Synthesis and biological evaluation of novel bavachinin analogs as anticancer agents

Synthesis and antitumor activity of dolutegravir derivatives bearing 1,2,3-triazole moieties

Modification of marketed drugs is an important way to develop drugs because its safety and clinical applicability. Oxygen-nitrogen heterocycles are a class of important active substances discovered in the process of new drug development. Dolutegravir, an HIV drug with a nitrogen-oxygen heterocycle structure, has the potential ability to inhibit cell survival. In order to find and explore novel anti-tumor drugs, new dolutegravir derivatives bearing different 1,2,3-triazole moieties were prepared via click reactions. In vitro biological experiments performed in several lung cancer cell lines suggested that these novel compounds displayed potent anti-tumor ability. Especially, the compound 9e with a substituent of 2-methyl-3-nitrophenyl and the compound 9p with a substituent of 3-trifluoromethylphenyl were effective against PC-9 cell line with IC50 values of 3.83 and 3.17 µM, respectively. Moreover, compounds 9e and 9p were effective against H460 and A549 cells. Further studies suggested that compounds 9e and 9p could induce cancer cell apoptosis in PC-9 and H460, inhibit cancer cell proliferation, change the cell cycle, and increase the level of reactive oxygen species (ROS) which further induce tumor cell apoptosis. In addition, compounds 9e and 9p increased LC3 protein expression which was the key regulator in autophagy signaling pathway in PC-9 cells. Compound 9e also showed low toxicity against normal cells, and could be regarded as an interesting lead compound for further structure optimization.

Apoptotic Potential and Antitumor Efficacy of Trilliumoside A: A New Steroidal Saponin Isolated from Rhizomes of Trillium govanianum

Natural product-derived molecules exhibit potential as anticancer agents. Trilliumoside A, a new steroidal saponin, was obtained from rhizomes of Trillium govanianum, and its anticancer activity was investigated in the presented study. Trilliumoside A was investigated in a panel of cell lines, and it exhibited promising cytotoxic activity on the A549 cells (human lung cancer cells) with an IC50 of 1.83 μM. The mechanism of cell death induced by Trilliumoside A in A549 cells and its anticancer potential in murine tumor models (EAC and EAT) were presented in the current research. Trilliumoside A was found to induce apoptosis in A549 cells by increasing the expression of various apoptotic proteins, such as Bax, Puma, cytochrome C, cleaved PARP, and cleaved caspase 3. Additionally, Trilliumoside A regulates the expression of p53, CDK2, and Cyclin A by decreasing the mitochondrial membrane potential, elevating reactive oxygen species, and stopping the growth of A549 cells in the synthesis phase (S) of the cell cycle. Trilliumoside A showed a considerable reduction in the tumor volume, the amount of ascitic fluid, and the total cell number without affecting the body weight of animals. Our results demonstrate that Trilliumoside A inhibits the proliferation of human lung cancer cells by inducing DNA damage, arresting the cell cycle, and activating the mitochondrial signaling pathway. The study demonstrated the potential of Trilliumoside A as a potential anticancer agent.

Site-Selective Synthesis of C-17 Ester Derivatives of Natural Andrographolide for Evaluation as a Potential Anticancer Agent

A library of 57 compounds of natural andrographolide was designed, synthesized, and screened for in vitro studies against four human cancer cell lines: A594, PC-3, MCF-7, and HCT-116. Most of the synthesized compounds displayed better cytotoxic profile against all tested cells compared to the parent andrographolide (1). The tested semisynthetic derivatives of andrographolide were found to be more sensitive toward lung carcinoma (A594) and prostate carcinoma (PC-3) cell lines. Among the synthesized compounds, the C-17 p-methoxy phenyl ester analog 8s inhibited cell proliferation effectively in A549 (IC₅₀: 6.6 μM) and PC-3 (IC₅₀: 5.9 μM) cell variants, and compound 9s exhibited the most potent activity against the A594 cell line, with an IC₅₀ value of 3.5 μM. Further anticancer mechanistic investigation demonstrated that compound 9s displayed nuclear morphological changes and increased reactive oxygen species (ROS) with disturbed mitochondrial membrane potential (MMP) that can lead to apoptosis. To know the exact structure confirmation of intermediate compounds 4 and 5, single X-ray crystallography was performed, which supported the complete reaction design of this work.

A bavachinin analog, D36, induces cell death by targeting both autophagy and apoptosis pathway in acute myeloid leukemia cells

PURPOSE

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy with high mortality, and it is urgent to find new and optimized treatment strategies for AML. In this study, bavachinin, isolated from Psoralea corylifolia L. exhibiting extensive anti-tumor activity in many solid tumors and a series of its synthesized analogs, were screened for their anti-cancer activity on AML cell lines.

METHODS

The cell viability of AML cells was measured using CCK-8 assays. Cell apoptosis and cell cycle were detected by flow cytometry. The expression of apoptosis-related protein and autophagy-related protein/gene was detected by western blot, immunofluorescence or RT-PCR. Subcutaneous mice tumor model was used to evaluate the anti-cancer activity of D36 in vivo.

RESULTS

D36 robustly induced AML cells death in a dose-dependent manner with the IC₅₀ value of 1.0 μM for HL-60 cells and 0.81 μM for MV4-11 cells at 24 h. D36 activated autophagy by inducing the accumulation of LC3B and promoting the autophagy flux. In addition, D36 triggered the extrinsic apoptosis by upregulating the protein level of FAS, cleaved-caspase 8, cleaved-caspase 3 and cleaved-PARP. D36 also blocked the cell cycle at S phase or G₂/M phase in AML cells. In addition, we find that activation of caspase cascade induced apoptosis and meanwhile activated autophagy, autophagy activation in turns contributes to apoptosis. Furthermore, D36 suppressed the tumor growth in HL-60 AML-bearing mice without obvious side effects.

CONCLUSION

This study suggests that D36 is a promising small-molecule for the treatment of acute myeloid leukemia.

Synthesis and biological evaluation of isatin oxime ether-tethered aryl 1H-1,2,3-triazoles as inhibitors of Mycobacterium tuberculosis

A series of isatin oxime ether-tethered aryl 1H-1,2,3-triazole hybrids were synthesized and screened for their in vitro antitubercular activity against the M. tuberculosis H37Rv strain.

Recent Advances in Bioactive Flavonoid Hybrids Linked by 1,2,3-Triazole Ring Obtained by Click Chemistry

As a result of the biological activities of natural flavonoids, several synthetic strategies aiming to obtain analogues with improved potency and/or pharmacokinetic profile have been developed. Since the triazole ring has been associated with several biological activities and metabolic stability, hybridization with a 1,2,3-triazole ring has been increasingly reported over the last years. The feasible synthesis through copper (I) catalyzed azide-alkyne cycloaddition (CuAAC) has allowed the accomplishment of several hybrids. Since 2017, almost 700 flavonoid hybrids conjugated with 1,2,3-triazole, including chalcones, flavones, flavanones and flavonols, among others, with antitumor, antimicrobial, antidiabetic, neuroprotective, anti-inflammatory, antioxidant, and antifouling activity have been reported. This review compiles the biological activities recently described for these hybrids, highlighting the mechanism of action and structure-activity relationship (SAR) studies.

Alkyne-Tagged Apigenin, a Chemical Tool to Navigate Potential Targets of Flavonoid Anti-Dengue Leads

A flavonoid is a versatile core structure with various cellular, immunological, and pharmacological effects. Recently, flavones have shown anti-dengue activities by interfering with viral translation and replication. However, the molecular target is still elusive. Here we chemically modified apigenin by adding an alkyne moiety into the B-ring hydroxyl group. The alkyne serves as a chemical tag for the alkyne-azide cycloaddition reaction for subcellular visualization. The compound located at the perinuclear region at 1 and 6 h after infection. Interestingly, the compound signal started shifting to vesicle-like structures at 6 h and accumulated at 24 and 48 h after infection. Moreover, the compound treatment in dengue-infected cells showed that the compound restricted the viral protein inside the vesicles, especially at 48 h. As a result, the dengue envelope proteins spread throughout the cells. The alkyne-tagged apigenin showed a more potent efficacy at the EC₅₀ of 2.36 ± 0.22, and 10.55 ± 3.37 µM, respectively, while the cytotoxicities were similar to the original apigenin at the CC₅₀ of 70.34 ± 11.79, and 82.82 ± 11.68 µM, respectively. Molecular docking confirmed the apigenin binding to the previously reported target, ribosomal protein S9, at two binding sites. The network analysis, homopharma, and molecular docking revealed that the estrogen receptor 1 and viral NS1 were potential targets at the late infection stage. The interactions could attenuate dengue productivity by interfering with viral translation and suppressing the viral proteins from trafficking to the cell surface.

Click Chemistry in Natural Product Modification

Click chemistry is perhaps the most powerful synthetic toolbox that can efficiently access the molecular diversity and unique functions of complex natural products up to now. It enables the ready synthesis of diverse sets of natural product derivatives either for the optimization of their drawbacks or for the construction of natural product-like drug screening libraries. This paper showcases the state-of-the-art development of click chemistry in natural product modification and summarizes the pharmacological activities of the active derivatives as well as the mechanism of action. The aim of this paper is to gain a deep understanding of the fruitful achievements and to provide perspectives, trends, and directions regarding further research in natural product medicinal chemistry.

Chemoenzymatic Stereoselective Synthesis of trans-Flavan-4-ols via Lipase-Catalyzed Kinetic Resolutions

Flavan-4-ols are a subclass of flavonoids that are present in complex molecules with application in the industrial sector as pigments, antioxidants, or antimitotics, among many others. The most traditional way to achieve their synthesis is from naturally abundant flavanones, asymmetric transfer hydrogenation reactions or bioreduction being well known strategies, while their preparation from racemic flavan-4-ols has been less explored. In this article, we have focused on the synthesis of a series of trans-flavan-4-ols bearing different substitution patterns in the aromatic ring to explore later the potential of lipases as biocatalysts for stereoselective acylation reactions. Therefore, a series of flavanones have been chemically prepared, starting from the corresponding benzaldehydes by aldol condensation with 2′-hydroxyacetophenone in a strongly basic medium, and later transformed into the corresponding racemic trans-flavan-4-ols following a carbonyl reduction, Mitsunobu reaction, and ester deprotection sequence. A screening of lipases and optimization of the reaction conditions for the stereoselective acylation of racemic 2-phenylchroman-4-ol were performed before expanding the best reaction conditions to the kinetic resolution of other 2-arylchroman-4-ols. Interestingly, the combination of AK lipase from Pseudomonas fluorescens as enzyme and vinyl acetate as both acyl donor and solvent allowed the performance of highly asymmetric transformations (E > 200, 50–99% eeS and >99% eeP) under mild reaction conditions (30 °C and 250 rpm).

Structure Revision of Four Classes of Prenylated Aromatic Natural Products Based on a Rule for Diagnostic 13C NMR Chemical Shifts

Errors in elucidating the structures of four natural classes of prenylated aromatic compounds with 2,3-epoxy, 2,3-dihydroxy, and cyclization with an ortho-phenolic hydroxyl to give a pyran or furan ring moiety are frequent and inevitable. Based on rigorous literature research and a series of chemical transformation experiments, a rule for the rapid determination of these four classes of prenylated derivates based on ¹³C NMR data was formulated, and 57 corrections featuring these fragments were accordingly reported.

1,2,3-Triazole-Containing Compounds as Anti-Lung Cancer Agents: Current Developments, Mechanisms of Action, and Structure-Activity Relationship

Lung cancer is the most common malignancy and leads to around one-quarter of all cancer deaths. Great advances have been achieved in the treatment of lung cancer with novel anticancer agents and improved technology. However, morbidity and mortality rates remain extremely high, calling for an urgent need to develop novel anti-lung cancer agents. 1,2,3-Triazole could be readily interact with diverse enzymes and receptors in organisms through weak interaction. 1,2,3-Triazole can not only be acted as a linker to tether different pharmacophores but also serve as a pharmacophore. This review aims to summarize the recent advances in 1,2,3-triazole-containing compounds with anti-lung cancer potential, and their structure-activity relationship (SAR) together with mechanisms of action is also discussed to pave the way for the further rational development of novel anti-lung cancer candidates.

Bavachinin Induces G2/M Cell Cycle Arrest and Apoptosis via the ATM/ATR Signaling Pathway in Human Small Cell Lung Cancer and Shows an Antitumor Effect in the Xenograft Model

Lung cancer is grouped into small cell lung cancer (SCLC) and non-SCLC (NSCLC). SCLC exhibits a poor prognosis, and the current anticancer treatment remains unsatisfactory. Bavachinin, present in the seed of Psoralea corylifolia, shows anti-inflammatory effects, immune modulation, and anticancer potency. This study aims to investigate the antitumor effect of bavachinin on SCLC and its underlying mechanism. The SCLC cell line H1688 was treated with different concentrations of bavachinin and showed decreased viability with arrested G2/M and sub-G1 phase cell accumulation at a concentration as low as 25 μM. Expression levels of caspase-3, -8, and -9, as well as Fas, FasL, and Bax, increased with the concentration of bavachinin. The accumulated sub-G1 cells and annexin V confirmed increasing apoptotic cancer cells after treatment. The accumulated G2/M phase cells with increasing levels of phosphorylated CDC25C, CDC2, ATM/ATR, and CHK2/CHK1 confirmed the arrested cell cycle caused by bavachinin via a dose-dependent manner. This phenomenon can be reversed by an ATM/ATR inhibitor, caffeine. Following the administration of bavachinin to xenograft mice with SCLC, the tumor burden decreased without impairing hematologic or hepatorenal functions. Bavachinin induces SCLC apoptosis via intrinsic and extrinsic pathways and causes cancer cell cycle arrest via the ATM/ATR signaling pathway.

Synthesis and Antitumor Activity of 1-Substituted 1,2,3-Triazole-Mollugin Derivatives

A new series of mollugin-1,2,3-triazole derivatives were synthesized using a copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition reaction of corresponding O-propargylated mollugin with aryl azides. All the compounds were evaluated for their cytotoxicity on five human cancer cell lines (HL-60, A549, SMMC-7721, SW480, and MCF-7) using MTS assays. Among the synthesized series, most of them showed cytotoxicity and most of all, compounds 14 and 17 exhibited significant cytotoxicity of all five cancer cell lines.

Discovery of a Secalonic Acid Derivative from Aspergillus aculeatus, an Endophyte of Rosa damascena Mill., Triggers Apoptosis in MDA-MB-231 Triple Negative Breast Cancer Cells

A new secalonic acid derivative, F-7 (1), was isolated from the endophytic Aspergillus aculeatus MBT 102, associated with Rosa damascena. The planar structure of 1 was established on the basis of 1D and 2D NMR and ESI-TOF-MS spectra. The relative configuration of 1 was determined applying a combined quantum mechanical/NMR approach and, afterward, the comparison of calculated and experimental electronic circular dichroism spectra determined the assignment of its absolute configuration. The compound possesses strong cytotoxic activity against triple negative breast cancer (TNBC) cells. It was found to induce apoptosis, as evidenced by scanning electron microscopy and phase contrast microscopy. Furthermore, flow cytometry analyses demonstrated that 1 induced mitochondrial damage and reactive oxygen species mediated apoptosis, arresting the G1 phase of the cells in a dose-dependent manner. Also, the compound causes significant microtubule disruption in TNBC cells. Subsequently, 1 restricted the cell migration leading to the concomitant increase in expression of cleaved caspase and PARP.

Targeting hypoxia-inducible factor-1, for cancer treatment: Recent advances in developing small-molecule inhibitors from natural compounds

Rapid progress in molecular cancer biology coupled with the discovery of novel oncology drugs has opened new horizons for cancer target discovery. As one of the crucial signaling pathways related to tumorigenesis, hypoxia-inducible factor-1 (HIF-1) coordinates the activity of many transcription factors and their downstream molecules that impact tumor growth and metastasis. Accumulating evidence suggests that the transcriptional responses to acute hypoxia are mainly attributable to HIF-1α. Moreover, the overexpression of HIF-1α in several solid cancers has been found to be strongly associated with poor prognosis. Thus, pharmacological targeting of the HIF-1 signaling pathways has been considered as a new strategy for cancer therapy in the recent years. Although over the past decade, tremendous efforts have been made in preclinical studies to develop new HIF-1 inhibitors from natural products (reservoirs of novel therapeutic agents), to date, these efforts have not been successfully translated into clinically available treatments. In this review, we provide new insights into the bio-pharmacological considerations for selecting natural compounds as potential HIF-1 inhibitors to accelerate anti-cancer drug development. In addition, we highlighted the importance of assessing the dependency of cancer on HIF1A to shortlist cancer types as suitable disease models. This may subsequently lead to new paradigms for discovering more HIF-1 inhibitors derived from natural products and facilitate the development of potent therapeutic agents targeting specific cancer types.

Potential metabolism determinants and drug-drug interactions of a natural flavanone bavachinin

Bavachinin, a natural bioactive flavanone, is reported to have many pharmacological proprieties, especially anti-osteoporosis activity. Here we aim to determine the roles of cytochrome P450s (CYP), UDP-glucuronosyltransferases (UGT), and efflux transporters in metabolism and drug–drug interactions (DDI) of bavachinin. Phase I metabolism and glucuronidation were performed by human liver microsomes (HLM) and human intestine microsomes (HIM). Reaction phenotyping was used to identify the main CYPs and UGTs. Gene silencing methods were employed to investigate the roles of breast cancer resistance protein (BCRP) and multidrug resistance-associated proteins (MRPs) in HeLa1A1 cells. Inhibition mechanisms towards CYPs and UGTs were explored through kinetic modeling. Three phase I metabolites (M1–M3) and one glucuronide (G1) were detected after incubation of bavachinin with HLM and HIM. The intrinsic clearance (CL_int) values of M1 and G1 by HLM were 89.4 and 270.2 μL min⁻¹ mg⁻¹, respectively, while those of M3 and G1 by HIM were 25.8 and 247.1 μL min⁻¹ mg⁻¹, respectively. CYP1A1, 1A2, 1B1, 2C8, 2C19, and UGT1A1, 1A8 participated more in bavachinin metabolism. The metabolism showed marked species difference. BCRP and MRP4 were identified as the main contributors. Bavachinin displayed potent inhibitory effects against several CYP and UGT isozymes (K_i = 0.28–2.53 μM). Bavachinin was subjected to undergo metabolism and disposition by CYPs, UGTs, BCRP, MRP4, and was also a potent non-selective inhibitor against several CYPs and UGTs.

Metabolism, efflux transport and drug–drug interactions of bavachinin.

Enhancing the Therapeutic Efficacy of Daunorubicin and Mitoxantrone with Bavachinin, Candidone, and Tephrosin

The capability of flavonoids in sensitizing cancer cells was demonstrated in numerous works to chemotherapy and converse multidrug resistance by modulating efflux pumps and apoptosis mechanisms. Three flavonoids, namely, bavachinin, tephrosin, and candidone, have been recently introduced to cancer treatment research presenting various activities, such as antibacterial, immunomodulatory, cell death, and anticancer. Less information exists regarding the therapeutic significance of these flavonoids in cancer treatment, especially in overcoming multidrug resistance (MDR). Here, we tempted to investigate the potency of these agents in reversing MDR by analyzing their effects as chemosensitizers on cell cytotoxicity, P-gp and ABCG2 protein expression levels, and their function on two multidrug-resistant cell lines, P-gp-overexpressing human gastric adenocarcinoma cell line (EPG85.257RDB) and ABCG2-overexpressing human epithelial breast cancer cell line (MCF7/MX). The inhibitory concentration of 10% (IC₁₀) of bavachinin, tephrosin, and candidone in EPG85.257RDB cells was 1588.7 ± 202.2, 264.8 ± 86.15, and 1338.6 ± 114.11 nM, respectively. Moreover, these values in MCF7/MX cell were 2406.4 ± 257.63, 38.8 ± 4.28, and 27.9 ± 5.59 nM, respectively. Expression levels of ABCG2 and P-gp were not significantly downregulated by these flavonoids. Maximum levels of daunorubicin and mitoxantrone accumulations and minimum rates of drug efflux in both cell lines were detected 48 hrs posttreatment with tephrosin and bavachinin, respectively. Chemosensitization to mitoxantrone and daunorubicin treatments was, respectively, achieved in MCF7/MX and EPG85.257RDB cells in response to IC₁₀ of bavachinin and tephrosin, independently. These effects did not follow time-dependent manner, and each flavonoid had its cell-dependent patterns. Overall, bavachinin, tephrosin, and candidone showed potency to sensitize MDR cells to daunorubicin and mitoxantrone and could be considered as attractive MDR modulators for cancer treatment. However, their action was time and cell specific.

1,2,3-Triazole-containing hybrids as potential anticancer agents: Current developments, action mechanisms and structure-activity relationships

Anticancer agents are critical for the cancer treatment, but side effects and the drug resistance associated with the currently used anticancer agents create an urgent need to explore novel drugs with low side effects and high efficacy. 1,2,3-Triazole is privileged building block in the discovery of new anticancer agents, and some of its derivatives have already been applied in clinics or under clinical trials for fighting against cancers. Hybrid molecules occupy an important position in cancer control, and hybridization of 1,2,3-triazole framework with other anticancer pharmacophores may provide valuable therapeutic intervention for the treatment of cancer, especially drug-resistant cancer. This review emphasizes the recent advances in 1,2,3-triazole-containing hybrids with anticancer potential, covering articles published between 2015 and 2019, and the structure-activity relationships, together with mechanisms of action are also discussed.

Study on the 2-Phenylchroman-4-One Derivatives and their anti-MERS-CoV Activities

Study on the 2-phenylchroman-4-one derivatives and their anti-MERS-CoVactivities.

1,2,3-Triazole-containing hybrids as leads in medicinal chemistry: A recent overview

The 1,2,3-triazole ring is a major pharmacophore system among nitrogen-containing heterocycles. These five-membered heterocyclic motifs with three nitrogen heteroatoms can be prepared easily using 'click' chemistry with copper- or ruthenium-catalysed azide-alkyne cycloaddition reactions. Recently, the 'linker' property of 1,2,3-triazoles was demonstrated, and a novel class of 1,2,3-triazole-containing hybrids and conjugates was synthesised and evaluated as lead compounds for diverse biological targets. These lead compounds have been demonstrated as anticancer, antimicrobial, anti-tubercular, antiviral, antidiabetic, antimalarial, anti-leishmanial, and neuroprotective agents. The present review summarises advances in lead compounds of 1,2,3-triazole-containing hybrids, conjugates, and their related heterocycles in medicinal chemistry published in 2018. This review will be useful to scientists in research fields of organic synthesis, medicinal chemistry, phytochemistry, and pharmacology.

Synthesis, characterization and antimicrobial evaluation of ferrocene–oxime ether benzyl 1H-1,2,3-triazole hybrids

A series of ferrocene–oxime ether benzyl 1H-1,2,3 triazole hybrids has been synthesized by employing Cu(i) catalyzed azide–alkyne [3+2] cycloaddition reaction and their antibacterial and antifungal activities are reported.