Design, Synthesis, Anticancer Evaluation and Docking Studies of Novel Heterocyclic Derivatives Obtained via Reactions Involving Curcumin

Synthesis of hydrazone-based polyhydroquinoline derivatives - antibacterial activities, α-glucosidase inhibitory capability, and DFT study

In recent years, polyhydroquinolines have gained much attention due to their widespread applications in medicine, agriculture, industry, etc. Here, we synthesized a series of novel hydrazone-based polyhydroquinoline derivatives via multi-step reactions. These molecules were characterized by modern spectroscopic techniques (1H-NMR, 13C NMR, and LC-HRMS) and their antibacterial and in vitro α-glucosidase inhibitory activities were assessed. Compound 8 was found to be the most active inhibitor against Listeria monocytogenes NCTC 5348, Bacillus subtilis IM 622, Brevibacillus brevis, and Bacillus subtilis ATCC 6337 with a zone of inhibition of 15.3 ± 0.01, 13.2 ± 0.2, 13.1 ± 0.1, and 12.6 ± 0.3 mm, respectively. Likewise, compound 8 also exhibited the most potent inhibitory potential for α-glucosidase (IC50 = 5.31 ± 0.25 μM) in vitro, followed by compounds 10 (IC50 = 6.70 ± 0.38 μM), and 12 (IC50 = 6.51 ± 0.37 μM). Furthermore, molecular docking and DFT analysis of these compounds showed good agreement with experimental work and the nonlinear optical properties calculated here indicate that these compounds are good candidates for nonlinear optics.

The Michael donor-acceptor reactivity of curcumins in the synthesis of diverse multi-functional scaffolds

Curcumin is a key constituent of turmeric with a variety of biological activities. From a chemical point of view, curcumin contains different functional groups that can undergo multiple transformations such as Michael addition, cycloaddition, click reaction, polymerisation, etc. Among these, Michael-type reactions under benign conditions constitute a captivating domain of curcumin's reactivity. To the best of our knowledge, no review focusing on the Michael donor-acceptor reactivity of curcumins has been published to date. Herein, we have compiled the chemistry of curcumins with respect to their chemical synthesis, biosynthesis, and involvement in chemical transformations, especially in Michael additions with advances in mechanistic aspects and understanding.

Advances in β-Diketocyclisation of Curcumin Derivatives and their Antitumor Activity

Curcumin, derived from the popular spice turmeric, is a pharmacologically active polyphenol. Curcumin's therapeutic activity has been extensively studied in recent decades, with reports implicating curcumin in many biological activities, particularly, its significant anticancer activity. However, its potential as an oral administration product is hampered by poor bioavailability, which is associated with a variety of factors, including low water solubility, poor intestinal permeability, instability, and degradation at alkaline pH. To improve its bioavailability, modifying β-diketone curcumin with heterocycles, such as pyrazole, isoxazole and triazole is a powerful strategy. Derivatives are synthesized while maintaining the basic skeleton of curcumin. The β-diketone cyclized curcumin derivatives are regulators of multiple molecular targets, which play vital roles in a variety of cellular pathways. In some literatures, structurally modified curcumin derivatives have been compared with curcumin, and the former has enhanced biological activity, improved water solubility and stability. Therefore, the scope of this review is to report the most recently synthesized heterocyclic derivatives and to classify them according to their chemical structures. Several of the most important and effective compounds are reviewed by introducing different active groups into the β-diketone position to achieve better therapeutic efficacy and bioavailability.

Ultrasonic-Assisted Synthesis of Heterocyclic Curcumin Analogs as Antidiabetic, Antibacterial, and Antioxidant Agents Combined with in vitro and in silico Studies

Background

Heterocyclic analogs of curcumin have a wide range of therapeutic potential and the ability to control the activity of a variety of metabolic enzymes.

Methods

1H-NMR and 13C-NMR spectroscopic techniques were used to determine the structures of synthesized compounds. The agar disc diffusion method and α-amylase inhibition assay were used to examine the antibacterial and anti-diabetic potential of the compounds against α-amylase enzyme inhibitory activity, respectively. DPPH-free radical scavenging and lipid peroxidation inhibition assays were used to assess the in vitro antioxidant potential.

Results and Discussion

In this work, nine heterocyclic analogs derived from curcumin precursors under ultrasonic irradiation were synthesized in excellent yields (81.4-93.7%) with improved reaction time. Results of antibacterial activities revealed that compounds 8, and 11 displayed mean inhibition zone of 13.00±0.57, and 19.66±00 mm, respectively, compared to amoxicillin (12.87±1.41 mm) at 500 μg/mL against E. coli, while compounds 8, 11 and 16 displayed mean inhibition zone of 17.67±0.57, 14.33±0.57 and 23.33±00 mm, respectively, compared to amoxicillin (13.75±1.83 mm) at 500 μg/mL against P. aeruginosa. Compound 11 displayed a mean inhibition zone of 11.33±0.57 mm compared to amoxicillin (10.75±1.83 mm) at 500 μg/mL against S. aureus. Compound 11 displayed higher binding affinities of -7.5 and -8.3 Kcal/mol with penicillin-binding proteins (PBPs) and β-lactamases producing bacterial strains, compared to amoxicillin (-7.2 and -7.9 Kcal/mol, respectively), these results are in good agreement with the in vitro antibacterial activities. In vitro antidiabetic potential on α-amylase enzyme revealed that compounds 11 (IC50=7.59 µg/mL) and 16 (IC50=4.08 µg/mL) have higher inhibitory activities than acarbose (IC50=8.0 µg/mL). Compound 8 showed promising antioxidant inhibition efficacy of DPPH (IC50 = 2.44 g/mL) compared to ascorbic acid (IC50=1.24 g/mL), while compound 16 revealed 89.9±20.42% inhibition of peroxide generation showing its potential in reducing the development of lipid peroxides. In silico molecular docking analysis, results are in good agreement with in vitro biological activity. In silico ADMET profiles suggested the adequate oral drug-likeness potential of the compounds without adverse effects.

Conclusion

According to our findings, both biological activities and in silico computational studies results demonstrated that compounds 8, 11, and 16 are promising α-amylase inhibitors and antibacterial agents against E. coli, P. aeruginosa, and S. aureus, whereas compound 8 was found to be a promising antioxidant agent.

Antibacterial Potential of Novel Acetamide Derivatives of 2-Mercaptobenzothiazole: Synthesis and Docking Studies

2-Mercaptobenzothiazole and its derivatives are widely known for their diverse biological activities, particularly antimicrobial and anticancer potential. In the present study, a series of new hybrid compounds consisting of 2-mercaptobenzothiazole and different aryl amines 2(a-j) were synthesized and characterized by Fourier transform infrared (FTIR), ¹H NMR, and ¹³C NMR spectral data. The synthesized compounds were screened for in vitro antibacterial activities through agar well diffusion assay. Among the series, 2b, 2c, and 2i exhibited significant antibacterial activity comparable to the standard drug levofloxacin. Based on their antibacterial potential, these compounds were further tested for their antibiofilm activity. All of the three compounds showed promising antibiofilm potential, even better than the standard drug cefadroxil at 100 μg/100 μL concentration. Molecular docking studies were performed to explore the antibacterial mechanism of these compounds. Strikingly, the molecule 2i shared the same hydrophobic pockets as those of levofloxacin in case of bacterial kinases and DNA gyrases. In addition, 2i exhibited satisfactory antibiofilm activity in comparison to the standard. Our study therefore suggested that the synthetic compound 2i possesses remarkable antibacterial activity and may serve as a lead molecule for the discovery of potent antibacterial agents.

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.

Mechanistic Insights and Docking Studies of Phytomolecules as Potential Candidates in the Management of Cancer

BACKGROUND

Cancer is a leading risk of death globally. According to the World Health Organization, it is presently the second most important disease that causes death in both developing and developed countries. Remarkable progress has been made in the war against cancer with the development of numerous novel chemotherapy agents. However, it remains an immense challenge to discover new efficient therapeutic potential candidates to combat cancer.

OBJECTIVES

The majority of the currently used anticancer drugs are of natural origins, such as curcumin, colchicine, vinca alkaloid, paclitaxel, bergenin, taxols, and combretastatin. Concerning this, this review article presents the structure of the most potent molecules along with IC50 values, structure-activity relationships, mechanistic studies, docking studies, in silico studies of phytomolecules, and important key findings on human cancer cell lines.

METHODS

A viewpoint of drug design and development of antiproliferative agents from natural phytomolecules has been established by searching peer-reviewed literature from Google Scholar, PubMed, Scopus, Springer, Science Direct, and Web of Science over the past few years.

RESULTS

Our analysis revealed that this article would assist chemical biologists and medicinal chemists in industry and academia in gaining insights into the anticancer potential of phytomolecules.

CONCLUSION

In vitro and in silico studies present phytomolecules, such as curcumin, colchicine, vinca alkaloids, colchicine, bergenin, combretastatin, and taxol encompassing anticancer agents, offerings abundant sanguinity and capacity in the arena of drug discovery to inspire the investigators towards the continual investigations on these phytomolecules. It is extremely expected that efforts in this track will strengthen and grant some budding cancer therapeutics candidates in the near future.

Curcumin as a Potential Therapeutic Agent in Certain Cancer Types

Cancer is a devastating disease condition and is the second most common etiology of death globally. After decades of research in the field of hematological malignancies and cellular therapeutics, we are still looking for therapeutic agents with the most efficacies and least toxicities. Curcumin is one of the cancer therapeutic agents that is derived from the Curcuma longa (turmeric) plant, and still in vitro and in vivo research is going on to find its beneficial effects on various cancers. Due to its potency to affect multiple targets of different cellular pathways, it is considered a promising agent to tackle various cancers alone or in combination with the existing chemotherapies. This review covers basic properties, mechanism of action, potential targets (molecules and cell-signaling pathways) of curcumin, as well as its effect on various solid and hematological malignancies. 

Incorporation of green emission polymer dots into pyropheophorbide-α enhance the PDT effect and biocompatibility

BACKGROUND

A green emission up-conversion carbon-based polymer dots (CPDs) owned excellent photophysical properties and good solubility. Most photosensitizers (PS) are hydrophobic which limits their application in biomedicine. Herein we synthesized and integrated green emitting CPDs into pyropheophorbide-α (PPa) to improve the overall properties of the PS.

MATERIAL AND METHODS

The nano-agent was incorporated through amide condensation and electrostatic interaction. The structure, size and morphology of the prepared conjugates were determined by FTIR, TEM, DLS, TGA, ¹HNMR, Uv-vis, and fluorescence spectrophotometry. The dark and light toxicity, as well as cellular uptake, was also monitored on the human esophageal cancer cell line (Eca-109).

RESULTS

Our results illustrate that the conjugation improved the PDT efficacy by increasing the ROS generation. The nano-hybrids showed pH sensitivity as well as good hemocompatibility as the hemolysis ratio was decreased when treated with nano-conjugates. PPa-CPD1 and PPa-CPD2 had the pH response and stronger ability to absorb light and produce fluorescence in an acidic environment (pH 4.0 and pH 5.0) The synthesized nano-hybrids doesnot affect the clotting time. An increase in the absorbance wavelengths was observed. The results of MTT assay showed that dark toxicity was reduced after conjugation.

CONCLUSION

This CPDs-based drug enhanced tumor-inhibition efficiency as well as low dark toxicity in vitro, showing significant application potential for PDT-based treatment.

Synthesis and bio-properties of 4-piperidone containing compounds as curcumin mimics

3,5-Diyliden-4-piperidone scaffold are considered as curcumin mimic exhibiting diverse bio-properties.

The improvement of biocompatibility by incorporating porphyrins into carbon dots with photodynamic effects and pH sensitivities

Photodynamic therapy (PDT) is a promising new treatment for cancer; however, the hydrophobic interactions and poor solubility in water of photosensitizers limit the use in clinic. Nanoparticles especially carbon dots have attracted the attention of the world^'s scientists because of their unique properties such as good solubility and biocompatibility. In this paper, we integrated carbon dots with different porphyrins to improve the properties of porphyrins and evaluated their efficacy as PDT drugs. The spectroscopic characteristics of porphyrins nano-conjugates were studied. Singlet oxygen generation rate and the light- and dark-induced toxicity of the conjugates were studied. Our results showed that the covalent interaction between CDs and porphyrins has improved the biocompatibility. The synthesized conjugates also inherit the pH sensitivity of the carbon dots, while the conjugation also decreases the hemolysis ratio making them a promising candidate for PDT. The incorporation of carbon dots into porphyrins improved their biocompatibility by reducing toxicity.

The Photodynamic Anti-Tumor Effects of New PPa-CDs Conjugate with pH Sensitivity and Improved Biocompatibility

BACKGROUND

Photodynamic therapy has been increasingly used to cope with the alarming problem of cancer. Porphyrins and its derivatives are widely used as potent photosensitizers (PS) for PDT. However, hydrophobicity of porphyrins poses a challenge for their use in clinics, while most of the carbon dots (CDs) are known for good biocompatibility, solubility, and pH sensitivity.

OBJECTIVE

To improve the properties/biocompatibility of the pyropheophorbide-α for PDT.

METHODS

PPa-CD conjugate was synthesized through covalent interaction using amide condensation. The structure of synthesized conjugate was confirmed by TEM, 1HNMR, and FTIR. The absorption and emission spectra were studied. In vitro, cytotoxicity of the conjugate was examined in the Human esophageal cancer cell line (Eca-109).

RESULTS

The results showed that the fluorescence of the drug was increased from its precursor. CD based conjugate could generate ROS as well as enhanced the biocompatibility by decreasing the cytotoxicity. The conjugated drug also showed pH sensitivity in different solutions.

CONCLUSION

The dark toxicity, as well as hemocompatibility, were improved.

Synthesis and in vitro PDT evaluation of red emission polymer dots (R-CPDs) and pyropheophorbide-α conjugates

Carbon based polymer dots have piqued attention of researchers because of excellent biocompatibility, and good solubility. Most of the p-dots are able to generate ROS which is effective for photodynamic therapy for the treatment of cancer while some photosensitizers such as porphyrins possess some drawbacks such as hydrophobicity, and dark toxicity. Therefore in this study we conjugated red emission carbon based polymer with pyropheophorbide-α through amide condensation and π-π stacking. One pot synthesis of the conjugate was successfully achieved. Their photophysiological properties were studied and structures were characterized by FT-IR, TEM and ¹HNMR. pH- sensitivity of the conjugates was confirmed using fluorescence and UV-vis spectroscopy. Photo toxicity and dark toxicity of the prepared conjugates were evaluated in human esophageal cancer cell line (Eca-109). Hemocompatibility of the synthesized conjugates was evaluated and proved that the conjugates are safe to use for the treatment of tumor. Our results showed the PS doped p-dots had less dark toxicity and increased light toxicity as well as ROS generation was high as compared to precursor drug. Therefore, incorporation of p-dots to porphyrin improved biocompatibility and enhanced the photodynamic effect.

Curcuma Longa, the "Golden Spice" to Counteract Neuroinflammaging and Cognitive Decline-What Have We Learned and What Needs to Be Done

Due to the global increase in lifespan, the proportion of people showing cognitive impairment is expected to grow exponentially. As target-specific drugs capable of tackling dementia are lagging behind, the focus of preclinical and clinical research has recently shifted towards natural products. Curcumin, one of the best investigated botanical constituents in the biomedical literature, has been receiving increased interest due to its unique molecular structure, which targets inflammatory and antioxidant pathways. These pathways have been shown to be critical for neurodegenerative disorders such as Alzheimer’s disease and more in general for cognitive decline. Despite the substantial preclinical literature on the potential biomedical effects of curcumin, its relatively low bioavailability, poor water solubility and rapid metabolism/excretion have hampered clinical trials, resulting in mixed and inconclusive findings. In this review, we highlight current knowledge on the potential effects of this natural compound on cognition. Furthermore, we focus on new strategies to overcome current limitations in its use and improve its efficacy, with attention also on gender-driven differences.

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.

The potency of heterocyclic curcumin analogues: An evidence-based review

Curcumin, a potent phytochemical, has been a significant lead compound and has been extensively investigated for its multiple bioactivities. Owing to its natural origin, non-toxic, safe, and pleiotropic behavior, it has been extensively explored. However, several limitations such as its poor stability, bioavailability, and fast metabolism prove to be a constraint to achieve its full therapeutic potential. Many approaches have been adopted to improve its profile, amongst which, structural modifications have indicated promising results. Its symmetric structure and simple chemistry have prompted organic and medicinal chemists to manipulate its arrangement and study its implications on the corresponding activity. One such recurring and favorable modification is at the diketo moiety with the aim to achieve isoxazole and pyrazole analogues of curcumin. A modification at this site is not only simple to achieve, but also has indicated a superior activity consistently. This review is a comprehensive and wide-ranged report of the different methods adopted to achieve several cyclized curcumin analogues along with the improvement in the efficacy of the corresponding activities observed.

Synthesis and evaluation of novel fluorinated hematoporphyrin ether derivatives for photodynamic therapy

A photosensitizer with high phototoxicity, suitable amphipathy and low dark toxicity could play a pivotal role in photodynamic therapy (PDT). In this study, a facile and versatile approach was adopted to synthesize a series of novel fluorinated hematoporphyrin ether derivatives (I1-I5 and II1-II4), and the photodynamic activities of these compounds were studied. Compared to hematoporphyrin monomethyl ether (HMME), all PSs showed preferable photodynamic activity against A549 lung tumor cells. The longest visible absorption wavelength of these compounds was approximately 622 nm. Among them, II3 revealed the highest singlet oxygen yield (0.0957 min-1), the strongest phototoxicity (IC50 = 1.24 μM), the lowest dark toxicity in vitro, and exhibited excellent anti-tumor effects in vivo. So compound II3 could act as new drug candidate for photodynamic therapy.

Therapeutic role of curcumin and its novel formulations in gynecological cancers

Gynecological cancers are among the leading causes of cancer-associated mortality worldwide. While the number of cases are rising, current therapeutic approaches are not efficient enough. There are considerable side-effects as well as treatment resistant types. In addition, which all make the treatment complicated for afflicted cases. Therefore, in order to improve efficacy of the treatment process and patients’ quality of life, searching for novel adjuvant treatments is highly warranted. Curcumin, a promising natural compound, is endowed with numerous therapeutic potentials including significant anticancer effects. Recently, various investigations have demonstrated the anticancer effects of curcumin and its novel analogues on gynecological cancers. Moreover, novel formulations of curcumin have resulted in further propitious effects. This review discusses these studies and highlights the possible underlying mechanisms of the observed effects.

Molecular Docking Simulation Studies of Curcumin and Its Derivatives as Cyclin-Dependent Kinase 2 Inhibitors

Objectives

Cyclin-dependent kinase 2 (CDK2) is a protein that plays a role in regulating the cell cycle and its overexpression contributes to uncontrolled cell proliferation. Inhibition of CDK2 is known to be a mechanism of action of various anti-cancer drugs. Curcumin is an active compound of Curcuma longa and it has been reported to inhibit the activity of cyclin D, cyclin E, CDK2, CDK4, and CDK6. This study aimed to design more active curcumin derivatives as anticancer drugs by targeting CDK2 through a molecular modeling approach.

Materials and Methods

The molecular modeling approach consists of receptor and ligand preparation, method validation, pharmacophore modeling, and docking simulation.

Results

The results of the molecular docking simulation show that the free bonding energy (ΔG) of curcumin and kurkumod 23 and 24 (the best modification of curcumin) are -7.80, -9.15, and -9.36 kcal/mol, respectively. The hydrogen interaction between kurkumod 23 and 24 with CDK occurred on Lys33 residue, which is considered a potential interaction site for CDK2 inhibitor compounds. Pharmacophore modeling showed that kurkumod 23 and 24 have pharmacophore-fit values of 45.20% and 47.26%, respectively.

Conclusion

The results of this study indicate that kurkumod 23 and 24 are the best and most potent modifications of curcumin as CDK2 antagonist, based on the interactions that occur between these two derivatives with amino acid residues from the CDK2 receptor.

One-Pot Synthesis of Novel Furochromone and Oxazocine Derivatives as Promising Antitumor Agents with Their Molecular Docking Studies

One-pot efficient synthesis of novel chromone derivatives 4a–h and that of 5a–h were described in a simple method via four-component reaction between furochromone carbaldehyde, amine, isocyanate derivatives, and benzoic acid derivatives or nicotinic acid, respectively. Also, oxazocine derivatives 7a, b were prepared via reaction of visnagine carbaldehyde, ethyl acetoacetate and isocyanate derivatives 2a, b. The obtained derivatives of novel furochromone and oxazocine derivatives were evaluated as promising antitumor agents against panel of two human cell lines, hepatocellular carcinoma (HEPG2) and breast carcinoma (MCF7). The antitumor results suggested that furochromone derivatives 5a–h have activity against MCF7 in comparison with doxorubicin as the standard drug. Furthermore, the molecular docking studies of these novel derivatives of furochromone and oxazocine showed good agreement with the biological results when their binding pattern and affinity towards the active site of EGFR was investigate.

One-pot synthesis of thiazolo[3,2-a]pyrimidine derivatives, their cytotoxic evaluation and molecular docking studies

An economical, simple and efficient one-pot method has been developed for the synthesis of thiazolo[3,2-a]pyrimidine hydrobromide derivatives. 2,4-diaryl-6,7,8,9-tetrahydro-4H-benzo[4,5]thiazolo[3,2-a]pyrimidine hydrobromides were synthesized by the α-bromination of cyclohexanone with N-Bromosuccinamide (NBS) and followed by cyclization with 3,4-dihydropyrimidine-2(1H)-thiones, respectively, in the presence of p-toluenesulfonic acid (PTSA) in acetonitrile. However when cyclohexanone was replaced by acetyl acetone and alpha-tetralone gave the corresponding 1-(3-methyl-5,7-diaryl-5H-thiazolo[3,2-a]pyrimidin-2-yl)ethan-1-one hydrobromide and 9,11-diaryl-6,11-dihydro-5H-naphtho[1',2':4,5]thiazolo[3,2-a]pyrimidine hydrobromide derivatives, respectively. The significant features of this method are novel, simple, inexpensive experimental procedure, short reaction time, and good yield. The some of the synthesized compounds were evaluated for cytotoxic activity against human lung adenocarcinoma cell line (A549), human breast carcinoma cell line (MCF-7), human cervical cancer cell line (HeLa) and human neuronal carcinoma cell lines (SKNSH). Tested compounds 5(b-e) showed the excellent anticancer activity against various cell lines. Particularly compound 5c with IC₅₀ value of 2.2 ± 0.6 μM against A549 and compound 5e with IC₅₀ value of 5.6 ± 0.4 μM against HeLa showed best cytotoxic effects. Furthermore, Molecular docking study was performed for some of the synthesized compounds 5(b-e) against topoisomerase-II by using Auto dock method. Docking results of the compounds 5c, 5d, and 5e exhibited higher cytotoxic activity than the standard doxorubicin.

Synthesis and biological evaluation of dehydroabietic acid-pyrimidine hybrids as antitumor agents

A series of novel dehydroabietic acid derivatives containing pyrimidine moieties were designed and synthesized. Some of them displayed more potent inhibitory activities compared with 5-FU.

Synthesis of pyrano[2,3-f]chromen-2-ones vs. pyrano[3,2-g]chromen-2-ones through site controlled gold-catalyzed annulations

Regioselective access to 10-substituted-2H,8H-pyrano[2,3-f]chromen-2-ones through the gold-catalyzed intramolecular hydroarylation of readily available 7-(prop-2-yn-1-yloxy)-2H-chromen-2-one derivatives at their C-8 congested position was investigated by tuning the electronic and steric properties of the ligand on the gold complex. On the other hand, the combination of the JohnPhosAu(MeCN)SbF6 catalyzed intramolecular hydroarylation of 8-iodo-7-(prop-2-yn-1-yloxy)-2H-chromen-2-one derivatives followed by selective palladium/formate C-I reduction allows for the exclusive formation of 2H,8H-pyrano[3,2-g]chromen-2-one regioisomers. The development of these two protocols provides versatile synthetic tools required for exploring the biological activities of these new pyranocoumarin derivatives.

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.

Design, synthesis, molecular modelling, and biological evaluation of novel substituted pyrimidine derivatives as potential anticancer agents for hepatocellular carcinoma

New anticancer agents are highly needed to overcome cancer cell resistance. A novel series of pyrimidine pyrazoline-anthracene derivatives (PPADs) (4a-t) were designed and synthesised. The anti-liver cancer activity of all compounds was screened in vitro against two hepatocellular carcinoma (HCC) cell lines (HepG2 and Huh-7) as well as normal fibroblast cells by resazurin assay. The designed compounds 4a-t showed a broad-spectrum anticancer activity against the two cell lines and their activity was more prominent on cancer compared to normal cells. Compound 4e showed high potency against HepG2 and Huh-7 cell lines ((IC₅₀=5.34 and 6.13 μg/mL, respectively) comparable to that of doxorubicin (DOX) activities. A structure activity relationship (SAR) has been investigated and compounds 4e, 4i, 4m, and 4q were the most promising anticancer agents against tested cell lines. These compounds induced apoptosis in HepG2 and Huh-7 cells through significant activation of caspase 3/7 at all tested concentrations. In conclusion, 4e could be a potent anticancer drug.

Developments in the anticancer activity of structurally modified curcumin: An up-to-date review

Curcumin is a pharmacologically active polyphenol derived from the popular spice element-Turmeric. The therapeutic activity of curcumin has been extensively investigated over the last few decades and reports suggest the role of curcumin in a large number of biological activities, particularly its prominent anticancer activity. Curcumin, being a pleiotropic molecule, is a regulator of multiple molecular targets which play crucial roles in various cell signaling pathways. It is known to suppress transformation, inhibit proliferation as well as induce apoptosis. However, despite all these benefits, the efficacy of curcumin remains limited due to its poor bioavailability, poor absorption within the systemic circulation and rapid elimination from the body. To overcome these limiting factors, researchers all around the world are working towards designing a synthetic and superior curcuminoid by making suitable structural modifications to the parent skeleton. These curcuminoids, mainly analogues and derivatives, will not only improve the physicochemical properties but also enhance the efficacy simultaneously. The present review will provide a comprehensive account of the analogues and derivatives of curcumin that have been reported since 2014 which have indicated a better anticancer activity than curcumin.