Synthesis and Biological Evaluation of Curcumin Derivatives with Water-Soluble Groups as Potential Antitumor Agents: An in Vitro Investigation Using Tumor Cell Lines

Mild and Chemoselective Triethylsilane-Mediated Debenzylation for Phosphate Synthesis

The synthetic utility of tetrabenzyl pyrophosphate for achieving chemoselective phosphorylation of phenols, as well as primary, secondary, and tertiary alcohols, is reported here. Additionally, we introduce a rapid, mild, and chemoselective debenzylation procedure, enabling access to phosphates in the presence of redox sensitive groups. Finally, stoichiometrically controlled monodebenzylation provides a versatile platform for late-stage divergent synthesis of phosphodiester and phosphoramidate chemical libraries.

Synthesis of curcumin derivatives targeting androgen receptor for castration-resistant prostate cancer therapy

In this work, a series of curcumin derivatives (1a-1h, 2a-2g, and 3a-3c) were synthesized for the suppression of castration-resistant prostate cancer cells. All synthesized compounds were characterized by 1H NMR, 13C NMR, HRMS, and melting point. The in vitro cytotoxicity study shows that compounds 1a, 1e, 1f, 1h, 2g, 3a, and 3c display similar or enhanced cytotoxicity against 22Rv1 and C4-2 cells as compared to ASC-J9, other synthesized compounds display reduced cytotoxicity against 22Rv1 and C4-2 cells as compared to ASC-J9. Molecular docking simulation was performed to study the binding affinity and probable binding modes of the synthesized compounds with androgen receptor. The results show that all synthesized compounds exhibit higher cdocker interaction energies as compared to ASC-J9. Compounds 1h, 2g, and 3c not only show strong cytotoxicity against 22Rv1 and C4-2 cells but also exhibit high binding affinity with androgen receptor. In androgen receptor suppression study, compounds 1f and 2g show similar androgen receptor suppression effect as compared to ASC-J9 on C4-2 cells, compound 3c displays significantly enhanced AR suppression effect as compared to ASC-J9, 1f and 2g. Compounds 1a, 1e, 1f, 1h, 2g, 3a and 3c prepared in this work have significant potential for castration-resistant prostate cancer therapy.

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 favourable anticancer activity.

Novel Curcumin Analogue L6H4 in Treating Liver Fibrosis and Type 2 Diabetes

Purpose

The objective of this study was to evaluate the therapeutic efficacy of the curcumin analogue L6H4 in attenuating liver fibrosis and alleviating insulin resistance in streptozotocin-induced diabetic rats.

Methods

Male Sprague-Dawley rats were fed a high-fat diet to induce insulin resistance, followed by streptozotocin injection to induce diabetes. The rats were then treated with L6H4 for eight weeks. Body weight, metabolic parameters, liver function, and liver histopathology were evaluated. Immunohistochemistry was performed to assess the expression of TGF-β1, TIMP-2, and MMP-2 in liver tissues. Statistical analysis was conducted using one-way ANOVA and Spearman rank correlation test.

Results

L6H4 treatment effectively reversed the weight gain associated with a high-fat diet and improved metabolic parameters in diabetic rats. Liver function markers, such as ALT and AST, were reduced after L6H4 treatment. Histological analysis showed improved liver morphology and reduced fibrosis in L6H4-treated rats. Electron microscopy revealed improved ultrastructural features of hepatocytes. Immunohistochemistry demonstrated downregulation of TGF-β1 and TIMP-2 expression and restoration of MMP-2 expression in the liver tissue of L6H4-treated rats. Correlation analysis showed a significant positive correlation between TGF-β1 and TIMP-2 expression.

Conclusion

The findings suggest that L6H4 has therapeutic potential in attenuating liver fibrosis and alleviating insulin resistance in streptozotocin-induced diabetic rats. The hepatoprotective effect of L6H4 may be attributed to its anti-inflammatory properties and its ability to target molecules involved in fibrosis. Further research is warranted to explore the potential of L6H4 as a treatment option for nonalcoholic fatty liver disease and type 2 diabetes.

Studies on anti-colon cancer potential of nanoformulations of curcumin and succinylated curcumin in mannosylated chitosan

Colon cancer (CRC) is the second leading cause of death and the third most diagnosed cancer worldwide. Although curcumin (CUR) has demonstrated a potent anticancer activity, it is characterized by its poor solubility, low bioavailability, and instability. This study is a projection from a previous investigation where CUR and succinylated CUR (CUR.SA) were separately encapsulated in mannosylated-chitosan nanoparticles (CM-NPs) to form CUR-NPs and CUR.SA-NPs, respectively. Here, we aim to assess the anti-CRC activity of these two nanoformulations. Cytotoxicity studies using CCK-8 assay indicated that both CUR-NPs and CUR.SA-NPs have a dose and time-dependent toxicity towards CRC human cell-lines (HCT116 and SW480), and more cytotoxic compared to free CUR or CUR-SA in a time-dependent manner. A significant induction of early and late apoptosis in the CUR-NPs and CUR.SA-NPs treated CRC cell lines compared to untreated cells was observed. Western blotting analyses confirmed the induction of apoptosis through activation of Caspase signaling compared to untreated cells. Based on the physicochemical properties of CUR-NPs and CUR.SA-NPs along with the data from the in vitro studies, we may conclude these nanoparticle formulations hold very promising attributes, worthy of further investigations for its role in the management of CRC.

Recent advances of curcumin derivatives in breast cancer

Curcumin is a potential plant-derived drug for the treatment of breast cancer. Poor solubility and bioavailability are the main factors that limit its clinical application. Various structural modification strategies have been developed to improve the anti-breast cancer activity of curcumin. This review focuses on the difference of modification sites and heterocyclic/non-heterocyclic modifications to systematically summarize curcumin derivatives with better anti-breast cancer activity.

Curcumin and Derivatives in Nanoformulations with Therapeutic Potential on Colorectal Cancer

There is growing concern in the rise of colorectal cancer (CRC) cases globally, and with this rise is the presentation of drug resistance. Like other cancers, current treatment options are either invasive or manifest severe side effects. Thus, there is a move towards implementing safer treatment options. Curcumin (CUR), extracted from Curcuma longa, has received significant attention by scientists as possible alternative to chemotherapeutic agents. It is safe and effective against CRC and nontoxic in moderate concentrations. Crucially, it specifically modulates apoptotic effects on CRC. However, the use of CUR is limited by its low solubility and poor bioavailability in aqueous media. These limitations are surmountable through novel approaches, such as nanoencapsulation of CUR, which masks the physicochemical properties of CUR, thus potentiating its anti-CRC effects. Furthermore, chemical derivatization of CUR is another approach that can be used to address the above constraints. This review spans published work in the last two decades, with key findings employing either of the two approaches, in addition to a combined approach in managing CRC. The combined approach affords the possibility of better treatment outcomes but not widely investigated nor yet clinically implemented.

Photophysical Properties and Electronic Structure of Symmetrical Curcumin Analogues and Their BF2 Complexes, Including a Phenothiazine Substituted Derivative

Symmetrically substituted curcumin analogue compounds possess electron donor moieties at both ends of the conjugated systems; their difluoroboron complexes were synthesized, and their structures were fully characterized. A novel compound with enhanced photophysical properties bearing phenothiazine moieties is reported. The introduction of BF2 into the molecular structures resulted in bathochromic shifts both in the absorption and emission spectra, indicating that the π-conjugation was more extended than the one in the initial compounds. The solvatochromic effects were studied, which in case of the phenothiazinyl-curcumin BF2 complex was the most notable. Theoretical study of the investigated compounds was carried out using DFT and TD-DFT methods to evaluate the ground state geometries and vertical excitation energies.

Impact of curcumin on fatty acid metabolism

Free fatty acids (FFAs) and fatty acid synthesis (FAS) activity have significantly contributed to disease states such as insulin resistance, obesity, type 2 diabetes, myocardial infarction, blood pressure, and several types of cancer. Currently, several treatment options are available for patients with these conditions. Due to safety concerns, adverse effects, limited efficacy, and low tolerability associated with many medications, the identification of novel agents with less toxicity and a more favorable outcome is warranted. Curcumin is a phenolic compound derived from the turmeric plant with various biological activities, including anticarcinogenic, antioxidant, antiinflammatory, and hypolipidemic properties. PubMed, Scopus, and Web of Science were searched up to February 2020 for studies that demonstrated the efficacy and mechanisms of curcumin action on FFAs, FAS, and β-oxidation activity, as well as the desaturation system. Most of the evidence is in-vivo and in-vitro studies that demonstrate that curcumin possesses regulatory properties on FFAs levels through its effects on FAS and β-oxidation activity as well as desaturation system, which could improve insulin resistance, obesity, and other FFAs-related disorders. The present study provides a review of the existing in-vitro, in-vivo, and clinical evidence on the effect of curcumin on FFAs and FAS activity, β-oxidation, and desaturation system.

Curcuma longa L. helps macrophages to control opportunistic micro-organisms during host-microbe interactions

Aim: Plant products have been evaluated to control opportunistic micro-organisms, as well as fortify immune system cells. Thus, Curcuma longa L. (turmeric) extract was evaluated in interactions of murine macrophages (RAW 264.7) with Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans, in order to establish cooperation with defense cells. Materials & methods: Effects of minimal inhibitory concentrations (MIC) of the plant extract were analyzed on phagocytosis, cell viability of RAW 264.7 and production of inflammation-related molecules (IL-1β, TNF-α, IL-10 and NO). Results: The plant extract was cytocompatible and promoted significant reductions of micro-organisms, and synthesis of inflammation-related molecules, during interactions. Conclusion: C. longa L. extract showed significant antimicrobial response and cooperation with macrophages, by fighting bacteria and yeasts during host-microbe interactions.

Harnessing Mechanosensation in Next Generation Cardiovascular Tissue Engineering

The ability of the cells to sense mechanical cues is an integral component of ”social” cell behavior inside tissues with a complex architecture. Through ”mechanosensation” cells are in fact able to decrypt motion, geometries and physical information of surrounding cells and extracellular matrices by activating intracellular pathways converging onto gene expression circuitries controlling cell and tissue homeostasis. Additionally, only recently cell mechanosensation has been integrated systematically as a crucial element in tissue pathophysiology. In the present review, we highlight some of the current efforts to assess the relevance of mechanical sensing into pathology modeling and manufacturing criteria for a next generation of cardiovascular tissue implants.

Synthesis of a Novel Curcumin Derivative as a Potential Imaging Probe in Alzheimer's Disease Imaging

BACKGROUND

Curcumin has been of interest in the field of Alzheimer's disease. Early studies on transgenic mice showed promising results in the reduction of amyloid plaques.However, curcumin is very poorly soluble in aqueous solutions and not easily accessible to coupling as it contains only phenolic groups as potential coupling sites. For these reasons only few imaging studies using curcumin bound as an ester were performed and curcumin is mainly used as nutritional supplement.

METHODS

In the present study we produced an aminoethyl ether derivative of curcumin using a nucleophilic substitution reaction. This is a small modification and should not impact the properties of curcumin while introducing an easily accessible reactive amino group. This novel compound could be used to couple curcumin to other molecules using the standard methods of peptide synthesis. We studied the aminoethyl-curcumin compound and a tripeptide carrying this aminoethyl-curcumin and the fluorescent dye fluorescein (FITC-curcumin) in vitro on cell culture using confocal laser scanning microscopy and flow cytometry. Then these two substances were tested ex vivo on brain sections prepared from transgenic mice depicting Alzheimer-like β-amyloid plaques.

RESULTS

In the in vitro CLSM microscopy and flow cytometry experiments we found dot-like unspecific uptake and only slight cytotoxicity correlating with this uptake. As these measurements were optimized for the use of fluorescein as dye we found that the curcumin at 488nm fluorescence excitation was not strong enough to use it as a fluorescence marker in these applications. In the ex vivo sections CLSM experiments both the aminoethyl-curcumin and the FITC-curcumin peptide bound specifically to β- amyloid plaques.

CONCLUSION

In conclusion we successfully produced a novel curcumin derivative which could easily be coupled to other imaging or therapeutic molecules as a sensor for amyloid plaques.

An Update on the Pharmacological Usage of Curcumin: Has it Failed in the Drug Discovery Pipeline?

The pharmacological propensities of curcumin have been reported in a plethora of pre-clinical and clinical studies. However, innate attributes account for extremely low oral bioavailability which impedes its development as a therapeutic agent. Regardless, these drawbacks have not deterred researchers from optimizing its potentials. This review discussed the pharmacokinetic properties of curcumin relative to its outlook as a lead compound in drug discovery. Also, we highlighted therapeutic strategies that have expedited improvements in curcumin oral bioavailability and delivery to target sites over the years. Recent implementations of these strategies were also covered. More research efforts should be directed towards investigating the pharmacokinetic impacts of these novel curcumin formulations in human clinical studies since inter-species disparities could limit the accuracies of animal studies. We envisaged that integrative-clinical research would help determine 'actual' improvements in curcumin pharmacokinetics coupled with suitable administrative routes, optimal dosing, and drug-enzyme or drug-drug interactions. In addition, this could help determine formulations for achieving higher systemic exposure of parent curcumin thereby providing a strong impetus towards the development of curcumin as a drug candidate in disease treatment.

Development and Evaluation of Curcumin Liquid Crystal Systems for Cervical Cancer

Curcumin is a hydrophobic compound with good anti-proliferative, anti-oxidative, and anti-cancer properties but has poor bioavailability. Liquid crystals (LC) can accommodate both hydrophilic and hydrophobic drugs. The aim of this study was to formulate and evaluate a novel vaginal drug delivery system for cervical cancer using a curcumin LC system. The curcumin LC system was formulated using surfactant, glycerol, and water together with curcumin. Three types of surfactants were used to optimize the formulation, i.e., Tween 80, Cremphor EL, and Labrasol. The optimized formulations were subjected to physicochemical analysis, and their efficacy was evaluated in HeLa cells. The pH of the formulations was in the range of 3.91–4.39. Environmental scanning electron microscopy (ESEM) observations revealed spherical as well as hexagonal micelles. In vitro release of LC curcumin from vaginal simulated fluid (VSF, pH 4.5) showed a release from 20.47% to 87.25%. The IC50 of curcumin in HeLa cells was 22.5 μg/mL, while the IC25 and IC75 were 6.5 μg/mL and 35μg/mL, respectively. The cytotoxicity of the formulations was determined in comparison with liquid crystals without curcumin and pure curcumin by performing a t-test based on a significance level of p less than or equal to 0.05 (p ≤ 0.05). The curcumin LC system was able to release the required amount of drug and was effective against the cervical cancer cell line examined.

Curcumin and Its Derivatives as Potential Therapeutic Agents in Prostate, Colon and Breast Cancers

Cancer is a life-threatening disease and is the second leading cause of death around the world. The increasing threats of drug-resistant cancers indicate that there is an urgent need for the improvement or development of more effective anticancer agents. Curcumin, a phenolic compound originally derived from turmeric plant (Curcuma longa L. (Zingiberaceae family)) widely known as a spice and a coloring agent for food have been reported to possess notable anticancer activity by inhibiting the proliferation and metastasis, and enhancing cell cycle arrest or apoptosis in various cancer cells. In spite of all these benefits, the therapeutic application of curcumin in clinical medicine and its bioavailability are still limited due to its poor absorption and rapid metabolism. Structural modification of curcumin through the synthesis of curcumin-based derivatives is a potential approach to overcome the above limitations. Curcumin derivatives can overcome the disadvantages of curcumin while enhancing the overall efficacy and hindering drug resistance. This article reports a review of published curcumin derivatives and their enhanced anticancer activities.

Understanding Interactions of Curcumin with Lipid Bilayers: A Coarse-Grained Molecular Dynamics Study

The interactions of curcumin with various lipid bilayers (POPC, DOPC, oxidized POPC, and oxidized DOPC) and model biomembranes (symmetric bacteria and yeast plasma membranes, as well as asymmetric mammalian plasma membrane) are investigated. A nonlinear thinning effect of curcumin with respect to its concentration is demonstrated in PC membranes and in the yeast. Curcumin induces asymmetry to the symmetric yeast membranes but reduces the degree of asymmetry of the mammalian plasma membranes when the molecule is placed facing the outer leaflets. The molecule is found to diffuse through oxidized PC bilayers, POPC bilayers at a curcumin to lipid ratio C/L = 1/5, yeast membranes at C/L = 1/100, and the mammalian plasma membranes at C/L = 1/5 and when the molecule placed facing the outer leaflets. The results of this work demonstrate that the lipid type, the lipid distribution, and curcumin amount play a critical role in defining the interactions of curcumin with the lipids and their transport behavior through the bilayers.

Insights on the synthesis of asymmetric curcumin derivatives and their biological activities

Curcumin is a small organic molecule with pleiotropic biological activities. However, its multiple structural-pharmacokinetic challenges prevent its development into a clinical drug. Various structural modifications have been made to improve its drug profile. In this review, we focus on the methods adopted in the synthesis of asymmetric curcumin derivatives and their biological activities and forecast the future of this exciting class of compounds in the field of medicine.

New bis(hydroxymethyl) alkanoate curcuminoid derivatives exhibit activity against triple-negative breast cancer in vitro and in vivo

Novel bis(hydroxymethyl) alkanoate curcuminoid derivatives were designed, synthesized and screened for in vitro antiproliferative and in vivo antitumor activity. Selected new compound 9a and curcumin were further evaluated for inhibitory activity against ER⁺/PR⁺ breast cancer (MCF-7, T47D), HER 2⁺ breast cancer (SKBR3, BT474, and MDA-MB-457) and triple negative breast cancer (TNBC) (HS-578T, MDA-MB-157, and MDA-MB-468) cell lines. In addition, compound 9a was evaluated in the MDA-MB-231 xenograft nude mice model. Compound 9a exhibited greater inhibitory activity than curcumin against TNBC cells and also demonstrated significant inhibitory activity against doxorubicin-resistant MDA-MB-231 cells, with ten-fold higher potency than curcumin. Furthermore, when evaluated against the MDA-MB-231 xenograft nude mice model, compound 9a alone was ten-fold more potent than curcumin. Moreover, synergistic activity was observed when 9a was used in combination with doxorubicin against MDA-MB-231 breast cancer cells.

Curcumin inhibits lipolysis via suppression of ER stress in adipose tissue and prevents hepatic insulin resistance

Curcumin is natural polyphenol with beneficial effects on lipid and glucose metabolism and this study aimed to investigate the effects of curcumin on lipolysis and hepatic insulin resistance. Endoplasmic reticulum (ER) stress and lipolysis signaling in adipose and FFA influx, lipid deposits, and glucose production in liver were examined. Palmitate challenge and high-fat diet feeding evoked ER stress-associated lipolysis with cAMP accumulation in adipose tissue. Curcumin treatment inhibited adipose tissue ER stress by dephosphorylation of inositol-requiring enzyme 1α and eukaryotic initiation factor 2α and reduced cAMP accumulation by preserving phosphodiesterase 3B induction. Knockdown of mitogen-activated protein kinase α1/2α with siRNAs diminished such effects of curcumin. As a result from downregulation of cAMP, curcumin blocked protein kinase (PK)A/hormone-sensitive lipase lipolysis signaling, and thereby reduced glycerol and FFA release from adipose tissue. Curcumin reduced FFA influx into the liver by blocking FFA trafficking, and then prevented diacylglycerol deposits and PKCε translocation in the liver, resultantly improving insulin action in the suppression of hepatic gluconeogenesis. Curcumin decreased adipose lipolysis by attenuating ER stress through the cAMP/PKA pathway, reduced FFA influx into the liver by blocking FFA trafficking, and thereby improved insulin sensitivity to inhibit hepatic glucose production. These findings suggested a novel pathway of curcumin to prevent lipid deposits and insulin resistance in liver by beneficial regulation of adipose function.