Diarylpentanoids with antitumor activity: A critical review of structure-activity relationship studies

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.

Turmeric: from spice to cure. A review of the anti-cancer, radioprotective and anti-inflammatory effects of turmeric sourced compounds

Turmeric (Curcuma longa) has been extensively studied for its diverse pharmacological properties, including its potential role as an anticancer agent, antioxidant, and radioprotector. This review provides an overview of the chemical composition of turmeric, focusing on its main bioactive compounds, such as curcuminoids and volatile oils. Curcumin, the most abundant curcuminoid in turmeric, has been widely investigated for its various biological activities, including anti-inflammatory, antioxidant, and anticancer effects. Numerous in vitro and in vivo studies have demonstrated the ability of curcumin to modulate multiple signaling pathways involved in carcinogenesis, leading to inhibition of cancer cell proliferation, induction of apoptosis, and suppression of metastasis. Furthermore, curcumin has shown promising potential as a radioprotective agent by mitigating radiation-induced oxidative stress and DNA damage. Additionally, turmeric extracts containing curcuminoids have been reported to exhibit potent antioxidant activity, scavenging free radicals and protecting cells from oxidative damage. The multifaceted pharmacological properties of turmeric make it a promising candidate for the development of novel therapeutic strategies for cancer prevention and treatment, as well as for the management of oxidative stress-related disorders. However, further research is warranted to elucidate the underlying mechanisms of action and to evaluate the clinical efficacy and safety of turmeric and its bioactive constituents in cancer therapy and radioprotection. This review consolidates the most recent relevant data on turmeric's chemical composition and its therapeutic applications, providing a comprehensive overview of its potential in cancer prevention and treatment, as well as in radioprotection.

BP-M345 as a Basis for the Discovery of New Diarylpentanoids with Promising Antimitotic Activity

Recently, the diarylpentanoid BP-M345 (5) has been identified as a potent in vitro growth inhibitor of cancer cells, with a GI50 value between 0.17 and 0.45 µM, showing low toxicity in non-tumor cells. BP-M345 (5) promotes mitotic arrest by interfering with mitotic spindle assembly, leading to apoptotic cell death. Following on from our previous work, we designed and synthesized a library of BP-M345 (5) analogs and evaluated the cell growth inhibitory activity of three human cancer cell lines within this library in order to perform structure-activity relationship (SAR) studies and to obtain compounds with improved antimitotic effects. Four compounds (7, 9, 13, and 16) were active, and the growth inhibition effects of compounds 7, 13, and 16 were associated with a pronounced arrest in mitosis. These compounds exhibited a similar or even higher mitotic index than BP-M345 (5), with compound 13 displaying the highest antimitotic activity, associated with the interference with mitotic spindle dynamics, inducing spindle collapse and, consequently, prolonged mitotic arrest, culminating in massive cancer cell death by apoptosis.

Design, Synthesis, and Biological Evaluation of Water-Soluble Prodrugs of C5-Curcuminoid GO-Y030 Based on Reversible Thia-Michael Reaction

Although curcumin and its analogs exhibit anticancer activity, they are still not used as anticancer drugs because of their water insolubility and extremely poor bioavailability. This study describes the development of water-soluble prodrugs of GO-Y030, a potent antitumor C5-curcuminoid, in an attempt to enhance its bioavailability. These prodrugs release the parent compound via a retro-thia-Michael reaction. To endow sufficient hydrophilicity onto GO-Y030 via a single thia-Michael reaction of an aqueous entity, we used a modified glycoconjugate with a thiol group. The water-solubilizing motif was installed on GO-Y030 by the thia-Michael reaction of propargyl-polyethylene glycol (PEG)-thiol and subsequent click chemistry (CuAAC) reaction with 1-glycosyl azide. Turbidity measurements revealed a significantly improved water solubility of the prodrugs, demonstrating that disaccharide conjugates were completely dissolved in water at 100 µM. Their cytotoxicity was comparable to that of the parent compound GO-Y030, indicating the gradual in situ release of GO-Y030. The release of GO-Y030 from GO-Y199 via the retro-thia-Michael reaction was demonstrated through a degradation study in water. Our retro-thia-Michael reaction-based prodrug system can be used for targeting cancer cells.

Synthesis of alnustone-like diarylpentanoids via a 4 + 1 strategy and assessment of their potential anticancer activity

Twelve compounds with a 1,5-diaryl-1-penten-3-one structure were synthesized and their cytotoxic activities were evaluated. The 1,5-diaryl-1-penten-3-one compounds were obtained via in situ enaminations of 4-phenyl-2-butanone and 4-(4-hydroxyphenyl)-2-butanone in the presence of pyrrolidine-AcOH, followed by condensation with six different benzaldehydes. The synthesized compounds were tested for their cytotoxic activity against human glioblastoma (U87-MG), breast (MCF-7), and prostate (PC-3) cancer cell lines. Some of the novel compounds exhibited remarkable cytotoxic action, especially against MCF-7 cancer cells.

Structure-Activity Relationship Studies of Chalcones and Diarylpentanoids with Antitumor Activity: Potency and Selectivity Optimization

We previously reported that chalcone CM-M345 (1) and diarylpentanoid BP-C4 (2) induced p53-dependent growth inhibitory activity in human cancer cells. Herein, CM-M345 (1) and BP-C4 (2) analogues were designed and synthesized in order to obtain more potent and selective compounds. Compounds 16, 17, 19, 20, and 22-24 caused pronounced in vitro growth inhibitory activity in HCT116 cells (0.09 < GI50 < 3.10 μM). Chemical optimization of CM-M345 (1) led to the identification of compound 36 with increased selectivity for HCT116 cells expressing wild-type p53 compared to its p53-null isogenic derivative and low toxicity to non-tumor HFF-1 cells. The molecular modification of BP-C4 (2) resulted in the discovery of compound 16 with more pronounced antiproliferative activity and being selective for HCT116 cells with p53, as well as 17 with enhanced antiproliferative activity against HCT116 cells and low toxicity to non-tumor cells. Compound 16 behaved as an inhibitor of p53-MDM2 interaction, and compound 17 was shown to induce apoptosis, associated with an increase in cleaved PARP and decreased levels of the anti-apoptotic protein Bcl-2. In silico studies allowed us to predict the druglikeness and ADMET properties for 16 and 17. Docking and molecular dynamics studies predicted that 16 could bind stably to the MDM2 binding pocket.

Discovery of a New Chalcone-Trimethoxycinnamide Hybrid with Antimitotic Effect: Design, Synthesis, and Structure-Activity Relationship Studies

In this work, the design and synthesis of a new chalcone-trimethoxycinnamide hybrid (7) based on the combination of subunits of two promising antiproliferative compounds (CM-M345 (1) and BP-M345 (2)), previously obtained by our research group, are reported. In order to expand the structure-activity relationship (SAR) knowledge, a new series of 7-analogues was also designed and synthetized. All the compounds were evaluated for their antitumor activity against melanoma (A375-C5), breast adenocarcinoma (MCF-7), and colorectal carcinoma (HCT116) cell lines, as well as non-tumor HPAEpiC cells. Three of the newly synthesized compounds (6, 7, and 13) exhibited potent antiproliferative activity, mainly on colorectal tumor cells (GI₅₀ = 2.66-3.26 μM), showing hybrid 7 selectivity for tumor cells. We performed molecular mechanism studies to evaluate the potential interference of compounds with the p53 pathway, namely, p53-MDM2 interaction and mitosis in HCT116 cells. The antiproliferative activities of compounds were shown to be p53-independent. Compound 7 emerged as an antimitotic agent by inducing the mitotic arrest of colorectal tumor cells, and subsequently, cell death.

Therapeutic potential and limitations of curcumin as antimetastatic agent

Treatment of metastatic cancer is one of the biggest challenges in anticancer therapy. Curcumin is interesting nature polyphenolic compound with unique biological and medicinal effects, including repression of metastases. High impact studies imply that curcumin can modulate the immune system, independently target various metastatic signalling pathways, and repress migration and invasiveness of cancer cells. This review discusses the potential of curcumin as an antimetastatic agent and describes potential mechanisms of its antimetastatic activity. In addition, possible strategies (curcumin formulation, optimization of the method of administration and modification of its structure motif) to overcome its limitation such as low solubility and bioactivity are also presented. These strategies are discussed in the context of clinical trials and relevant biological studies.

Rapid screening of diarylpentanoids from Daphne bholua

Fractionation motivated by biological activity screening and NMR characteristic signals analysis led to the isolation of seventeen diarylpentanoids from the whole plant of Daphne bholua Buch.-Ham. ex D. Don, among which nine compounds were undescribed. Their structures and stereochemistry were determined by comprehensive spectroscopic data, J-based configurational analysis, and quantum chemical calculations. The inhibitory potentials of all isolates against acetylcholinesterase were evaluated in vitro and in silico.

Synthesis, Characterization, and Antiproliferative Properties of New Bio-Inspired Xanthylium Derivatives

Xanthylium derivatives are curcumin analogs showing photochromic properties. Similarly, to anthocyanins, they follow the same multistate network of chemical species that are reversibly interconverted by external stimuli. In the present work, two new asymmetric monocarbonyl analogues of curcumin, 4-(4-hydroxy-3-metoxybenzylidene)-1,2,3,4-tetrahydroxanthylium chloride (compound 3) and 4-(4-hydroxybenzylidene)-6-methoxy-1,2,3,4-tetrahydroxanthylium chloride (compound 4) were synthesized, and their photochromic and biological properties were investigated. The UV-Vis spectroscopy and the direct and reverse pH-jumps studies confirmed the halochromic properties and the existence of different molecular species. A network of chemical reactions of these species was proposed. Furthermore, the antiproliferative properties of both compounds were evaluated using P19 murine embryocarcinoma cells and compared with each other. The results demonstrate that both new xanthylium derivatives modify the progression through the cell cycle of P19 cells, which translates into a significant antiproliferative effect. The effect of the methoxy group position is discussed and several checkpoint proteins are advanced as putative targets.

Modified Curcumins as Potential Drug Candidates for Breast Cancer: An Overview

Breast cancer (BC), the most common malignancy in women, results from significant alterations in genetic and epigenetic mechanisms that alter multiple signaling pathways in growth and malignant progression, leading to limited long-term survival. Current studies with numerous drug therapies have shown that BC is a complex disease with tumor heterogeneity, rapidity, and dynamics of the tumor microenvironment that result in resistance to existing therapy. Targeting a single cell-signaling pathway is unlikely to treat or prevent BC. Curcumin (a natural yellow pigment), the principal ingredient in the spice turmeric, is well-documented for its diverse pharmacological properties including anti-cancer activity. However, its clinical application has been limited because of its low solubility, stability, and bioavailability. To overcome the limitation of curcumin, several modified curcumin conjugates and curcumin mimics were developed and studied for their anti-cancer properties. In this review, we have focused on the application of curcumin mimics and their conjugates for breast cancer.

Bioactive Diarylpentanoids: Insights into the Biological Effects beyond Antitumor Activity and Structure-Activity Relationships

Diarylpentanoids, a class of natural products and their synthetic analogs which are structurally related to chalcones, have gained increasing attention due to their wide array of biological activities, including antitumor, anti-infective, antioxidant, anti-inflammatory, antidiabetic, anti-hyperuricemic, and neuroprotective properties. Previously, we reviewed diarylpentanoids with promising antitumor activity. However, in view of the wide range of biological activities described for this class of compounds, the purpose of this review is to provide a more detailed overview of the synthetic bioactive diarylpentanoids that have been described over the last two decades, beyond simply their antitumor effects. A total of 745 compounds were found, highlighting the main synthetic methodologies used in their synthesis as well as the structure-activity relationship studies and structural features for all activities reported. Collectively, this review highlights the diarylpentanoid scaffold as a promising starting point for the development of new therapeutic agents.

New diarylpentanoids and chalcones as potential antimicrobial adjuvants

Antimicrobial resistance arises due to several adaptation mechanisms, being the overexpression of efflux pumps (EPs) one of the most worrisome. In bacteria, EPs can also play important roles in virulence, quorum-sensing (QS) and biofilm formation. To identify new potential antimicrobial adjuvants, a library of diarylpentanoids and chalcones was synthesized and tested. These compounds presented encouraging results in potentiating the activity of antimicrobials, being diarylpentanoid 13 the most promising. Compounds 9, 13, 16, 19, 22, and 23 displayed EP inhibitory effect, mainly in Staphylococcus aureus 272123. Compounds 13, 19, 22, and 23 exhibited inhibitory effect on biofilm formation in S. aureus 272,123 while 13 and 22 inhibited QS in the pair Sphingomonas paucimobilis Ezf 10-17 and Chromobacterium violaceum CV026. The overall results, demonstrated that diarylpentanoid 13 and chalcone 22 were active against all the resistance mechanisms tested, suggesting their potential as antimicrobial adjuvants.

Synthesis and Cytotoxicity of Diarylpentanoids against Sensitive CCRF-CEM and Multidrug-Resistant CEM/ADR5000 Leukemia Cells

This article described the synthesis and biological investigation of a series of symmetric diarylpentanoids, characterized by a dienone moiety and by a different pattern of substitution on the two phenyl rings. The series of compounds 1a-p were tested against drug-sensitive CCRF-CEM and multidrug-resistant CEM/ADR5000 cells to evaluate their cytotoxic profile, and all the diarypentanoids revealed to be active against both the leukemia cell lines, with the best activity shown by compound 1o that showed a submicromolar activity against both CCRF-CEM and CEM/ADR5000 cell lines (EC₅₀ =0.54 and 0.25 μM, respectively).

BP-M345, a New Diarylpentanoid with Promising Antimitotic Activity

Previously, we reported the in vitro growth inhibitory effect of diarylpentanoid BP-M345 on human cancer cells. Nevertheless, at that time, the cellular mechanism through which BP-M345 exerts its growth inhibitory effect remained to be explored. In the present work, we report its mechanism of action on cancer cells. The compound exhibits a potent tumor growth inhibitory activity with high selectivity index. Mechanistically, it induces perturbation of the spindles through microtubule instability. As a consequence, treated cells exhibit irreversible defects in chromosome congression during mitosis, which induce a prolonged spindle assembly checkpoint-dependent mitotic arrest, followed by massive apoptosis, as revealed by live cell imaging. Collectively, the results indicate that the diarylpentanoid BP-M345 exerts its antiproliferative activity by inhibiting mitosis through microtubule perturbation and causing cancer cell death, thereby highlighting its potential as antitumor agent.

Curcumin and Its New Derivatives: Correlation between Cytotoxicity against Breast Cancer Cell Lines, Degradation of PTP1B Phosphatase and ROS Generation

Breast cancer is the most common cancer of women—it affects more than 2 million women worldwide. PTP1B phosphatase can be one of the possible targets for new drugs in breast cancer therapy. In this paper, we present new curcumin derivatives featuring a 4-piperidone ring as PTP1B inhibitors and ROS inducers. We performed cytotoxicity analysis for twelve curcumin derivatives against breast cancer MCF-7 and MDA-MB-231 cell lines and the human keratinocyte HaCaT cell line. Furthermore, because curcumin is a known antioxidant, we assessed antioxidant effects in its derivatives. For the most potent cytotoxic compounds, we determined intracellular ROS and PTP1B phosphatase levels. Moreover, for curcumin and its derivatives, we performed real-time microscopy to observe the photosensitizing effect. Finally, computational analysis was performed for the curcumin derivatives with an inhibitory effect against PTP1B phosphatase to assess the potential binding mode of new inhibitors within the allosteric site of the enzyme. We observed that two tested compounds are better anticancer agents than curcumin. Moreover, we suggest that blocking the -OH group in phenolic compounds causes an increase in the cytotoxicity effect, even at a low concentration. Furthermore, due to this modification, a higher level of ROS is induced, which correlates with a lower level of PTP1B.

Diarylpentanoid (1,5-bis(4-hydroxy-3-methoxyphenyl)-1,4-pentadiene-3-one) (MS13) Exhibits Anti-proliferative, Apoptosis Induction and Anti-migration Properties on Androgen-independent Human Prostate Cancer by Targeting Cell Cycle-Apoptosis and PI3K Signalling Pathways

Diarylpentanoids exhibit a high degree of anti-cancer activity and stability in vitro over curcumin in prostate cancer cells. Hence, this study aims to investigate the effects of a diarylpentanoid, 1,5-bis(4-hydroxy-3-methoxyphenyl)-1,4-pentadiene-3-one (MS13) on cytotoxicity, anti-proliferative, apoptosis-inducing, anti-migration properties, and the underlying molecular mechanisms on treated androgen-independent prostate cancer cells, DU 145 and PC-3. A cell viability assay has shown greater cytotoxicity effects of MS13-treated DU 145 cells (EC₅₀ 7.57 ± 0.2 µM) and PC-3 cells (EC₅₀ 7.80 ± 0.7 µM) compared to curcumin (EC₅₀: DU 145; 34.25 ± 2.7 µM and PC-3; 27.77 ± 6.4 µM). In addition, MS13 exhibited significant anti-proliferative activity against AIPC cells compared to curcumin in a dose- and time-dependent manner. Morphological observation, increased caspase-3 activity, and reduced Bcl-2 protein levels in these cells indicated that MS13 induces apoptosis in a time- and dose-dependent. Moreover, MS13 effectively inhibited the migration of DU 145 and PC-3 cells. Our results suggest that cell cycle-apoptosis and PI3K pathways were the topmost significant pathways impacted by MS13 activity. Our findings suggest that MS13 may demonstrate the anti-cancer activity by modulating DEGs associated with the cell cycle-apoptosis and PI3K pathways, thus inhibiting cell proliferation and cell migration as well as inducing apoptosis in AIPC cells.

A Diarylpentanoid with Potential Activation of the p53 Pathway: Combination of in silico Screening Studies, Synthesis, and Biological Activity Evaluation

In silico studies of a library of diarylpentanoids led us to the identification of potential new MDM2/X ligands. The diarylpentanoids with the best docking scores obeying the druglikeness and ADMET prediction properties were subsequently synthesized and evaluated for their antiproliferative activity on colon cancer HCT116 and fibroblasts HFF-1 cells. The effect on p53-MDM2/X interactions was evaluated through yeast-based assays for compounds showing potent antiproliferative activity in HCT116 cells and low toxicity in normal cells, resulting in the identification of a potential dual inhibitor. Moreover, its antiproliferative effect was significantly reduced in the absence of p53 and in MDA-MB-231 cells expressing a mutant p53 form. The antiproliferative effect of this compound was associated with induction of cell cycle arrest, apoptosis, PARP cleavage and increased p53 and its transcriptional targets, p21 and PUMA, in HCT116 cells. Docking poses and residues involved in the inhibition of p53-MDM2/X interactions were predicted by docking studies.

A New Pentafluorothio-Substituted Curcuminoid with Superior Antitumor Activity

A new and readily available pentafluorothiophenyl-substituted N-methyl-piperidone curcuminoid 1a was prepared and investigated for its anti-proliferative, pro-apoptotic and cancer stem cell-differentiating activities against a panel of human tumor cell lines derived from various tumor entities. The compound 1a was highly anti-proliferative and reached IC₅₀ values in the nanomolar concentration range. 1a was superior to the known anti-tumorally active curcuminoid EF24 (2) and its known N-ethyl-piperidone analog 1b in all tested tumor cell lines. Furthermore, 1a induced a noticeable increase of intracellular reactive oxygen species in HT-29 colon adenocarcinoma cells, which possibly leads to a distinct increase in sub-G1 cells, as assessed by cell cycle analysis. A considerable activation of the executioner-caspases 3 and 7 as well as nuclei fragmentation, cell rounding, and membrane protrusions suggest the triggering of an apoptotic mechanism. Yet another effect was the re-organization of the actin cytoskeleton shown by the formation of stress fibers and actin aggregation. 1a also caused cell death in the adherently cultured glioblastoma cell lines U251 and Mz54. We furthermore observed that 1a strongly suppressed the stem cell properties of glioma stem-like cell lines including one primary line, highlighting the potential therapeutic relevance of this new compound.

Turmeric and Curcumin: From Traditional to Modern Medicine

The rhizome of turmeric (Curcuma longa L.) has been used as an herbal medicine, coloring agent, spice, and food additive for thousands of years in different parts of the world particularly in Asian countries. It has been used for a range of diseases in many traditional medical schools, including Islamic traditional medicine, Chinese traditional medicine, and Ayurveda. It has been used mainly for digestive problems, as a cardio-, hepato-, and neuroprotective agent as well as in many inflammatory conditions such as arthritis and for enhancing immune system. Curcumin, a diarylheptanoid derivative found in turmeric, has anti-inflammatory, antioxidant, and anticancer properties; controls obesity and metabolic problems; and improves memory and mood disorders. Therapeutically, curcumin exhibits promising potential in preclinical and clinical studies and is currently in human trials for a variety of conditions, including metabolic syndrome, nonalcoholic fatty liver disease, rheumatoid arthritis, migraine, premenstrual syndrome, ulcerative colitis, knee osteoarthritis, polycystic ovarian syndrome, atherosclerosis, liver cirrhosis, amyotrophic lateral sclerosis, depression, psoriasis, and Alzheimer's disease. Among all beneficial activities reported for curcumin, the research toward the obesity and metabolic-preventing/suppressing aspects of curcumin is growing. These findings emphasize that most of the traditional applications of turmeric is due to the presence of its key constituent, curcumin. According to the traditional background of turmeric use and clinical values of curcumin, further preclinical studies for unstudied properties and clinical studies with larger sample sizes for confirmed activities are expected.