen, and ketoprofen, were obtained and characterized. Moreover, preliminary research of compounds obtaining structure stability under acidic conditions was examined and the PASS method of prediction of activity spectra for substances was used to estimate the potential biological activity of these compounds.

Synthesis of some N-substituted nitroimidazole derivatives as potential antioxidant and antifungal agents.

Some new nitroimidazole derivatives have been synthesized by treating 4,5-dinitro- and 2-methyl-4,5-dinitroimidazoles with epoxypropane, epichlorohydrin or phenacyl bromide in alkylation reactions. The nitro group in N-substituted 4,5-dinitro- and 2-methyl-4,5-dinitroimidazoles has been replaced with primary and secondary amines to afford 4-amino-5-nitroimidazole derivatives. Some of the compounds have been tested for their antioxidant and antifungal properties against fungi species acting on timber. Nearly all of them have shown significant antioxidant activity in comparison with that of tocopherol, which is used as a reference substance. Two compounds from those tested have revealed very strong fungistatic activity against Sclerophoma pityophila.

Synthesis of 2,3-dihydro-7-nitroimidazo[5,1-b]oxazoles as potential tuberculostatic agents.

A series of 2,3-dihydro-7-nitroimidazo[5,1-b]oxazoles has been prepared in one-pot reaction. The proposed new method of their synthesis requires a treatment of 4,5-dinitroimidazole or 2-methyl-4,5-dinitroimidazole with oxiranes. Some of the obtained compounds have been tested in vitro for antimycobacterial activity and the spatial structure of them has been also discussed.