Synthesis of novel benzofurocoumarin analogues and their anti-proliferative effect on human cancer cell lines

Coumarin as an Elite Scaffold in Anti-Breast Cancer Drug Development: Design Strategies, Mechanistic Insights, and Structure-Activity Relationships

Breast cancer is the most common cancer among women. Currently, it poses a significant threat to the healthcare system due to the emerging resistance and toxicity of available drug candidates in clinical practice, thus generating an urgent need for the development of new potent and safer anti-breast cancer drug candidates. Coumarin (chromone-2-one) is an elite ring system widely distributed among natural products and possesses a broad range of pharmacological properties. The unique distribution and pharmacological efficacy of coumarins attract natural product hunters, resulting in the identification of numerous natural coumarins from different natural sources in the last three decades, especially those with anti-breast cancer properties. Inspired by this, numerous synthetic derivatives based on coumarins have been developed by medicinal chemists all around the globe, showing promising anti-breast cancer efficacy. This review is primarily focused on the development of coumarin-inspired anti-breast cancer agents in the last three decades, especially highlighting design strategies, mechanistic insights, and their structure-activity relationship. Natural coumarins having anti-breast cancer efficacy are also briefly highlighted. This review will act as a guideline for researchers and medicinal chemists in designing optimum coumarin-based potent and safer anti-breast cancer agents.

Application of the Meerwein reaction of 1,4-benzoquinone to a metal-free synthesis of benzofuropyridine analogues

Several new heterocyclic systems based on a hydroxybenzofuro[2,3-b]pyridine building block were prepared. This benzofuropyridine is easily available from the Meerwein reaction of benzoquinone and a heterocyclic diazonium salt, followed by reduction and cyclization. Electrophilic substitution and further condensations give polycyclic systems, including oxazolo- and chromeno-fused analogues.

Application of Amino Acids in the Structural Modification of Natural Products: A Review

Natural products and their derivatives are important sources for drug discovery; however, they usually have poor solubility and low activity and require structural modification. Amino acids are highly soluble in water and have a wide range of activities. The introduction of amino acids into natural products is expected to improve the performance of these products and minimize their adverse effects. Therefore, this review summarizes the application of amino acids in the structural modification of natural products and provides a theoretical basis for the structural modification of natural products in the future. The articles were divided into six types based on the backbone structures of the natural products, and the related applications of amino acids in the structural modification of natural products were discussed in detail.

Synthesis of Coumarin Derivatives as Versatile Scaffolds for GSK-3β Enzyme Inhibition

BACKGROUND

Glycogen synthase kinase-3 (GSK-3) is involved in the phosphorylation and inactivation of glycogen synthase. GSK-3 inhibitors have been associated with a variety of diseases, including Alzheimer´s disease (AD), diabetes type II, neurologic disorders, and cancer. The inhibition of GSK-3β isoforms is likely to represent an effective strategy against AD.

OBJECTIVE

The present work aimed to design and synthesize coumarin derivatives to explore their potential as GSK-3β kinase inhibitors.

METHODS

The through different synthetic methods were used to prepare coumarin derivatives. The GSK-3β activity was measured through the ADP-Glo™ Kinase Assay, which quantifies the kinasedependent enzymatic production of ADP from ATP, using a coupled-luminescence-based reaction. A docking study was performed by using the crystallographic structure of the staurosporine/GSK-3β complex [Protein Data Bank (PDB) code: 1Q3D].

RESULTS

The eleven coumarin derivatives were obtained and evaluated as potential GSK-3β inhibitors. Additionally, in silico studies were performed. The results revealed that the compounds 5c, 5d, and 6b inhibited GSK-3β enzymatic activity by 38.97-49.62% at 1 mM. The other coumarin derivatives were tested at 1 mM, 1 µM, and 1 nM concentrations and were shown to be inhibitor candidates, with significant IC50 (1.224-6.875 µM) values, except for compound 7c (IC50 = 10.809 µM). Docking simulations showed polar interactions between compound 5b and Lys85 and Ser203, clarifying the mechanism of the most potent activity.

CONCLUSION

The coumarin derivatives 3a and 5b, developed in this study, showed remarkable activity as GSK-3β inhibitors.

Furanocoumarins in anticancer therapy - For and against

Furanocoumarins are a class of natural compounds produced by several plants, including those consumed by humans. They have been used medicinally in eastern countries for ages. Given the growing body of evidence about their anticancer potential and observations that naturally occurring compounds potentiate the antitumor activity of chemotherapeutics, more attention is paid to elucidation of the nature of furanocoumarins and the possibility of using thereof in practice. The general mechanism by which furanocoumarins eliminate cancer cells is based on cell cycle blockage and initiation of programmed death like apoptosis or autophagy. The precise molecular mechanism of such an action depends on the chemical structure of furanocoumarins, which is based on the furan ring attached to the coumarin backbone in a linear or angular form as well as the type, location, and number of the substituents attached. The review summarizes the current evidence of the antitumor properties of linear and angular furanocoumarins with special emphasis on the molecular mechanism of elimination of cancer cells via apoptosis and autophagy. Negative aspects of the use of coumarins in anticancer therapy will be also discussed especially in the context of their phototoxicity and potential cancerogenic effect.

Hesperidin exhibits in vitro and in vivo antitumor effects in human osteosarcoma MG-63 cells and xenograft mice models via inhibition of cell migration and invasion, cell cycle arrest and induction of mitochondrial-mediated apoptosis

The objective of the present study was to investigate the anticancer properties of hesperidin against human osteosarcoma MG-63 cells. Its effects on apoptosis, cell migration, cell invasion and cell cycle arrest, and its effects on tumor volume and weight were also evaluated in the present study. MTS assay was used to study the cytotoxic effects of the compound on cell viability. Effects on apoptosis and cell cycle arrest were evaluated by flow cytometry. In vitro wound healing assay and Matrigel assay were performed to study the effects of hesperidin on cell migration and cell invasion, respectively. Hesperidin exerted dose-dependent and time-dependent growth inhibitory effects on cervical cancer cells with IC50 values of 33.5, 23.8 and 17.6 µM, respectively, at 24, 48 and 72 h time intervals. Hesperidin led to early and late apoptosis induction in these cells. Hesperidin-treated cells also led to G2/M phase cell cycle arrest, which exhibited strong dose-dependence. Hesperidin treatment also led to inhibition of cell migration and invasion.

7,8-Dihydroxy-3-(4-nitrophenyl)coumarin induces cell death via reactive oxygen species-independent S-phase cell arrest

We herein report the synthesis and in vitro cytotoxicity of 3-arylcoumarin derivatives (6a-f and 7a-f) in human liver (HepG2), prostate (LNCap), and pancreatic (BxPC3) cancer cell lines. Among the tested compounds, 7,8-dihydroxy-3-(4-nitrophenyl) coumarin (7b) showed the highest cytotoxicity in the HepG2 cell line. The mechanism of cytotoxic action indicated that compound (7b) arrested HepG2 cells at the S phase of the cell cycle progression, induced loss of mitochondrial membrane potential, and caused reactive oxygen species (ROS)-independent cell death. The cell viability result of pretreated HepG2 cells with antioxidant N-acetylcysteine followed by compound (7b) treatment and the free radical scavenging activities of compound (7b) confirmed the ROS-independent cell death. These results demonstrate that compound (7b) could serve as a valuable template for the development of novel synthetic compounds as potential anticancer agents for hepatocellular carcinoma treatment.

Coumarin-Chalcone Hybrids as Peroxyl Radical Scavengers: Kinetics and Mechanisms

The primary antioxidant activity of coumarin-chalcone hybrids has been investigated using the density functional and the conventional transition state theories. Their peroxyl radical scavenging ability was studied in solvents of different polarity and taking into account different reaction mechanisms. It was found that the activity of the hybrids increases with the polarity of the environment and the number of phenolic sites. In addition, their peroxyl radical scavenging activity is larger than those of the corresponding nonhybrid coumarin and chalcone molecules. This finding is in line with previous experimental evidence. All the investigated molecules were found to react faster than Trolox with (•)OOH, regardless of the polarity of the environment. The role of deprotonation on the overall activity of the studied compounds was assessed. The rate constants and branching ratios for the reactions of all the studied compounds with (•)OOH are reported for the first time.

In vitro assessment of mutagenic and genotoxic effects of coumarin derivatives 6,7-dihydroxycoumarin and 4-methylesculetin

Coumarins are naturally occurring compounds, widely distributed throughout the plant kingdom (Plantae), and possess important pharmacological properties, including inhibition of oxidative stress. In this context, newly synthesized coumarin compounds are being produced due to their potent antioxidant activities. Therefore, the aim of the present study was to determine the in vitro cytotoxic, mutagenic, and genotoxic effects of 6,7-dihydroxycoumarin (6,7-HC) and 4-methylesculetin (4-ME) using the Salmonella/microsome test and in cultured human lymphocytes the comet assay and micronucleus test. The three coumarin derivatives concentrations evaluated in comet and MN assays were 2, 8, and 32 μg/mL, selected through a preliminary trypan blue-staining assay. In the Ames test, the 5 concentrations tested were 62.5, 125, 250, 500, and 750 μg/plate. Positive (methyl methane-sulfonate, MMS) and negative (dimethyl sulfoxide, DMSO) control groups were also included in the analysis. Our results showed that 4-ME induced greater cytotoxicity at high concentrations than 6,7-HC. In addition, both compounds were not mutagenic in the Ames test and not genotoxic or clastogenic/aneugenic in cultured human lymphocytes.

Novel benzopsoralen analogues: synthesis, biological activity and molecular docking studies

New benzopsoralen analogues were synthesized and their inhibitory effect on the growth of tumourtumour cell lines (MDA MB231 and TCC-SUP) was evaluated. The in vitro antitumour activity of the new benzopsoralen analogues was discussed in terms of structure-activity relationship. Molecular docking studies with human-CYP2A6 enzymes were also carried out with the synthesized compounds to evaluate the potential of these molecules to interact with the haem group of the enzymes. The results demonstrated that the compounds that are able to interact with the iron ion of the haem cofactor and at the same time with active site Asn297 are those that have better anti-proliferative activity.

Effects of psoralens as anti-tumoral agents in breast cancer cells

This review examines the biological properties of coumarins, widely distributed at the highest levels in the fruit, followed by the roots, stems and leaves, by considering their beneficial effects in the prevention of some diseases and as anti-cancer agents. These compounds are well known photosensitizing drugs which have been used as pharmaceuticals for a broad number of therapeutic applications requiring cell division inhibitors. Despite this, even in the absence of ultraviolet rays they are active. The current paper mainly focuses on the effects of psoralens on human breast cancer as they are able to influence many aspects of cell behavior, such as cell growth, survival and apoptosis. In addition, analytical and pharmacological data have demonstrated that psoralens antagonize some metabolizing enzymes, affect estrogen receptor stability and counteract cell invasiveness as well as cancer drug resistance. The scientific findings summarized highlight the pleiotropic functions of phytochemical drugs, given that recently their target signals and how these are modified in the cells have been identified. The encouraging results in this field suggest that multiple modulating strategies based on coumarin drugs in combination with canonical chemotherapeutic agents or radiotherapy could be a useful approach to address the treatment of many types of cancer.

Evaluation of the antioxidant capacity of synthesized coumarins

Coumarins are secondary metabolites that are widely distributed within the plant kingdom, some of which have been extensively studied for their antioxidant properties. The antioxidant activity of coumarins assayed in the present study was measured by different methods, namely the 1,1-diphenyl-2-picryl-hydrazyl (DPPH(•)) method, cyclic voltammetry and the antioxidant capacity against peroxyl radicals (ACAP) method. The 7,8-dihydroxy-4-methylcoumarin (LaSOM 78), 5-carboxy-7,8-dihydroxy-4-methylcoumarin (LaSOM 79), and 6,7-dihydroxycoumarin (Esculetin) compounds proved to be the most active, showing the highest capacity to deplete the DPPH radicals, the highest antioxidant capacity against peroxyl radicals, and the lowest values of potential oxidation.