Design, synthesis and in vitro anticancer activity of novel quinoline and oxadiazole derivatives of ursolic acid

Synthesis, anticancer activity and molecular docking of new quinolines, quinazolines and 1,2,4-triazoles with pyrido[2,3-d] pyrimidines

Recently, heterocyclic compounds such as pyrido [2,3-d] pyrimidinones, 1,2,4-triazolopyrimidines, pyrimidoquinazolines, and quinoline derivatives have gained attention from researchers due to their pharmacological and biological activities. To synthesize new compounds, quinoline-2-thioxopyrido [2,3-d] pyrimidinone (1) and methylthioquinoline-pyrido [2,3-d] pyrimidinones (2) were used as starting materials. The new compounds synthesized were quinoline-pyrido [2,3-d] (DeGoey et al., 2013; Gouda et al., 2020; Dangolani et al., 2018) [1, 2,4]triazolopyrimidinones (5a-d), 2-methylsulfonyl-quinoline-pyrido [2,3-d]pyrimidinone (6), pyrido [2,3-d]pyrimidine derivatives, pyridopyrimido (Gouda et al., 2020; DeGoey et al., 2013) 2,12,1-b] quinazoline (9), pyrido [(Khajouei et al., 2021; Gouda et al., 2020) 3,23,2-e]bis (1,2,4-triazole)pyrimidine (12a,b) and pyridopyrimido-diquinazoline-dione (16) derivatives. These compounds were synthesized with high efficiency, producing yields ranging from 69% to 90%, under moderate conditions, through treating (2) or (10) with various reagents such as anthranilic acid, phosphorus oxychloride, hydrazine hydrate, formic acid, glacial acetic acid, arylamine (aniline, 4-chloroaniline, or 4-methoxyaniline), and sec-amine (piperazine or morpholine). The new structures of the synthesized compounds were verified using various spectroscopic procedures, such as IR, NMR, and mass spectra. Molecular docking studies were carried out to investigate and discuss how the prepared compounds bind to amino acids such as Estrogen Receptor alpha, EGFR, and NADPH oxidase protein. Also, the synthesized products were tested for their anticancer and antioxidant activities against the (MCF-7) breast carcinoma cell line and human normal Retina pigmented epithelium cells (RPE-1). The study on the structure-activity relationship (SAR) established a correlation between the chemical structure of the newly synthesized compounds and their anticancer activity. The findings suggest that compounds 5a-d, 9,12a-b, and 16 exhibited promising anticancer activity and antioxidant effects as measured by DPPH inhibition.

Synthesis of Some New 1,3,4-Oxadiazole Derivatives and Evaluation of Their Anticancer Activity

In this work, some new 2-[(5-((2-acetamidophenoxy)methyl)-1,3,4-oxadiazol-2-yl)thio]acetamide derivatives (4a-4l) were synthesized and studied for their anticancer activity. Twelve new compounds were tested on the A549 human lung cancer cell line, C6 rat glioma cell line, and L929 murine fibroblast cell line. Compounds 4f, 4i, 4k, and 4l (IC50: 1.59-7.48 μM), and especially 4h (IC50: <0.14 μM), exhibited excellent cytotoxic profile on A549 with selectivity. Compounds 4g and 4h showed remarkable antiproliferative activity on the C6 cell line with IC50 values of 8.16 and 13.04 μM, respectively. The compounds with the lowest IC50 value on the A549 cell line (4f, 4h, 4i, 4k, and 4l) were further studied to determine the mechanism of action. These compounds were found to induce apoptosis with a higher ratio (16.10-21.54%) than that of the standard drug cisplatin (10.07%). Compound 4f displayed mitochondrial membrane depolarization and caspase-3 activation at most, whereas compounds 4h (89.66%) and 4i (78.78%) had outstanding retention rates in the G0/G1phase of the cell cycle (cisplatin 74.75%). Compounds 4f, 4g, 4h, and 4l exhibited matrix metalloproteinase-9 (MMP-9) inhibition higher than 75% at 100 μg/mL; even IC50 values were found to be 1.65 and 2.55 μM for 4h and 4l. In addition, in silico physicochemical properties of the compounds and molecular docking interaction of compound 4h on the MMP-9 enzyme were evaluated; the desired and expected results were obtained.

Application of Quinoline Ring in Structural Modification of Natural Products

Natural compounds are rich in pharmacological properties that are a hot topic in pharmaceutical research. The quinoline ring plays important roles in many biological processes in heterocycles. Many pharmacological compounds, including saquinavir and chloroquine, have been marketed as quinoline molecules with good anti-viral and anti-parasitic properties. Therefore, in this review, we summarize the medicinal chemistry of quinoline-modified natural product quinoline derivatives that were developed by several research teams in the past 10 years and find that these compounds have inhibitory effects on bacteria, viruses, parasites, inflammation, cancer, Alzheimer's disease, and others.

Synthesis, Biological Activity, ADME and Molecular Docking Studies of Novel Ursolic Acid Derivatives as Potent Anticancer Agents

A series of new ursolic acid (UA) derivatives substituted with various amino acids (AAs) or dipeptides (DP) at the C-3 position of the steroid skeleton was designed and synthesized. The compounds were obtained by the esterification of UA with the corresponding AAs. The cytotoxic activity of the synthesized conjugates was determined using the hormone-dependent breast cancer cell line MCF-7 and the triple-negative breast cancer cell line MDA. Three derivatives (l-seryloxy-, l-prolyloxy- and l-alanyl-l-isoleucyloxy-) showed micromolar IC₅₀ values and reduced the concentrations of matrix metalloproteinases 2 and 9. Further studies revealed that for two compounds (l-seryloxy- and l-alanyl-l-isoleucyloxy-), a possible mechanism of their antiproliferative action is the activation of caspase-7 and the proapoptotic Bax protein in the apoptotic pathway. The third compound (l-prolyloxy- derivative) showed a different mechanism of action as it induced autophagy as measured by an increase in the concentrations of three autophagy markers: LC3A, LC3B, and beclin-1. This derivative also showed statistically significant inhibition of the proinflammatory cytokines TNF-α and IL-6. Finally, for all synthesized compounds, we computationally predicted their ADME properties as well as performed molecular docking to the estrogen receptor to assess their potential for further development as anticancer agents.

Ursolic Acid Analogs as Potential Therapeutics for Cancer

Ursolic acid (UA) is a pentacyclic triterpene isolated from a large variety of vegetables, fruits and many traditional medicinal plants. It is a structural isomer of Oleanolic Acid. The medicinal application of UA has been explored extensively over the last two decades. The diverse pharmacological properties of UA include anti-inflammatory, antimicrobial, antiviral, antioxidant, anti-proliferative, etc. Especially, UA holds a promising position, potentially, as a cancer preventive and therapeutic agent due to its relatively non-toxic properties against normal cells but its antioxidant and antiproliferative activities against cancer cells. Cell culture studies have shown interference of UA with multiple pharmacological and molecular targets that play a critical role in many cells signaling pathways. Although UA is considered a privileged natural product, its clinical applications are limited due to its low absorption through the gastro-intestinal track and rapid elimination. The low bioavailability of UA limits its use as a therapeutic drug. To overcome these drawbacks and utilize the importance of the scaffold, many researchers have been engaged in designing and developing synthetic analogs of UA via structural modifications. This present review summarizes the synthetic UA analogs and their cytotoxic antiproliferative properties reported in the last two decades.

Friedlӓnder's synthesis of quinolines as a pivotal step in the development of bioactive heterocyclic derivatives in the current era of medicinal chemistry

In the current scenario of medicinal chemistry, quinoline plays a pivotal role in the design of new heterocyclic compounds with several pharmacological properties, so the search for new synthetic methodologies and their application in drug discovery has been widely studied. So far, many procedures have been performed for the preparation of quinoline scaffolds, among which Friedländer quinoline synthesis plays an important role in obtaining these heterocycles. The Friedländer reaction involves condensation between 2-aminobenzaldehydes and keto-compounds. The quinoline nucleus, once obtained through the Friedländer synthesis, has been extensively modified so that these derivatives can exhibit a large number of biological activities such as anticancer, antimalarial, antimicrobial, antifungal, antituberculosis, and antileishmanial properties. In this work, the focus is on the applicability of the Friedländer reaction in the synthesis of various types of bioactive heterocyclic quinoline compounds, which to date has not been reported in the context of medicinal chemistry. The main part of this review selectively focuses on research from 2010 to date and will present highlights of the Friedländer quinoline synthesis procedures and findings to address biological and pharmacological activities.

Recent advances of heterocycle based anticancer hybrids

Cancer is one of the major causes of death across the world. Cancer is a broad word that encompasses a wide range of illnesses that can affect any part of the body. Cancer research has increased understanding of molecular biology and cellular biology, resulting in new cancer therapies. Despite of adverse effects, surgery, radiation, and anticancer medicines are the modern cancer treatments. Keeping in mind the excellent anticancer activity exhibited by various heterocyclics, various medicines with heterocyclic moiety have been developed to identify particular target regions. The chapter aims to discuss new discoveries in the field of anticancer pharmaceuticals comprising the thiazole, pyrazole, oxazole, and triazole rings over the last five years. The proposed anticancer drugs have a lot of future significance due to their high potency.

Synthesis of α,β-unsaturated benzotriazolyl-1,3,4-oxadiazole derivatives: anticancer activity, cytotoxicity, and cell imaging

A series of ten α,β-unsaturated benzotriazolyl-1,3,4-oxadiazole derivatives was synthesized and all compounds were evaluated in vitro against three breast cancer cell lines (MCF-7, MDA-MB-231 and 4T1) at different concentrations (0.1, 0.5, 1, 2, 3, 4 and 5 mg/mL). The results showed that compounds 6a, 6c, 6d, 6f, 6g, and 6i displayed acceptable anticancer activity, where compound 6f was the most active on the three cell lines (IC50 = 0.80, 0.07, and 0.30 mg/mL, respectively). Regarding the cytotoxicity assay, the compounds exhibited modest toxicity on murine splenocytes and peripheral human blood cells at the highest concentration tested (5 mg/mL). Compound 6f was further evaluated at different concentrations showing moderate cytotoxicity at the 5 mg/mL concentration and negligible cytotoxicity at the minimum concentration evaluated (0.05 mg/mL). Finally, the compounds 6a, 6c, 6d, 6f, 6g, 6i, and 6j were evaluated as fluorescence markers due to their ability to be internalized into MCF-7 cells.

Nanoformulations of Ursolic Acid: A Modern Natural Anticancer Molecule

Background: Ursolic acid (UA) is a natural pentacyclic triterpene derived from fruit, herb, and other plants. UA can act on molecular targets of various signaling pathways, inhibit the growth of cancer cells, promote cycle stagnation, and induce apoptosis, thereby exerting anticancer activity. However, its poor water-solubility, low intestinal mucosal absorption, and low bioavailability restrict its clinical application. In order to overcome these deficiencies, nanotechnology, has been applied to the pharmacological study of UA.

Objective: In this review, we focused on the absorption, distribution, and elimination pharmacokinetics of UA in vivo, as well as on the research progress in various UA nanoformulations, in the hope of providing reference information for the research on the anticancer activity of UA.

Methods: Relevant research articles on Pubmed and Web of Science in recent years were searched selectively by using the keywords and subheadings, and were summarized systematically.

Key finding: The improvement of the antitumor ability of the UA nanoformulations is mainly due to the improvement of the bioavailability and the enhancement of the targeting ability of the UA molecules. UA nanoformulations can even be combined with computational imaging technology for monitoring or diagnosis.

Conclusion: Currently, a variety of UA nanoformulations, such as micelles, liposomes, and nanoparticles, which can increase the solubility and bioactivity of UA, while promoting the accumulation of UA in tumor tissues, have been prepared. Although the research of UA in the nanofield has made great progress, there is still a long way to go before the clinical application of UA nanoformulations.

Synthesis and anti-proliferation activity of mogrol derivatives bearing quinoline and triazole moieties

A series of novel derivatives based on mogrol were designed and synthesized in attempt to improve anti-lung cancer activity. The cytotoxicity against human lung cancer cells including A549 and NCI-H460 were performed by Cell Counting Kit-8 (CCK8) assay in vitro. The screening result showed that compound 8f exhibited the strongest activity with an IC₅₀ value of 4.47 μM against A549 cell, and could induce the cell apoptosis in a dose-dependent manner and arrest cell cycle at G0/G1 phase. Besides, compound 8f displayed anti-proliferation effect on A549 cell through inhibiting phosphorylation of signal transducer and activator of transcription 3 (STAT3). Furthermore, compared with morgol, compound 10a significantly improved the cytotoxicity against NCI-H460 with the IC₅₀ value of 17.13 μM. The research stimulated the development of potential therapeutic agent for lung cancer from the natural mogrol.

Synthesis, anticancer evaluation and mechanism studies of novel indolequinone derivatives of ursolic acid

A series of novel indolequinone derivatives of ursolic acid bearing ester, hydrazide, or amide moieties were designed, synthesized, and screened for their in vitro antiproliferative activities against three cancer cell lines (MCF-7, HeLa, and HepG2) and a normal gastric mucosal cell line (Ges-1). A number of compounds showed significant activity against tested cancer cell lines. Among them, compound 6t exhibited the most potent activity against three cancer cell lines with IC50 values of 1.66 ± 0.21, 3.16 ± 0.24, and 10.35 ± 1.63 µM, respectively, and considerably lower cytotoxicity to Ges-1 cells. Especially, compound 6t could arrest cell cycle at S phase, suppress the migration of MCF-7 cells, elevate intracellular reactive oxygen species (ROS) level, and decrease mitochondrial membrane potential. Western blot analysis showed that compound 6t upregulated Bax, cleaved caspase-3/9, cleaved PARP levels and downregulated Bcl-2 level of MCF-7 cells. All these results indicated that compound 6t could significantly induce the apoptosis of MCF-7 cells. Meanwhile, compound 6t markedly decreased p-AKT and p-mTOR expression, which revealed that compound 6t probably exerted its cytotoxicity through targeting PI3K/AKT/mTOR signaling pathway. Therefore, compound 6t could be a promising lead for the discovery of novel anticancer agents.

1,3,4-Oxadiazole Containing Compounds As Therapeutic Targets For Cancer Therapy

BACKGROUND

Cancer is the first or second leading cause of premature death in 134 of 183 countries in the world. 1,3,4-Oxadiazoles are five memebered heterocyclic rings containing two nitrogen (two atoms) and oxygen (one atom). They show better thermal stability, metabolic stability, aqueous solubility and lower lipophilicity than the other isomeric oxadiazoles. They are important class of heterocycles present in many drug structures like Raltegravir, Furamizole Tidazosin, Nesapidil, Setileuton (MK-0633) and Zibotentan. Presence of this nucleus in the therapeutics has made them an indispensable anchor for drug design and development. Several 1,3,4-oxadiazoles are prepared and reported as anticancer agents by numerous scientists worldwide.

OBJECTIVES

The present review discusses the anticancer potentials together with the molecular targets of 1,3,4-oxadiazoles reported since 2010. The structure activity relationship (SAR) and molecular docking simulation on different targets have also been discussed herein. Some of the important cancer targets have also been explored.

METHODS

The most potent 1,3,4-oxadiazoles reported in literature was highlighted in the manuscript. The anticancer activity was reported in terms of growth percent (GP), percent growth inhibition (%GI), GI50, IC50, and LC50 and TGI.

RESULTS

1,3,4-Oxadiazoles are an important heterocyclic scaffolds with broad spectrum biological activities. They may be either mono substituted or disubstituted and act as an indispensable anchor for drug design and discovery due to their thermal stability together with low lipophilicity. They exhibited anticancer potentials and showed the inhibitions of various cancer targets.

CONCLUSION

The discussion outlined herein will proved to be a helpful and vital tool for medicinal chemists investigating and working with 1,3,4-oxadiazoles and anticancer research programs.

Reactive Oxygen Species-Mediated Autophagy by Ursolic Acid Inhibits Growth and Metastasis of Esophageal Cancer Cells

Ursolic acid (UA) possesses various pharmacological activities, such as antitumorigenic and anti-inflammatory effects. In the present study, we investigated the mechanisms underlying the effects of UA against esophageal squamous cell carcinoma (ESCC) (TE-8 cells and TE-12 cells). The cell viability assay showed that UA decreased the viability of ESCC in a dose-dependent manner. In the soft agar colony formation assay, the colony numbers and size were reduced in a dose-dependent manner after UA treatment. UA caused the accumulation of vacuoles and LC3 puncta, a marker of autophagosome, in a dose-dependent manner. Autophagy induction was confirmed by measuring the expression levels of LC3 and p62 protein in ESCC cells. UA increased LC3-II protein levels and decreased p62 levels in ESCC cells. When autophagy was hampered using 3-methyladenine (3-MA), the effect of UA on cell viability was reversed. UA also significantly inhibited protein kinase B (Akt) activation and increased p-Akt expression in a dose-dependent manner in ESCC cells. Accumulated LC3 puncta by UA was reversed after wortmannin treatment. LC3-II protein levels were also decreased after treatment with Akt inhibitor and wortmannin. Moreover, UA treatment increased cellular reactive oxygen species (ROS) levels in ESCC in a time- and dose-dependent manner. Diphenyleneiodonium (an ROS production inhibitor) blocked the ROS and UA induced accumulation of LC3-II levels in ESCC cells, suggesting that UA-induced cell death and autophagy are mediated by ROS. Therefore, our data indicate that UA inhibits the growth of ESCC cells by inducing ROS-dependent autophagy.

Evaluation of ursolic acid derivatives with potential anti-Toxoplasma gondii activity

Toxoplasma gondii is an important pathogen that causes serious public health problems. Currently, therapeutic drugs for toxoplasmosis cause serious side effects, and more effective and novel substances with relatively low toxicity are urgently needed. Ursolic acid (UA) has many properties that can be beneficial to healthcare. In this study, we synthesized eight series of UA derivatives bearing a tetrazole moiety and evaluated their anti-T. gondii activity in vitro using spiramycin as a positive control. Most of the synthesized derivatives exhibited better anti-T. gondii activity in vitro than UA, among which compound 12a exhibited the most potent anti-T. gondii activity. Furthermore, the results of biochemical parameter determination indicated that 12a effectively restored the normal body weight of mice infected with T. gondii, reduced hepatotoxicity, and exerted significant anti-oxidative effects compared with the findings for spiramycin. Additionally, our molecular docking study indicated that the synthesized compounds could act as potential inhibitors of T. gondii calcium-dependent protein kinase 1 (TgCDPK1), with 12a possessing strong affinity for TgCDPK1 via binding to the key amino acids GLU129 and TYR131.

Ursolic Acid-Based Derivatives as Potential Anti-Cancer Agents: An Update

Ursolic acid is a pharmacologically active pentacyclic triterpenoid derived from medicinal plants, fruit, and vegetables. The pharmacological activities of ursolic acid have been extensively studied over the past few years and various reports have revealed that ursolic acid has multiple biological activities, which include anti-inflammatory, antioxidant, anti-cancer, etc. In terms of cancer treatment, ursolic acid interacts with a number of molecular targets that play an essential role in many cell signaling pathways. It suppresses transformation, inhibits proliferation, and induces apoptosis of tumor cells. Although ursolic acid has many benefits, its therapeutic applications in clinical medicine are limited by its poor bioavailability and absorption. To overcome such disadvantages, researchers around the globe have designed and developed synthetic ursolic acid derivatives with enhanced therapeutic effects by structurally modifying the parent skeleton of ursolic acid. These structurally modified compounds display enhanced therapeutic effects when compared to ursolic acid. This present review summarizes various synthesized derivatives of ursolic acid with anti-cancer activity which were reported from 2015 to date.

Novel 3'-Substituted-1',2',4'-Oxadiazole Derivatives of 18βH-Glycyrrhetinic Acid and Their O-Acylated Amidoximes: Synthesis and Evaluation of Antitumor and Anti-Inflammatory Potential In Vitro and In Vivo

A series of novel 18βH-glycyrrhetinic acid (GA) derivatives containing 3'-(alkyl/phenyl/pyridin(-2″, -3″, and -4″)-yl)-1',2',4'-oxadiazole moieties at the C-30 position were synthesized by condensation of triterpenoid's carboxyl group with corresponding amidoximes and further cyclization. Screening of the cytotoxicity of novel GA derivatives on a panel of tumor cell lines showed that the 3-acetoxy triterpenoid intermediates-O-acylated amidoxime 3a-h-display better solubility under bioassay conditions and more pronounced cytotoxicity compared to their 1',2',4'-oxadiazole analogs 4f-h (median IC50 = 7.0 and 49.7 µM, respectively). Subsequent replacement of the 3-acetoxy group by the hydroxyl group of pyridin(-2″, 3″, and -4″)-yl-1',2',4'-oxadiazole-bearing GA derivatives produced compounds 5f-h, showing the most pronounced selective toxicity toward tumor cells (median selectivity index (SI) > 12.1). Further detailed analysis of the antitumor activity of hit derivative 5f revealed its marked proapoptotic activity and inhibitory effects on clonogenicity and motility of HeLa cervical carcinoma cells in vitro, and the metastatic growth of B16 melanoma in vivo. Additionally, the comprehensive in silico study revealed intermediate 3d, bearing the tert-butyl moiety in O-acylated amidoxime, as a potent anti-inflammatory candidate, which was able to effectively inhibit inflammatory response induced by IFNγ in macrophages in vitro and carrageenan in murine models in vivo, probably by primary interactions with active sites of MMP9, neutrophil elastase, and thrombin. Taken together, our findings provide a basis for a better understanding of the structure-activity relationship of 1',2',4'-oxadiazole-containing triterpenoids and reveal two hit molecules with pronounced antitumor (5f) and anti-inflammatory (3d) activities.

Design, synthesis, and anticancer evaluation of novel quinoline derivatives of ursolic acid with hydrazide, oxadiazole, and thiadiazole moieties as potent MEK inhibitors

In this article, a series of novel quinoline derivatives of ursolic acid (UA) bearing hydrazide, oxadiazole, or thiadiazole moieties were designed, synthesised, and screened for their in vitro antiproliferative activities against three cancer cell lines (MDA-MB-231, HeLa, and SMMC-7721). A number of compounds showed significant activity against at least one cell line. Among them, compound 4d exhibited the most potent activity against three cancer cell lines with IC50 values of 0.12 ± 0.01, 0.08 ± 0.01, and 0.34 ± 0.03 μM, respectively. In particular, compound 4d could induce the apoptosis of HeLa cells, arrest cell cycle at the G0/G1 phase, elevate intracellular reactive oxygen species level, and decrease mitochondrial membrane potential. In addition, compound 4d could significantly inhibit MEK1 kinase activity and impede Ras/Raf/MEK/ERK transduction pathway. Therefore, compound 4d may be a potential anticancer agent and a promising lead worthy of further investigation.

Ursolic Acid and Its Derivatives as Bioactive Agents

Non-communicable diseases (NCDs) such as cancer, diabetes, and chronic respiratory and cardiovascular diseases continue to be threatening and deadly to human kind. Resistance to and side effects of known drugs for treatment further increase the threat, while at the same time leaving scientists to search for alternative sources from nature, especially from plants. Pentacyclic triterpenoids (PT) from medicinal plants have been identified as one class of secondary metabolites that could play a critical role in the treatment and management of several NCDs. One of such PT is ursolic acid (UA, 3 β-hydroxy-urs-12-en-28-oic acid), which possesses important biological effects, including anti-inflammatory, anticancer, antidiabetic, antioxidant and antibacterial effects, but its bioavailability and solubility limits its clinical application. Mimusops caffra, Ilex paraguarieni, and Glechoma hederacea, have been reported as major sources of UA. The chemistry of UA has been studied extensively based on the literature, with modifications mostly having been made at positions C-3 (hydroxyl), C12-C13 (double bonds) and C-28 (carboxylic acid), leading to several UA derivatives (esters, amides, oxadiazole quinolone, etc.) with enhanced potency, bioavailability and water solubility. This article comprehensively reviews the information that has become available over the last decade with respect to the sources, chemistry, biological potency and clinical trials of UA and its derivatives as potential therapeutic agents, with a focus on addressing NCDs.

Hybridized Quinoline Derivatives as Anticancer Agents: Design, Synthesis, Biological Evaluation and Molecular Docking

Objective:

Conjugating quinolones with different bioactive pharmacophores to obtain potent anticancer active agents.

Methods:

Fused pyrazolopyrimidoquinolines 3a-d, Schiff bases 5, 6a-e, two hybridized systems: pyrazolochromenquinoline 7 and pyrazolothiazolidinquinoline 8, different substituted thiazoloquinolines 13-15 and thiazolo[3,2-a]pyridine derivatives 16a-c were synthesized. Their chemical structures were characterized through spectral and elemental analysis, cytotoxic activity on five cancer cell lines, caspase-3 activation, tubulin polymerization inhibition and cell cycle analysis were evaluated.

Results:

Four compounds 3b, 3d, 8 and 13 showed potent activity than doxorubicin on HCT116 and three compounds 3b, 3d and 8 on HEPG2. These promising derivatives showed increase in the level of caspase-3. The trifloromethylphenyl derivatives of pyrazolopyrimidoquinolines 3b and 3d showed considerable tubulin polymerization inhibitory activity. Both compounds arrested cell cycle at G2/M phase and induced apoptosis.

Conclusion:

Compounds 3b and 3d can be considered as promising anticancer active agents with 70% of colchicine activity on tubulin polymerization inhibition and represent hopeful leads that deserve further investigation and optimization.

Synthesis and evaluation of the HIF-1α inhibitory activities of novel ursolic acid tetrazole derivatives

The hypoxia-inducible factor-1α (HIF-1α) pathway has been implicated in tumor angiogenesis, growth, and metastasis. Therefore, the inhibition of this pathway is an important therapeutic target for the treatment of various types of cancers. Here, we designed and synthesized 31 ursolic acid (UA) derivatives containing a tetrazole moiety and evaluated them for their potential anti-tumor activities as HIF-1α transcriptional inhibitors. Of these, compound 14d (IC50 0.8 ± 0.2 µM) displayed the most potent activity and compounds 14a (IC50 4.7 ± 0.2 µM) exhibited the most promising biological profile. Analysis of the structure-activity relationships of these compounds with HIF-1α suggested that the presence of a tetrazole group located at C-28 of the UA derivatives was critical for their inhibitory activities.

Design, Synthesis, and Biological Evaluation of Novel Nitrogen Heterocycle-Containing Ursolic Acid Analogs as Antitumor Agents

Nineteen ursolic acid analogues were designed, synthesized, and evaluated for their antiproliferative activity against the Hela and MKN45 cell lines. Some compounds containing a piperazine moiety displayed moderate to high levels of antitumor activities against the tested cancer cell lines. The most potent compound shares the IC50 value of 2.1 µM and 2.6 µM for the Hela and MKN45 cell lines, respectively. Further mechanism studies and in vivo antitumor studies have shown that it decreased the apoptosis regulator (BCL2/BAX) ratio, disrupted mitochondrial potential and induced apoptosis, and suppressed the growth of Hela xenografts in nude mice.

Novel hybrids of benzothiazole-1,3,4-oxadiazole-4-thiazolidinone: Synthesis, in silico ADME study, molecular docking and in vivo anti-diabetic assessment

A series of new benzothiazole-1,3,4-oxadiazole-4-thiazolidinone hybrid analogs (Tz1-Tz28) were synthesized in search of potential anti-diabetic agents. Molecular docking study was conducted with binding pocket of peroxisome proliferator activated receptor-gamma to elucidate the binding interactions of newly synthesized targets. Seven selected compounds with best docking scores were further screened for in vivo anti-hyperglycemic efficacy by oral glucose tolerance test in non-diabetic rats and on streptozotocin induced diabetic rat models. All the tested compounds demonstrated excellent to moderate reduction in blood glucose levels. Three of the compounds (Tz21, Tz7 and Tz10) showed excellent anti-diabetic effect by reducing concentration of glucose to 157.15 ± 1.79 mg/dL, 154.39 ± 1.71 mg/dL, 167.36 ± 2.45 mg/dL, respectively better than the standard drug, pioglitazone, 178.32 ± 1.88 mg/dL. Moreover, three derivatives Tz21, Tz4 and Tz24 with IC50 values of 0.21 ± 0.01 µM, 9.03 ± 0.12 µM and 11.96 ± 0.40 µM respectively also showed better inhibitory activities on alpha-glucosidase even more than the standard acarbose (IC50 = 18.5 ± 0.20 µM), indicating Tz21 has the highest inhibitory effect among the seven tested derivatives. Prediction of Drug like properties using molinspiration online software suggests that all the synthesized compounds have potential of becoming the orally active molecules. Thus, these novel hybrids could serve as potential candidates to become leads for the development of new drugs eliciting anti-hyperglycemic effect orally.

Redox-responsive chemosensitive polyspermine delivers ursolic acid targeting to human breast tumor cells: The depletion of intracellular GSH contents arouses chemosensitizing effects

Antitumor efficacy of ursolic acid (UA) is seriously limited due to its low hydrophilicity and needy bioavailability. To overcome these obstacles, chemosensitive polyspermine (CPSP) conjugated with UA and folic acid (FA) as a novel targeted prodrug was designed and successfully synthesized in this investigation. This prodrug not only showed high aqueous solubility, GSH-triggered degradation and good biocompatibility, but also exhibited better inhibition effect on the tumor cells proliferation in comparison with free UA. FA-CPSP-UA could down-regulate the generation of GSH and manifest excellent ability in enhancing antitumor efficacy. In addition, FA-CPSP-UA could inhibit the expression of MMP-9, which led to restricting MCF-7 cells migration. Taken together, the results indicated that FA-CPSP-UA, as a carrier, can efficiently deliver UA to folate receptor positive cancer cells and improve tumor therapy of UA by Chemosensitive effect.

Discovery of antitumor ursolic acid long-chain diamine derivatives as potent inhibitors of NF-κB

A series of inhibitors of NF-κB based on ursolic acid (UA) derivatives containing long-chain diamine moieties were designed and synthesized as well as evaluated the antitumor effects. These compounds exhibited significant inhibitory activity to the NF-κB with IC50 values at micromolar concentrations in A549 lung cancer cell line. Among them, compound 8c exerted potent activity against the test tumor cell lines including multidrug resistant human cancer lines, with the IC50 values ranged from 5.22 to 8.95 μM. Moreover, compound 8c successfully suppressed the migration of A549 cells. Related mechanism study indicated compound 8c caused cell cycle arrest at G1 phase and triggered apoptosis in A549 cells through blockage of NF-κB signalling pathway. Molecular docking study revealed that key interactions between 8c and the active site of NF-κB in which the bulky and strongly electrophilic group of long-chain diamine moieties were important for improving activity.

A novel synthetic ursolic acid derivative inhibits growth and induces apoptosis in breast cancer cell lines

The present study investigated the anticancer functions of ursolic acid (UA) and its novel derivatives, with a nitrogen-containing heterocyclic scaffold and the privileged fragment at the C-28 position on apoptosis induction, cell proliferation and cell cycle in human BC lines. UA was chemically modified in the present study to increase its antitumor activity and bioavailability. A novel UA derivative, FZU3010, was synthesized using a nitrogen-containing heterocyclic scaffold and a privileged fragment at the C-28 position. Sulforhodimine B assays were used to measure the effect of UA and different concentrations of FZU3010 on the viability of breast cancer (BC) SUM149PT and HCC1937 cells. FZU3010 significantly repressed the proliferation of the two cancer cell lines in a dose-dependent manner, with a half-maximal inhibitory concentration of 4-6 µM, and exhibited decreased cytotoxicity compared with vehicle-treated cell lines. The effect of FZU3010 on cell cycle distribution and cellular apoptosis was also investigated. The results of this investigation indicated that FZU3010 significantly increased the number of SUM149PT and breast cancer HCC1937 cells in the G₀/G₁ phase in a dose-dependent manner. Additionally, at a concentration of 5 µM, the capability of FZU3010 to induce BC apoptosis was significantly higher than the capability of UA. Thus, the results of the current study indicated that FZU3010 induced apoptosis in BC cells, together with induction of cell cycle arrest at the S and G₀/G₁ phase. FZU3010 may therefore be considered as a potential therapeutic agent for the treatment of BC.